June 2017

Birding Farnham-Connolly Memorial Park, Canton

Thu, 01 Jun 2017 00:00:00 GMT

The park has few trails, but all of them provide access to a variety of natural communities including alluvial red maple swamp, mixed oak forest, shallow emergent marsh, and shrub swamp. White pine, quaking aspen, and gray birch are commonly encountered on the trails in the upland portions of the park; red maple, silky dogwood, highbush blueberry, and speckled alder are found in the wetland areas.

In late summer and early fall, some of the trails contain ragweed, smartweed, and foxtail grasses. The weedy conditions attract migrant sparrows and other species that prefer seeds as a food source during migration.

Historically, Least Bitterns were found nesting in the Neponset River Reservation. Although the last breeding record is from 1990, this species could still be present—but as yet undetected—in the cattail marshes found within the park.

While the park can produce interesting bird sightings in all seasons, the focus of this article is the spring and fall migration periods. Because the park is bordered to the west, north, and east by developed sections of the towns of Norwood and Canton, the area has the concentrating effect of a migrant trap. Furthermore, the nearby Neponset River, with its conspicuous north and south orientation, may be a guiding topographical feature utilized by spring and fall migrants.

Fig. 1. Great Lawn. Photograph by Marsha Salett

Please note that the Norwood Airport has air traffic that passes directly over the park. It is best to bird the park before 10:00 am when fewer planes are flying overhead and likely to interfere with the detection of chip notes and other avian vocalizations. Traffic from Interstate 95 (I–95) can also be a source of noise pollution, so an early morning visit is strongly recommended. Be prepared to spend two to three hours at the park during the spring and fall migrations. Most of the trails can be covered thoroughly in just a few hours. Farnham-Connolly Memorial Park is located close to I–95 and is convenient to access for anyone with a desire for pre-work birding or a respite from commuter traffic.

How to Get to Farnham-Connolly Memorial Park

Take I–95 south from the junction of Interstates 95 and 93 for about three miles to Exit 11A-Neponset Street toward Canton. If you are coming from southeastern Massachusetts or Rhode Island on I–95 north, you will also take Exit 11A, but be aware that there is no Exit 10 driving northbound. Travel east on Neponset Street for 0.2 miles and then take a left into the parking area. The traffic on Neponset Street can be challenging during the morning commute, so please exercise caution when entering or exiting the park.

The Great Lawn and Constructed Wetlands Area

The best place to start birding the park is the trail that borders the area that the park signage denotes as the “great lawn,” situated directly north of the parking lot (Figure 1). To access the trail, walk to the northwest corner of the parking lot and take a right. The trail parallels the northern border of the parking lot and leads to several observation platforms overlooking the constructed marshes.

Fig. 2. Constructed wetland attracts Tree and Barn swallows. Photograph by Marsha Salett.

During the fall migration, check the weeds and shrubs growing at the edge of the trail for Eastern Phoebes, Eastern Bluebirds, Palm and Nashville warblers, and Song and Chipping sparrows. Listen for Swamp Sparrows chipping from the cattails nearby and Common Ravens uttering their guttural croaks in the distance. Continue on the trail as it loops around the grassy knoll that affords a decent view of the constructed marsh below (Figure 2). This area has been a productive spot for watching migrating raptors such as Cooper’s and Sharp-shinned hawks. In late September and early October, the manicured areas may host good numbers of Savannah Sparrows. Be sure to listen for Bobolinks flying over this area during the morning flight. Follow the paved path as it loops back toward the parking area and connects with the unpaved main trail.

Directly across the trail is an area bordered by a stone wall and identified on park signage as the “ceremonial lawn.” It is worth exploring this area in the fall since there are usually foxtail grasses and other weeds growing around the perimeter of the walls. Check for sparrows in the weeds, but be sure to take a look at the deciduous trees growing just to the west of this location since the crowns are illuminated shortly after sunrise. These trees are a good place to look for Northern Flickers, Blue-gray Gnatcatchers, and Blue-headed and Warbling vireos after the passage of a cold front. Being at this spot at first light may provide the opportunity to witness American Robins exiting a roost site somewhere in the southwest corner of the park.

Gray Catbird. Photograph by Evan Lipton.

After birding the ceremonial lawn area, return to the main trail and continue north and beyond the great lawn area on the right. In the fall, Chipping and Song sparrows are typically encountered in this area; a Dickcissel made an appearance here in 2015. In addition, the weedy edges on the north side of the great lawn can be a good place to look for migrant sparrows. Vesper Sparrows are possible in spring and fall and the species has been observed at the park as recently as 2016. Continue north on the main trail and look for Tree Swallow nest boxes on either side of the path. Several pairs of Tree Swallows nest here and can be observed investigating the nest boxes in early April. The cattail marsh and wet areas in the vicinity are a good place to look for Spotted and Solitary sandpipers in early May. It is likely that at least one pair of Spotted Sandpipers breeds in this area, so a careful scan of the open areas between the trail and the marsh is definitely warranted. Other noteworthy species that may be observed here in spring include Barn Swallows, Blue-winged Warblers, Field Sparrows, and Purple Finches.

Neponset River Trails

About twenty yards north of the great lawn area, look for a trail on the left just before a stand of quaking aspen trees. Follow this trail west from the main park trail toward the Neponset River. The trail is not long and ends at the river, but a stroll along this route during the spring migration may yield sightings of Ruby-crowned Kinglets, Warbling Vireos, Rose-breasted Grosbeaks, and a variety of warblers. Rusty Blackbirds may be observed in this location from late March through early April. After reaching the end of the trail at the banks of the Neponset River, retrace your steps until you reach a fork in the trail. Taking either trail at the fork will lead back to the main trail and may produce sightings of Carolina and House wrens, Hairy Woodpeckers, Blue-gray Gnatcatchers, Gray Catbirds, Cedar Waxwings, Black-and-white and Yellow-rumped warblers, and American Goldfinches in the spring and fall seasons.

The Marsh Trail

Returning to the main trail, walk north and look for the large circular cement structure on the left. Directly ahead is the marsh trail, approximately one mile long, on what appears to be a former railroad bed. The trail is straight and, in several places, has breaks in the trees that afford great views of the large cattail marsh to the east. Continue north on this trail and look for Dark-eyed Juncos and White-throated Sparrows in the fall. Connecticut Warblers were observed along the first half-mile of the trail in September 2016. The rank weeds growing below the red maples and speckled alders lining the trail are perfect for this elusive species and certainly warrant a close look in mid to late September. Listening for the distinctive dry chimp call is usually key for detecting the presence of this large, but secretive, warbler.

While walking north on the trail, look for the openings in the vegetation for views of the marsh. The habitat here looks good for a variety of marsh birds, so be sure to spend some time scanning the wetlands whenever there is an unobstructed view. The sparsely vegetated areas along the trail can also be good for migrants like House Wrens, Eastern Phoebes, Yellow-rumped Warblers, Northern Waterthrushes, and Savannah Sparrows during the spring and fall migrations. Swamp Sparrows abound in the marsh in these seasons, but are more frequently heard than seen.

House Wren. Photograph by Evan Lipton.

The Red Maple Swamp Trail

The main trail ends at Interstate 95, but there is an approximately quarter-mile trail to the right that traverses red maple swamp habitat. The trail ends at a fence with a warning about the presence of commuter rail tracks just beyond it. Red-bellied Woodpeckers, Blue-gray Gnatcatchers, Northern Waterthrushes, and Black-and-white Warblers may be present along this trail and at the entrance to the swamp. This area is not as productive in the fall, but Carolina Wrens and migrating White-throated Sparrows may be found in the dense understory.

Birding the Park in Other Seasons

Farnham-Connolly Memorial Park has a variety of species that are likely breeders and can be found in the summer months. Green Herons, Willow Flycatchers, Eastern Kingbirds, Black-billed Cuckoos, and Indigo Buntings all have been observed in the months of June and July. In late summer, presumed family groups of Song Sparrows congregate in the weedy areas surrounding the great lawn area. This area may also produce postbreeding dispersed species that have not been observed elsewhere in the park as migrants or breeders, so anyone with a penchant for patch birding may add a few new species to the growing tally.

Because the park has only been open to the public since 2014, there is ample room for ornithological exploration and discovery at a site that is less than a 45-minute drive (on a good day) from the metro Boston area. As mentioned earlier, the park is a great place to go birding if one has limited time or needs a break from the hectic pace of Interstate 95.

To learn more about the park, please visit the following site, which served as a primary source for this article: http://www.mass.gov/eea/docs/dcr/stewardship/rmp/bh/section-5-neponset-river-reservation.pdf

Jim Sweeney has been birding since 1980. He is the compiler for the Taunton/Middleboro CBC, a past vice president of the South Shore Bird Club, a member of Bird Observer’s Board of Directors, and a trip leader for various conservation organizations in Massachusetts. In addition to birding, he has a passion for dragonflies and damselflies, collecting rare natural history books, and exploring the natural history of local patches.

Dorothy R. Arvidson: 1920-2017

Thu, 01 Jun 2017 00:00:00 GMT

Dorothy maintained a high standard of editing and quality. One of her classic contributions to Bird Observer was her article “On Records of Birds,” published in Volume 12, Number 1 in February 1984. Although digital photography now makes documentation of bird identification easier, this article is still a standard for reviewing the aspects of writing a rare bird report. The article details the history of record keeping of birds in Massachusetts, the certain minimal data required of a report, and a list of difficult species that can be confusing.

Dorothy loved to travel, was a friend to many, and was an enthusiastic field companion. She will be missed.

The Complex Relationship Between Birds and Gypsy Moths

Thu, 01 Jun 2017 00:00:00 GMT

Gypsy Moths: The Problem

Most Massachusetts residents are aware of the impact that gypsy moth caterpillars have had in our state over the past few years. If people were not familiar with the name gypsy moth, they surely knew those “big black caterpillars.” In 2015 and 2016, a large part of the state was subject to defoliation by this pest, including portions of Barnstable, Plymouth, and Bristol Counties, the eastern parts of Hampden and Hampshire Counties, southern Middlesex and Worcester Counties, and the northernmost part of Essex County (Figure 1). The gypsy moth is not new to our state—it was first introduced to North America in Somerville, Massachusetts, more than 120 years ago. However, for a couple of decades until the recent outbreak, we had been in a sort of uneasy détente with the pest. This period of calm was made possible by the flourishing of a fungus, Entomophaga maimaiga, starting in 1989 (Hajek 1996). E. maimaiga, known as an “entomopathogenic” fungus because it causes disease in insects, was one of many biological controls released in an effort to combat gypsy moth. It infects gypsy moths at the caterpillar stage, killing the caterpillars late in their life cycle. While this fungus won’t ever be able to eradicate gypsy moths, until recently it kept most infestations in check.

That all changed in early spring of 2015, when parts of the state began to experience drought conditions. By June 2015, the entire state was at a level of Abnormally Dry (D0) or higher according to the U.S. Drought Monitor’s Drought Intensity Scale, with more than half the state at a Moderately Dry level (D1), including Barnstable County and many of the adjacent towns and cities in Bristol and Plymouth County. Like many fungi, E. maimaiga needs moisture and humidity for its spores to germinate. Dry conditions meant the fungus couldn’t thrive, which was a boon for gypsy moth populations. Thousands upon thousands of caterpillars ate their way through the summer, pupated, and by July 2015 had emerged in large numbers as adult moths. These moths went on to produce huge numbers of egg masses that overwintered into 2016.

While there was some drought relief in the winter and spring of 2016, drought conditions returned later that spring throughout much of the state. By July and August 2016, several counties were experiencing Severe Drought (D2) or even Extreme Drought (D3) levels (National Drought Mitigation Center, 2016). The high number of egg masses combined with drought conditions that prevented the fungus from proliferating meant that an even bigger gypsy moth year was on deck. Indeed, aerial surveys by the Massachusetts Department of Conservation and Recreation (DCR) indicated that more than 350,000 acres in the state were defoliated by gypsy moth caterpillars in the summer of 2016 (Massachusetts DCR 2016), a 300,000-acre increase over 2015 and the biggest defoliation in decades (Figure 1).

The 2016 gypsy moth outbreak garnered a lot of attention. When the caterpillars reach their final instars, their large size and black, spiky appearance makes them quite noticeable. At outbreak levels, the caterpillars can frequently be seen migrating to nearby food sources by the hundreds. Defoliations are usually hyper-localized; even in heavily infested areas, one homeowner might see all of his broadleaf trees stripped of foliage, while the yard across the street has minimal tree damage. When the caterpillars pupated and adult moths emerged in July, the initial daytime flight of the males was so massive that it made the evening news (Hager 2016). These recent repeated defoliations have raised questions about possible impacts on the environment, including bird populations. In this article, we look more closely at the complex relationship between birds and gypsy moths. In particular, we examine how gypsy moths might influence the abundance of Massachusetts birds, what the impact on birds might be after repeated defoliations caused by gypsy moth outbreaks, and what impact birds may have on this introduced forest pest.

Fig. 1. 2016 Aerial Survey showing areas damaged by Gypsy Moths.

Gypsy Moth Outbreaks: Direct Impacts

The most obvious direct impact of a major gypsy moth infestation is the defoliation of trees and shrubs. Before we can delve into the effect defoliation can have on birds, we must first understand what it means for plants. Gypsy moth caterpillars will consume the leaves of more than 500 types of trees, shrubs, and vines, including broadleaf and coniferous species. Their preferred targets are oak, birch, poplar, willow, alder, basswood, and apple. They have also been observed eating maple, sassafras, hornbeam, elm, cherry, hickory, and many other common components of hardwood forests in Massachusetts. Older caterpillars (later instars) have been observed eating coniferous species such as pine, spruce, and hemlock, likely because all of their preferred food sources had already been consumed (McManus et al. 1979). As a result, in outbreak years, there are few woody plants in Massachusetts forests whose leaves won’t become gypsy moth caterpillar food.

A single defoliation, even if complete, is unlikely to kill a large, mature tree or shrub. A broadleaf tree, e.g., an oak or a maple, will typically respond to defoliation by putting out a new set of leaves within a few weeks. However, repeated defoliations over the course of several growing seasons can lead to dead branches and eventually dead trees, particularly when environmental conditions are already stressful, such as during a drought. Full defoliations of seedlings and small saplings can lead to plant death much more quickly.

In the eastern part of the state, gypsy moth damage has been occurring after another introduced species, winter moth (Operophtera brumata), has already caused significant defoliation to broadleaf trees such as maple, oak, and elm (Elkinton and Boettner 2016). Since winter moth caterpillars feed from April to early May, trees and shrubs are often just putting out a new set of leaves when gypsy moth caterpillars begin feeding in May and June. That means that the same plants could end up trying to put out a total of three sets of leaves each season. This kind of resource expenditure jeopardizes future growth and the ability of the tree or shrub to survive. Gypsy moth caterpillars that hatch in a part of the state where winter moth has already defoliated the majority of broadleaf trees will also move on to less preferred host trees, such as pine and spruce. Defoliation of these conifers can have more severe and immediate consequences, since conifers do not put out a new set of leaves each year, and producing new needles is an extremely costly use of the tree’s resources.

Gypsy Moth Defoliation: Impacts on Birds

What impact might the defoliation caused by gypsy moths have on birds? The first most obvious point is that defoliation removes shelter, reducing the number of suitable nesting sites for ground- and tree-nesting birds, including many of our songbirds. Defoliation also potentially reveals nesting sites to predators and may cause nesting birds to abandon their nests. Unfortunately, peak defoliation during a gypsy moth infestation occurs in July, which typically coincides with critical points in the nesting season for local birds (Thurber et al. 1994). Nest exposure when young birds are readying to fledge means they become visible to predators at a time when they are in some respects most vulnerable.

In addition, exposure of the forest floor to sunlight following defoliation of the upper canopy and the shrub layer, typical of a severe gypsy moth outbreak, can lead to indirect impacts on forest fauna. The lack of foliage means less shade, causing the forest floor to experience higher daytime temperatures and a lack of humidity that ground-nesting birds may find inhospitable (Smith and Lautenschlager 1981). The opening up of the shrub layer may also encourage predators to move into the area if they perceive prey is accessible (Smith and Lautenschlager 1981). Birds that forage in the leaves of live trees and shrubs may also encounter a lack of foraging sites and could experience food shortages later in the season because little food is left to support native caterpillars.

Late-instar female gypsy moth caterpillar. Photograph by Jennifer Forman Orth.

All of these factors imply that, in the short term, the forest environment can become inhospitable for breeding birds following a gypsy moth outbreak. Various studies have attempted to measure this impact. Smith and Lautenschlager (1981) noted that in infested areas where refoliation does occur, the birds and mammals will flee but will return to the area within two to three months. In an experiment done with artificial nests (Thurber, McClain, and Whitmore 1994), nest predation was higher in defoliated sites, and predation was also more frequent for ground nests than for nests placed more than one meter off the ground. Gypsy moth infestations are also associated with decreases in bird species associated with closed canopy forests (Gale, DeCecco, McClain, Marshall, and Cooper 2001), which makes sense because defoliation dramatically alters the makeup of the canopy.

Over several years, repeated defoliation of the upper canopy of the forest can lead to tree death. But these dead trees may be beneficial for some bird species. For example, Eastern Towhee is a ground- and shrub-nesting species that forages in the forest understory and thrives in early successional habitat. Bell and Whitmore (1997) found that populations of Eastern Towhee increased following a gypsy moth outbreak, because the defoliation opened up the canopy, and the sunlight exposure led to the creation of a denser shrub layer. Thurber, McClain, and Whitmore (1994) noted that the growth of the shrub understory following defoliation of the upper canopy should bring in additional birds, but that this increase in bird numbers would also attract mammalian predators, suggesting that the net impact on birds might be neutral. These authors also predicted that birds nesting in the mid to upper canopy, such as Scarlet Tanager, Eastern Wood-Pewee, and Wood Thrush, would experience increased predation following defoliation. However, Bell and Whitmore (2000) found that for shrub and sub-canopy nesters, e.g., Indigo Bunting and Wood Thrush, the creation of additional shrub habitat offset any negative impacts due to predation.

Snags—standing deadwood—resulting from tree death can also become nesting locations for some species. Showalter and Whitmore (2002) found that overall abundance of cavity-nesting birds increased for the first five years following a gypsy moth outbreak, though that abundance then decreased over the following six years. In that study, primary cavity nesters such as Red-bellied Woodpecker, Pileated Woodpecker, and Northern Flicker were found to have a positive association with snags, as did secondary cavity nesters such as Black-capped Chickadee, and these species were found to take advantage of new nesting habitat created by snags immediately following an outbreak. However, populations of other primary cavity nesters, including Downy Woodpecker, Hairy Woodpecker, Tufted Titmouse, and White-breasted Nuthatch, did not increase when the number of snags increased, leading the authors to surmise that other factors suppress their populations.

There has also been some discussion if creation of snags following several years of defoliation might negatively impact ground-nesting birds by leading to increased nest predation or parasitization by birds that use the snags as perches to spot prey. However, research has not demonstrated a significant impact, with one study showing no increase in raptor predation or nest parasitization (Bell and Whitmore 1997), and a separate study showing that the creation of larger snags did not lead to an increase in nest parasitization by cowbirds (Bell and Whitmore 2000). In both studies, the authors suggested that the buildup of the shrub canopy following defoliation of the upper canopy limited opportunities for predation and parasitization by concealing any nests that were present.

Gypsy Moths as a Food Source

Gypsy moths start out their lives inside light brown egg masses that are laid by the female moths, mainly on tree trunks and branches but sometimes on outdoor furniture and other structures. The egg masses are a combination of eggs and hairs from the body of the female moth. The caterpillars hatch from the eggs in early to mid-May, and at their earliest life stages—the first few instars—can be found hiding on the undersides of mostly intact leaves. During this time, the hairs covering the caterpillars are smaller and thinner than the robust bristles found on later instars, when the caterpillars are larger and closer to pupation. The caterpillars pupate in late June or early July, forming dark brownish-red pupal cases that can often be found in clusters on tree trunks, fences, or the sides of buildings. The adult moths emerge from the pupal cases after about two weeks. The male moths are grey, and it is these males that you will see in flight during big outbreak years, or attracted to lights at night. The females are white and much larger than males, and though they have wings, they cannot fly. Instead, they usually flutter around the area where they emerged from their pupae, until a male arrives to mate.

Birds have varying interests in gypsy moths as a food source, depending on the bird species in question and the life stage of the insect. Table 1 includes a list of 41 Massachusetts bird species documented as having eaten one or more life stages of the gypsy moth. Only five species have been documented eating egg masses, presumably because the masses are covered with hairs from the body of the female, rendering them distasteful or difficult to eat (Leonard 1981). Nonetheless, Forbush and Fernald (1896) noted that Black-capped Chickadees and House Sparrows eat the eggs, and White-breasted Nuthatches have been observed picking at the egg masses to get at other insects underneath. In contrast, in areas of Europe where gypsy moth is native, several bird species are known to eat the egg masses, as reported by Campbell (1981). As with the egg masses, the pupae are seldom eaten by birds in the eastern United States, though Hairy Woodpeckers, Eastern Wood-Pewees, cuckoos, vireos, and other species have been observed doing so (Smith 1985).

Most observations about the consumption of gypsy moths by birds come from the caterpillar life stage (larvae). The majority of this information comes from gut studies done by Forbush and Fernald (1896). During outbreak years, they found that significant percentages of the gut content of several bird species consisted of gypsy moth caterpillars. However, not many bird species have adapted to eat hairy caterpillars such as those of the gypsy moth. A study done by Whelan, Holmes, and Smith (1989) found that North American bird species generally prefer nonhairy caterpillars, and if offered both gypsy moth caterpillars and a nonhairy species in a feeding experiment, they will preferentially choose the nonhairy species. That study also found that birds were more willing to accept earlier gypsy moth instars, likely because the hairs were less distasteful or obtrusive to the birds. Leonard (1981) also noted that many more bird species will consume early instar gypsy moth larvae. In contrast, Smith and Lautenschlager (1981) investigated the gut contents of 17 different bird species and found that the majority contained mainly late-instar larvae, even though sampling was done in both June and July. It is difficult to know, though, if Smith’s results reflect a preference that birds have for mature gypsy moth caterpillars or a shortage of preferable food.

Black-billed Cuckoos are caterpillar specialists. Photograph ©Shawn P. Carey.

Notable among our woodland birds as predators of gypsy moth caterpillars are the cuckoos. Yellow-billed and Black-billed cuckoos are caterpillar specialists, eating both hairy and spiny caterpillars. They can eat these caterpillars specifically because they have evolved the fascinating ability to regrow their stomach linings. Once the cuckoo’s stomach lining is completely clogged with hairs and spines from the caterpillars it has digested, the bird regurgitates the used stomach lining in a pellet form, removing all the spines and hairs along with it (Forbush 1907, cited in Bent 1940). Both cuckoo species, along with grackles and Red-winged Blackbirds, are attracted to gypsy moth infestations and will enter new territory once the caterpillars reach outbreak levels (Leonard 1981). Once these birds arrive, they consume large numbers of the caterpillars. Other opportunistic species known to be attracted to gypsy moth caterpillar infestations include crows, Chipping Sparrows, starlings, and cowbirds (Smith and Lautenschlager 1981), though Smith (1985) noted that the Chipping Sparrows he captured had no gypsy moth caterpillars in their guts. There is also a second suite of birds that, rather than arriving only when outbreak levels are high, instead eat gypsy moth caterpillars as a regular part of their diet, presumably helping to keep the pests at low levels until an outbreak occurs. This group includes Black-capped Chickadee, Blue Jay, Eastern Towhee, Baltimore Oriole, and Gray Catbird (Smith and Lautenschlager 1981), all of which are relatively common species that forage in a wide variety of habitats and often produce at least two broods per season.

A few bird species have also been documented eating adult gypsy moths. Blue Jays, for example, have been observed vigorously feeding on adult male moths during outbreak years. Specifically, Blue Jays on Cape Cod were seen congregating on tree trunks and lower branches right after sunrise, targeting the resting area of the moths. As the day went on and the moths left the tree trunks to hide in nearby shrub foliage, the Blue Jays were observed foraging in the shrubs, pulling the male moths from the undersides of leaves, even flying repeatedly straight into the shrubs, flapping their wings in order to scare up and dislodge the hiding moths (Odell 1977 cited in Smith and Lautenschlager 1981). Other bird species that feed on adult gypsy moths include Indigo Bunting, Ovenbird, Common Yellowthroat, and Eastern Phoebe. Nonetheless, the adult moths are not known to be a significant part of the diet of any bird species.

Direct Impacts of Gypsy Moth Infestations on Birds

It makes sense that the caterpillar life stage of gypsy moth is the most important to birds, because caterpillars are active when birds are nesting, and fledglings are frequently fed caterpillars for their high protein content (Smith and Lautenschlager 1981). Gale, DeCecco, McClain, Marshall, and Cooper (2001) found that short-term impacts of a gypsy moth caterpillar influx on bird abundance were numerous. For example, Black- and Yellow-billed cuckoos, noted caterpillar specialists, increased in local abundance two years before the gypsy moth hit outbreak levels and then were gone as soon as the outbreak abated. Indigo Buntings had a similar increase right before an outbreak but took about five years to get back down to typical population levels.

Family	Common Name	Scientific Name	Life Stages of Gypsy Moth Consumed
Cuculidae	Yellow-billed Cuckoo	Coccyzus americanus	L, P
	Black-billed Cuckoo	Coccyzus erythropthalmus	L, P

Picidae	Downy Woodpecker	Picoides pubescens	E, L
	Hairy Woodpecker	Picoides villosus	L, P
	Northern Flicker	Colaptes auratus	L

Tyrannidae	Eastern Wood-Pewee	Contopus virens	L, P, A
	Least Flycatcher	Empidonax minimus	L, A
	Eastern Phoebe	Sayornis phoebe	P, A
	Great Crested Flycatcher	Myiarchus crinitus	P, A
	Eastern Kingbird	Tyrannus tyrannus	P, A

Vireonidae	White-eyed Vireo	Vireo griseus	L
	Yellow-throated Vireo	Vireo flavifrons	L, P, A
	Red-eyed Vireo	Vireo olivaceus	L, P, A

Corvidae	Blue Jay	Cyanocitta cristata	E, L, P, A
	American Crow	Corvus brachyrhynchos	L, P, A

Paridae	Black-capped Chickadee	Poecile atricapillus	E, L, P, A

Sittidae	White-breasted Nuthatch	Sitta carolinensis	E

Troglodytidae	House Wren	Troglodytes aedon	L

Turdidae	Eastern Bluebird	Sialia sialis	L, P, A
	Wood Thrush	Hylocichla mustelina	L
	American Robin	Turdus migratorius	L, P, A

Mimidae	Gray Catbird	Dumetella carolinensis	L, P, A
	Brown Thrasher	Toxostoma rufum	L, P, A

Sturnidae	European Starling	Sturnus vulgaris	L

Passeridae	House Sparrow	Passer domesticus	E, L, P, A

Parulidae	Ovenbird	Seiurus aurocapilla	L, A
	Black-and-white Warbler	Mniotilta varia	L, A
	Common Yellowthroat	Geothlypis trichas	L, A
	American Redstart	Setophaga ruticilla	L, A
	Yellow Warbler	Setophaga petechia	L, P, A
	Chestnut-sided Warbler	Setophaga pensylvanica	L, A
	Black-throated Green Warbler	Setophaga virens	L, A

Emberizidae	Eastern Towhee	Pipilo erythrophthalmus	L, P, A
	Chipping Sparrow	Spizella passerina	L, A

Cardinalidae	Scarlet Tanager	Piranga olivacea	L, P, A
	Rose-breasted Grosbeak	Pheucticus ludovicianus	L
	Indigo Bunting	Passerina cyanea	A

Icteridae	Red-winged Blackbird	Agelaius phoeniceus	L
	Common Grackle	Quiscalus quiscula	L
	Brown-headed Cowbird	Molothrus ater	L
	Baltimore Oriole	Icterus galbula	L, P, A
Legend: E = eggs, L = Larvae, P = Pupae, A= Adults

Table 1. Massachusetts bird species that are known to eat gypsy moths. Sources: Forbush and Fernald (1896), McManus et al. (1979), Smith and Lautenschlager (1981).

In contrast to years where gypsy moths are present but not at outbreak levels, or are rising in numbers but in extremely limited geographical areas, years of extensive infestation can result in food pulses being injected into the forest ecosystem. One study looked at the impact of these repeated pulses on bird abundance over three decades in Connecticut, Pennsylvania, and Virginia, and found an overall increase in populations of all woodpecker species over time, suggesting that the woodpeckers have learned to take advantage of outbreak years (Koenig, Walters, and Liebhold 2011). Research has found few other long-term trends, because the impacts of the moths are too variable. Koenig’s study also found that, over shorter time periods, Red-headed Woodpecker and Northern Flicker numbers increased during the breeding season in outbreak years, whereas Downy Woodpecker populations decreased. Though some bird species tie their breeding cycle to times when caterpillars are most abundant (Hinks et al. 2015), we have no evidence that such synchronization occurs specifically with gypsy moth outbreaks, perhaps because these outbreaks generally occur several years apart and last for only one to three years. Taken together, these studies suggest either that short-term trends are not good predictors of long-term bird populations, or that the long-term woodpecker success found by Koenig was related to factors other than gypsy moth outbreaks. Gale DeCecco, McClain, Marshall, and Cooper (2001) concluded that impacts of gypsy moth on birds will always be short-term, provided that there is little tree mortality.

Gypsy Moths, Framingham. Photograph by Jennifer Forman Orth.

Bird Impacts on Gypsy Moths

Much of the older research on birds and gypsy moths has focused on if birds could reduce populations of this pest, thus alleviating an outbreak. Campbell (1977, in Campbell 1981) found that excluding birds and small mammals from experimental plots had a stronger impact on gypsy moth populations than excluding mammals alone. Smith and Lautenschlager (1981) also noted that migrating warblers sometimes pass through forests when gypsy moth caterpillars are young and could make a dent in populations in areas where they stop to rest.

Gypsy moth caterpillars are generalists, feeding on many different plants. The “enemy-free space cascade hypothesis” suggests that, unlike host-specific caterpillars, caterpillars that use many host plants will in turn have a variety of predators feeding on them, and that this predator pressure from birds will create a strong trophic cascade down the food chain that leads to a significant decrease in herbivory (Singer et al. 2014). However, once an outbreak occurs, predation by birds and other predators has been found to be insufficient to affect gypsy moth populations (Smith and Lautenschlager 1981). As much as defoliation impacts the forest in the short term, the cyclical nature of gypsy moth outbreaks, in combination with the fact that gypsy moths are important food sources for only a few predators (Smith 1985), means that the overall effect of birds on gypsy moths is limited.

That conclusion has not, however, kept some from suggesting natural “solutions” involving birds as a way of combating the gypsy moth problem. In Eurasia, nesting boxes are frequently placed in outbreak areas to encourage cavity-nesting birds to settle in the area, with the hope that the birds will consume caterpillars (Leonard 1981, Smith and Lautenschlager 1981). Leonard (1981) also recommends retaining brush in the forest understory as a way to promote populations of ground- and shrub-nesting species. Others have suggested that foresters should plant and encourage tree species that would provide the most habitat and shelter for bird species known to eat gypsy moth (Smith and Lautenschlager 1981). Unfortunately, because current research indicates that birds do not control gypsy moth populations in outbreak years, it is unlikely that such strategies will lead to control of gypsy moth outbreaks. Perhaps that is because there is already enough food available for birds to thrive without consuming gypsy moths, or because so few bird species actually prefer the caterpillars of gypsy moths if other more palatable caterpillars are available.

Gypsy Moth in Massachusetts: What Does the Future Hold?

There are now parts of Cape Cod, Bristol, Plymouth, and Worcester Counties that have experienced at least two consecutive years of high gypsy moth infestations and severe tree defoliation. The volume of egg masses on the trees in outbreak areas indicate that 2016 was once again a very successful reproductive year for gypsy moth. The Massachusetts DCR is currently predicting a third year of significant defoliations in 2017. Even though early spring storms in 2017 have alleviated drought conditions across most of Massachusetts, the two preceding years of dry conditions mean that there will likely not be enough Entomophaga maimaiga spores around this summer to truly knock down gypsy moth caterpillar populations (Massachusetts DCR 2017).

Adult male gypsy moth. Photograph by Jennifer Forman Orth.

What would another year of defoliation mean for the future of forests in Massachusetts? As discussed above, long-term impacts of gypsy moth infestations on forest ecology are typically limited because the outbreaks do not last longer than one to three years, thus restricting the number of tree deaths and allowing bird populations to quickly recover or to decline following any bumps in abundance. But some parts of the state are now heading into what could be their third or even fourth year of high gypsy moth levels. If drought conditions return in the summer of 2017 or in subsequent years, the repeated defoliations and associated tree deaths that occur could lead to this pest setting back the process of succession in some forests (Bell and Whitmore 1997). The drought itself will only compound the problem, because lack of water can hasten death in a tree or shrub already damaged by defoliation or disease. Under such stresses, hardwood forest ecosystems may be altered, as selective pressure will favor species that gypsy moth does not like to eat (Twery 1991). These species would include trees such as ash, butternut, walnut, dogwood, tulip poplar, and catalpa, as well as shrubs such as American holly, mountain laurel, and rhododendron (McManus et al. 1979). Drought-resistant plants may also gain a competitive advantage.

It is difficult to predict how bird populations may be affected in the areas of Massachusetts most impacted by gypsy moth. Will the pine barrens in southeastern Massachusetts be reduced to nothing but low, scrubby shrubs, grasses, and herbs, with the canopy hospitable only to cavity-nesting birds that can take advantage of all the snags? Will the repeated exposure of the floors of oak and hickory forests to sunlight, combined with the death of nearby trees, create opportunities for invasive shrubs and small trees such as buckthorn, burning bush, barberry, and shrub honeysuckle? If so, there might be increased habitat for ground- and shrub-nesting bird species. On the other hand, forests might be unable to regenerate a closed canopy, with the open habitat remaining inhospitable to Scarlet Tanager, Eastern Wood-Pewee, and the warbler species that nest high in trees.

This review has examined the complicated relationship that has developed in Massachusetts among birds, the woodlands they inhabit, and the gypsy moth, an introduced pest that has festered in our state for over a century. Moth outbreaks, especially in the presence of other stresses such as drought, can substantially alter forest structure, and therefore avian habitat, in the shortterm and may also potentially have some impact over longer periods of time. Some bird species will benefit from these alterations, and others will lose out. The fact that these interactions are happening within the context of a changing climate adds further complexity, as does the potential introduction of other forest pests, pathogens, and invasive plants. With a large and skilled birding community and a long history of documented research into the state’s avian populations, Massachusetts is well positioned to support future studies to examine this issue from a wider perspective, with the hope that we can identify issues that put birds at risk and work toward alleviating them.

References

Bell, J.L. and R.C. Whitmore. 1997. Eastern Towhee Numbers Increase Following Defoliation by Gypsy Moths. The Auk. 114 (4): 708-16.
Bell, J.L. and R.C. Whitmore. 2000. Bird Nesting Ecology in a Forest Defoliated by Gypsy Moths. The Wilson Bulletin. 112 (4): 524-31.
Bent, A.C. 1940. Life Histories of North American Cuckoos, Goatsuckers, Hummingbirds and Their Allies: Orders Psittaciformes, Cuculiformes, Trogoniformes, Coraciiformes, Caprimulgiformes and Micropodiiformes. Washington: U.S. Government Printing Office.
Campbell, R.W. 1981. Population Dynamics - Historical Review (Chapter 4). in The Gypsy Moth: Research Toward Integrated Pest Management. Technical Bulletin 1584: pages 65-86. C.C. Doane and M.L. McManus, editors. Washington: U.S. Forest Service, Science and Education Agency, Animal and Plant Health Inspection Service.
Elkinton, J. and J. Boettner. 2016. Gypsy Moth Outbreak of 2016. Massachusetts Wildlife Magazine. #3. Accessed April 14, 2017.
Forbush, E.H. and C.H. Fernald. 1896. The Gypsy Moth. Porthetria dispar (Linn.). Boston: Wright & Potter. Accessed April 14, 2017.
Gale, G.A., J.A. DeCecco, M.R. Marshall, W.R. McClain, and R.J. Cooper. 2001. Effects of Gypsy Moth Defoliation on Forest Birds: An Assessment using Breeding Bird Census Data. Journal of Field Ornithology. 72 (2): 291-304.
Hager, C. Moth Swarm Interferes With Plane At Logan Airport. July 6, 2016. CBS News Boston. Accessed April 3, 2017.
Hajek, A.E. 1996. Entomophaga maimaiga: A Fungal Pathogen of Gypsy Moth in the Limelight. Proceedings of the Cornell Community Conference on Biological Control. 42: 1-2.
Hinks, A.E., E.F. Cole, K.J. Daniels, T.A. Wilkin, S. Nakagawa, and B.C. Sheldon. 2015. Scale-Dependent Phenological Synchrony between Songbirds and Their Caterpillar Food Source. The American Naturalist. 186 (1): 84-97.
Koenig, W.D., E.L. Walters, and A.M. Liebhold. 2011. Effects of Gypsy Moth Outbreaks on North American Woodpeckers. The Condor. 113 (2): 352-61.
Leonard, D.E. 1981. Bioecology of the Gypsy Moth (Chapter 2). In The Gypsy Moth: Research Toward Integrated Pest Management. Issue 1584: pages 9-29. C.C. Doane and M.L. McManus, editors. Washington: U.S. Forest Service, Science and Education Agency, Animal and Plant Health Inspection Service.
Massachusetts Department of Conservation and Recreation. State Environmental Officials Predict Another Year of Defoliation from Gypsy Moth in 2017. January 1, 2017. Massachusetts Department of Conservation and Recreation. Accessed April 3, 2017.
Massachusetts Department of Conservation and Recreation. Forest Health: Massachusetts Forest Pest Aerial Survey Maps. 2015-16. Massachusetts Department of Conservation and Recreation. Accessed April 2, 2017.
McManus, M.L., D.R. Houston, and W.E. Wallner. 1979. Gypsy Moth Handbook: The Homeowner and the Gypsy Moth: Guidelines for Control. Washington: U.S. Department of Agriculture, Combined Forest Pest Research and Development Program, Home and Garden Bulletin.
National Drought Mitigation Center. 2016. United States Drought Monitor - Massachusetts Tabular Data Archive. Accessed April 14, 2017.
Showalter, C.R. and R.C. Whitmore. 2002. The Effect of Gypsy Moth Defoliation on Cavity-Nesting Bird Communities. Forest Science. 48 (2): 273-81.
Singer, M.S., I.H. Lichter-Marck, T.E. Farkas, E. Aaron, K.D. Whitney, and K.A. Mooney. 2014. Herbivore diet breadth mediates the cascading effects of carnivores in food webs. Proceedings of the National Academy of Sciences. 111 (26): 9521-26.
Smith, H.R. 1985. Wildlife and the Gypsy Moth. Wildlife Society Bulletin. 13 (2): 166-74.
Smith, H.R. and R.A. Lautenschlager. 1981. Population Dynamics - Gypsy Moth Predators (Chapter 4). in The Gypsy Moth: Research Toward Integrated Pest Management. Issue 1584: 96-125. C.C. Doane and M.L. McManus, editors. Washington: U.S. Forest Service, Science and Education Agency, Animal and Plant Health Inspection Service.
Thurber, D.K., W.R. McClain, and R.C. Whitmore. 1994. Indirect Effects of Gypsy Moth Defoliation on Nest Predation. The Journal of Wildlife Management. 58 (3): 493-500.
Twery, M.J. 1991. Effects of Defoliation by Gypsy Moth. Proceedings of the U.S. Department of Agriculture Interagency Gypsy Moth Research Review. pages 27-39. Gottschalk, K.W., M.J. Twery and S.I. Smith, editors. Radnor, PA: U.S. Forest Service General Technical Report NE-146.
Whelan, C.J., R.T. Holmes, and H.R. Smith. 1989. Bird Predation on Gypsy Moth (Lepidoptera: Lymantriidae) Larvae: An Aviary Study. Environmental Entomology. 18 (1): 43-5.

Jennifer Forman Orth is an Environmental Biologist at the Massachusetts Department of Agricultural Resources, where she works on insect and plant pest issues. An avid macro photographer, she typically spends the wee hours stalking insects with a camera and flashlight.

Matt Pelikan lives on Martha’s Vineyard and is the conservation measures manager for the Massachusetts chapter of The Nature Conservancy. A former editor of Bird Observer, he is an enthusiastic observer of wildlife of all kinds.

The History, Birds, Research, and Conservation Efforts on Seal Island National Wildlife Refuge

Thu, 01 Jun 2017 00:00:00 GMT

Seal Island’s rocky cliffs and pools attract nesting seabirds and migratory songbirds. All photographs by the author unless otherwise indicated.

As John dodges the lobster buoys that sprinkle the ocean, he points out the birds, geology, cetaceans, and anything related to the local natural history. His passion for the ocean and all its inhabitants brightens up even the roughest crossings of the bay. As you putt closer to SINWR, you start to notice small rafts of alcids on the water and terns hovering over the surface hunting for their next meal. Once the island is in sight, the sheer number of birds becomes obvious. Thousands of terns swirl above the colony on the northwestern point and hundreds of puffins loaf on the rocky boulder berm that surrounds the island. I will never forget the feeling when I first stepped onto SINWR for the first time in 2014. It was breathtaking and it left me speechless. I quickly realized that I would be living in a place still ruled by birds. The five biologists living on the island would be the minority species, a rare phenomenon in today’s world.

The living quarters on SINWR are modest. Each person on the island gets his own tent platform and tarp, which becomes his new home anywhere from two weeks to the entire field season of four months. A small 12-foot by 12-foot cabin is centrally located between the platforms as is a composting outhouse toilet. There is no running water on the island and dishes are washed by hand with rainwater or seawater. Inside the cabin, there is storage for research equipment, a small table for dining, a desk for data entry and management, a marine radio for emergencies and communication between islands, and a small kitchen area with a two-burner propane camp stove. A bath is usually just a swim in the frigid Atlantic but once you get out you can enjoy a seat next to the campfire. Life is simple on the island. It seems like it always has been, and I think this wildness will continue to attract future generations of biologists who learn from the seasoned souls continuing their generous efforts to conserve seabirds and teach others.

A bird blind in the tern colony of Seal Island NWR where puffineers conduct studies on chick diet and read band numbers throughout the nesting season.

The History of SINWR

During the eighteenth and nineteenth centuries, humans exploited seabird colonies along the coast of Maine for the trade of feathers, eggs, and meat. By the early 1800s, the populations of many seabirds, including the Atlantic Puffin, plummeted and puffins occupied only two islands in the Gulf of Maine, nearby Matinicus Rock and Machias Seal Island at the mouth of the Bay of Fundy. Sadly, Matinicus Rock was hit so hard that only a single pair of puffins survived into the twentieth century.

After the extirpation of its diverse seabird colony, SINWR was home to a small fishing camp and today some descendants of its inhabitants still fish the rich waters surrounding the island. However, the island was closed to all activities from the 1940s to 1960s when the U.S. Navy used it as a bombing range. Unfortunately the impacts are still seen on the island and it remains closed to the public due to concerns over unexploded ordinance. Once the bombing ceased, Seal Island’s ownership was transferred to the Department of the Interior but it wasn’t until the U.S. Fish and Wildlife Service and Project Puffin took over management of the island that seabirds began to return.

An Atlantic Puffin returns to its burrow with a bill load of hake. This photo was part of a greater feeding study to track the diet of puffin chicks from season to season.

In an effort to reestablish Atlantic puffin populations, between 1984 and 1989 one thousand 10- to12-day-old puffin chicks were transplanted from Great Island in Newfoundland to artificial sod burrows where they were handfed and raised by biologists living on the island. The hope was that these puffins would return not to their natal colony in Newfoundland, but by becoming familiar with the sights and sounds of their new home on SINWR, would return to breed here instead upon maturation. To encourage the transplanted puffins as well as other roving Gulf of Maine puffins to nest on the shores of the island, Project Puffin’s Dr. Steve Kress used social attraction methods such as decoys and mirrors, which were strategically placed at locations that could be viewed by puffins at sea. This made the island appear like a thriving puffin colony. It wasn’t until 1992—eight years after the first translocations—that puffins first began to breed on SINWR. Similar social attraction techniques also were used to attract Common and Arctic terns, which began to nest on the island in 1989. Since these attraction methods were implemented, the diversity and numbers of nesting seabirds have continued to increase.

Alcids	Black Guillemot	~ 600+
	Atlantic Puffin	~ 510
	Razorbill	~ 35
Terns and Gulls	Common Tern	~ 1200
	Arctic Tern	~ 900
	Herring Gull	~ 400
	Great Black-backed Gull	~ 50
Cormorants	Double-crested Cormorant	~ 25
	Great Cormorant	~ 17
Tubenoses	Leach’s Storm-petrel	~ 700

Table 1. A list of the breeding sea bird species and the estimated number of breeding pairs.

Breeding Birds on Seal Island NWR

During the summer, SINWR hosts a diverse suite of nesting seabirds (Table 1). Although research on the island focuses on three alcids—Atlantic Puffins, Razorbills, and Black Guillemots—in addition to Common and Arctic terns, many other birds also nest on the island. In fact, 17 pairs of Great Cormorants—nearly half of all the known pairs breeding in the United States—nest on SINWR. In 2016, all 42 pairs that were confirmed breeding in the United States nested on four islands in the Penobscot Bay Region. This small population in Maine has rightly earned a threatened status from the state. SINWR’s Great Cormorants consistently have been the most productive colony of Great Cormorants in Maine primarily due to efforts of the resident interns to deter Bald Eagle predation, which has been problematic at other nesting colonies.

A more common species breeding on SINWR is the Leach’s Storm-Petrel whose charming purr calls often lull you to sleep. The last census of Leach’s Storm-Petrel on SINWR was in the 1990s when approximately 700 pairs were estimated to be nesting on the island. Other species such as Double-crested Cormorants, Common Eiders, and Herring and Great Black-backed gulls are monitored through an annual census conducted visually from either land or boat, or by surveying a subset of the island that is easily accessible by foot. Other species that are not intensively monitored but breed on the island include Spotted Sandpipers, Common Yellowthroats, Savannah and Song sparrows, and in some years Yellow Warblers and American Black Duck.

Interns head out to the tern colony to conduct productivity checks. They will band and monitor chicks from hatching until fledging to study annual growth and survival.

A Day in the Life of a Puffineer

Biologists, interns, and volunteers working for Project Puffin are affectionately referred to as puffineers. Being a puffineer is no easy task and often involves countless hours in bird blinds, crawling in and out of rocky burrows, and meticulous data collection. For more than two decades, puffineers have been getting up at 6:00 am to set up spotting scopes and clipboards at the same designated location to count the number of alcids, gulls, cormorants, and eiders that are visible in the water or on land. This is appropriately called the “morning bird count.” After the morning bird count, we record the weather conditions including: sea surface temperature, ambient air temperature, wind speed, visibility, cloud cover, and sea surface conditions, all of which are all recorded three times a day.

After the morning data collection is completed and everyone has had a hearty breakfast, we typically head out to the tern colony for our productivity checks. Since terns first started nesting on SINWR, puffineers have followed a subset of Common and Arctic tern nests to determine their productivity—the number of chicks fledged per nest—and to assess chick growth metrics through banding and measuring. At the beginning of the field season when terns begin to lay eggs, each nest receives a unique identification number and the number of eggs in each nest is recorded daily. Once hatching begins, chicks receive a unique nine-digit band issued by the USGS Bird Banding Laboratory so that they can be identified. Every other day, basic morphometric data, including wing chord and mass, are collected to track growth rates during the nesting season from hatching until fledging. Similar studies also are conducted on Atlantic Puffins, Razorbills, and Black Guillemots. However, checking their nests is much more difficult because they nest among granite boulders that border the edge of the island.

The rocky boulder berms that surround the island are home to nesting Atlantic Puffins, Black Guillemots, and Razorbills. The bird blind is strategically placed to observe alcids nesting behaviors.

After checking the nests and chicks, we often move into bird blinds for the next three hours. During these stints, we conduct a variety of activities. Before many of the chicks hatch, most of our attention is focused on reading the bands of the adult birds through spotting scopes. We use these data to monitor nest site and mate fidelity as well as longevity.

Once the tern and puffin chicks begin to hatch we conduct feeding studies. A subset of nests that are close to bird blinds are monitored from the day the first chick hatches to the day all the chicks have fledged. Using binoculars, we observe each nest for a total of 12 hours per week through multiple three-hour long blind stints. When a feeding is delivered to a chick, the observer records the time, the species of the prey item, the size of the prey item, the individual chick receiving the prey item, and the parent that delivered the prey item. This information is valuable because it allows researchers to follow the diets of seabird species through time and provides valuable information to those managing fish populations.

An Arctic Tern delivers a large sand lance to its young chick.

In addition to productivity checks and blind stints, there are a myriad of other activities that are completed only once a week or during a small window of the season. For example, each year we conduct an annual census of nearly all the breeding species. For some species, such as terns, puffineers carefully walk transects across the nesting colony and count the number of nests and eggs. For other species, we use visual counting methods from land or by boat. Visual observations are particularly useful for species such as puffins that do not nest in the open or for species such as Great Cormorants that nest in an area that is inaccessible without severe disturbance. Other research tasks include keeping a daily bird list, conducting shorebird surveys during migration, and conducting dawn to dusk feeding rate studies on puffins to calculate the average number of feedings a chick gets daily. Needless to say, there is always something to keep a puffineer busy.

Birding on SINWR

Although I have birded in Kenya and Tanzania, the Peruvian Amazon and Andes, Mexico, and across the United States, SINWR is one of the most unusual places I ever have been birding. Because SINWR lies at the outer edge of Penobscot Bay, in spring and fall when migrating birds get blown out to sea with a westerly wind, the first land they come across in their efforts to return to the mainland are the islands smattering the coast of Maine. SINWR is unique in that it lies farther out to sea than other nearby islands and its narrow snakelike shape, which runs essentially south to north for about one mile, is particularly attractive to migrating songbirds.

Spring Migration

Spring migration on SINWR is rewarding. Unlike the mainland, the lack of trees provides migrating songbirds with few places to land comfortably. Instead, they use the steep rocky cliffs, crevices, and brackish pond edges as their hunting grounds to fuel up on insects for the next leg of their migration. The first migrants to arrive on the island during the first week of May are Palm and Yellow-rumped warblers, Chipping, White-throated, and Swamp sparrows, and Hermit Thrushes. In addition, the first week of May is often the only time during the entire field season when lingering wintering species such as Iceland Gull, Harlequin Duck, and Purple Sandpiper can be seen. By the end of the first week of May, the breeding terns begin to arrive. Often during their first week on the island they are heard and seen courting and flying high overhead for about an hour after dawn before departing far beyond the horizon to the east, only to return the following morning.

A Blackburnian Warbler stops on the lichen-covered rocks of Seal Island NWR.

During the second and third weeks of May, a strong push of warblers comes through the island. Blackburnian Warblers are a favorite as their stunning black and orange plumage contrast with the granite rock boulders. In the past two years alone, I have seen 25 species of warbler on Seal Island. I think my favorite part of spring migration is that you get amazingly good views of nearly every bird. Whether they are canopy-dwelling species like the Blackburnian Warbler, a skulky species such as the Mourning Warbler, or a boreal breeding species such as the Cape May, Tennessee or Bay-breasted warbler, all are forced to forage in the open, allowing for ample time to respectfully study and appreciate.

I have noticed that many species of migrants find a way to fill a unique foraging niche on the island. For example, Black-and-White Warblers, Red-breasted Nuthatches, and Downy Woodpeckers use the steep lichen-covered boulder cliffs and the cabin, as a substitute for trees. Flycatchers often find an elevated boulder to sally for insects over grassy fields or gullies. Northern Waterthrushes bob their way along the edges of brackish pools, thrushes use the open muddy flats and rocky caverns, and warblers jump from rock to rock, often leaping and flitting straight up to catch an insect out of the air. And of course, Merlin and Peregrine Falcons are almost always waiting atop the highest perches for a songbird to make the wrong move.

A Blackpoll Warbler perches on a granite boulder. They are one of the most common migrants on Seal Island NWR and one of my favorites.

Another fascinating phenomenon that I have had the fortune to witness is fallout. Large groups of birds will often land on the island around 9:00 or 10:00 am. This fallout is likely due to the effect of birds returning west after being pushed out over the ocean with overnight westerly winds. The most notable fallout was early in May 2016 when more than 200 White-throated Sparrows covered the grassy area surrounding our cabin.

Shorebirds and Fall Migration

Early in July, shorebirds mark the beginning of the fall migration. Ruddy Turnstones and Short-billed Dowitchers pick their way through the rockweed at low tide and roost among the flocks of terns at high tide. Greater and Lesser yellowlegs frequent the many brackish ponds. Whimbrels march through the expansive fields on the southern end of the island. Semipalmated Plovers and Sanderlings feed on the large flat expanses of algae-covered granite exposed at low tide. Least and Semipalmated sandpipers are a common sight through July and August and if you are lucky, a more unusual peep may be among them. On several occasions, I have observed Stilt Sandpipers, some still in breeding plumage, among the flocks of yellowlegs. More than once, I have flushed dowitchers feeding in the muddy trail in route to my tent. During a blind stint one may look out to sea and observe migrating flocks of shorebirds. My most exciting shorebird observation from a bird blind was a small group of Hudsonian Godwits in high breeding plumage flying low over the open ocean in early July 2015. Early migrating species and postbreeding dispersal bring new songbirds to the islands, including Yellow Warblers and Empidonax flycatchers. Intriguingly, the past two seasons I have observed significantly more flycatchers in fall than in spring and the exact opposite phenomenon with warblers, but I don’t know if this is a regular pattern. It is not uncommon to come across western vagrants such as Yellow-headed Blackbird, Lark or Clay-colored sparrows, or even a Dickcissel.

The lone resident Red-billed Tropicbird flies through the tern colony.

By the end of August and into the beginning of September, a surge of young Baird’s Sandpipers comes through. They frequent the rocky flat sections of the island devoid of any vegetation and sprinkled with brackish, algae filled pools. Additionally, raptors start moving south and often stop on SINWR for a quick snack. The most common species are Merlin and Peregrine Falcon, but seeing a Sharp-shinned Hawk is not out of the question. The past two seasons I have also enjoyed a nice push of Northern Gannets that often gracefully glide across the island in the evening likely trying to catch some of the only remaining thermals of the day. Unfortunately, puffineers are usually off the island by the beginning or middle of September. I have no doubt that given the opportunity to remain on the island through the entirety of the fall migration, we could observe even more species.

Rarities

One of the most exciting parts about being a field biologist—and birder—with Project Puffin is that you never know what, when, and if a rare bird will show up on one of the islands. I can’t count the number of times that I was walking to my tent, the outhouse, or a bird blind and came across an unusual bird. All seven of the islands managed by Project Puffin have a long history of rarities including Sooty and Bridled terns, Yellow-nosed Albatross, Curlew Sandpiper, Eurasian Jackdaw, Prothonotary Warbler, Plumbeous Vireo, Black-necked Stilt, and Fork-tailed Flycatcher, just to name few. Since 2005, a Red-billed Tropicbird has spent time on SINWR and Matinicus Rock and has become famous in the birding community. It was first seen on SINWR on July 12, 2005, with an additional sighting the following day on Machias Seal Island at the mouth of the Bay of Fundy. In subsequent years, the bird became quite faithful to Matinicus Rock, but in 2009 it moved back to SINWR where it has since been spending its summers under a large boulder when it isn’t trying to fit in with the unwelcoming Common and Arctic terns.

Although most years are not highlighted by mega-rarities, I have been particularly lucky to observe 189 bird species on SINWR in just the past two seasons. During the summer of 2015, rarities included unusual spring records of Forster’s Tern, American Golden-Plover, and Orange-crowned Warbler, a small group of Bohemian Waxwings, Yellow-headed Blackbird, Lark Sparrow, Clay-colored Sparrows and a young Yellow-crowned Night-heron.

The summer of 2016 was especially fruitful, highlighted by a young King Eider, Hooded Warbler, Olive-sided Flycatcher, Royal Tern, White-winged Dove, high numbers of Cory’s Shearwaters, and the island’s first Upland Sandpiper record. And what a thrill it was to see two new state records for Maine. The first was an Ancient Murrelet that John Drury pointed out to me. What a rush it was to see this Pacific alcid among Razorbills! Just when I thought the summer couldn’t get any better, I found a Great Knot mixed in with some Ruddy Turnstones after a morning thunderstorm blew past the island. This bird represents one of only a handful of records for the lower 48 states and is the first for the Atlantic Coast!

I like to point out to birders that what we often consider to be common species on the mainland can sometimes be big-time rarities for the islands. For example, in the summer of 2016, a Turkey Vulture soaring over the island was a huge surprise and had never been recorded on SINWR. In addition, in 2015 a House Sparrow spent several days around the outhouse, which was one of only a handful of times this species has been recorded on the island. One species that I have dreamed about seeing on the island is a Tufted Titmouse, of all things. It is a common feeder bird for many, but to see one fly over open water is a totally different story. Many raptor species, especially buteos, are incredibly rare on the island, presumably due to the lack of thermals over the cool waters of Penobscot Bay. Perhaps my favorite part of birding on the island is that you gain a true appreciation for all birds both common and rare. Over the course of the summer you might only see one House Wren and maybe only a handful of Dark-eyed Juncos. After not seeing a common species regularly for weeks or months on end, seeing just one individual on the island can bring an excitement and unrealized appreciation for that species.

The Future of Seabirds in the Gulf of Maine

It is no surprise that seabirds in the Gulf of Maine are under significant pressure due to warming sea surface temperatures and rapidly changing environmental conditions caused by climate change and anthropogenic impacts (Mills et al. 2013). Over the past decade, Steve Kress, the director of Project Puffin, has noted significant changes in the diet and condition of Atlantic Puffin chicks. Some prey species such as the Atlantic Herring have declined in the diet while others such as haddock, redfish, and butterfish have increased (Kress et al. 2016). In the summer of 2012, large butterfish were common. Chicks often cannot swallow these fish due to their wide, deep-bodied shape, which left many chicks starving. Fortunately, butterfish are not typically a major prey species in chick diet but, if warming sea surface trends continue, it may facilitate a northward shift of their current southerly distribution (Kress et al. 2016).

Kress (2016) also has noted an annual decrease in the growth rate of puffin chicks at nearby Matinicus Rock. These declines are attributed to the annually increasing trends in sea surface temperatures and declining overall primary productivity in the Gulf of Maine (Kress, 2016). To effectively manage seabird populations in this dynamic world, we must gain a better understanding of how climate change and warming sea surface temperatures are interacting with seabird diet in addition to chick growth and survival at local levels.

Using data collected over the past 25 years by Project Puffin and all its dedicated puffineers, I will be investigating these questions through the completion of my master’s thesis as a fellow with the Northeast Climate Science Center at the University of Massachusetts Amherst. I will focus primarily on the Common, Arctic, and Roseate terns, using this long-term data set to quantify how prey composition has changed in chick diets in relation to observed changes in the environment and how these changes may ultimately impact chick growth and survival. In addition to my own research, there are several other students, biologists, and volunteers throughout New England who are researching the best ways to help these seabird populations thrive for decades to come.

References

Kress S. W., P. Shannon, C. O’Neal. 2016. Recent changes in the diet and survival of Atlantic puffin chicks in the face of climate change and commercial fishing in midcoast Maine, USA, Facets 1: 27-43.
Mills, K. E., A. J. Pershing, C. J. Brown, Y. Chen, F.-S. Chiang, D. S. Holland, S. Lehuta, J. A. Nye, J. C. Sun, A. C. Thomas, and R. A. Wahle. 2013. Fisheries management in a changing climate: Lessons from the 2012 ocean heat wave in the Northwest Atlantic. Oceanography 26:191–195.

Additional Online Links

Keenan’s Photos: https://www.flickr.com/photos/scolopax
Project Puffin: http://projectpuffin.audubon.org
Maine Coastal Island NWR: https://www.fws.gov/refuge/maine_coastal_islands
Northeast Climate Science Center: https://necsc.umass.edu

Keenan Yakola is a fellow with the Northeast Climate Science Center, a master’s candidate in the Department of Environmental Conservation at the University of Massachusetts Amherst, and during the summer months, the Supervisor of Seal Island National Wildlife Refuge with Project Puffin. Keenan is also a native of Cape Cod, Massachusetts; some of his first experiences with birds included working with Mass Audubon’s Wellfleet Bay Wildlife Sanctuary, the Cape Cod National Seashore, and local bird bander Susan Finnegan. He has also spent time working with birds in the Peruvian Amazon and Andes, Kenya and Tanzania, as well as several other locations across the United States.

Musings from the Blind Birder: Lists

Thu, 01 Jun 2017 00:00:00 GMT

Bob and I pay most attention to a number of lists. For Massachusetts, we keep a state list as well as county lists. Each year, we try to see as many birds as possible in Orleans County in Vermont, where our property is, and we attempt to do what we can for the two other counties in the Northeast Kingdom, Essex and Caledonia counties. We also feed off each other’s excitement when a new bird shows up on our Vermont property, such as the Olive-sided Flycatcher that stopped by briefly during one spring migration and announced itself by singing from atop a tree outside our kitchen window. We have so far recorded 112 species on our property. I always look forward to sitting on our Vermont deck in early summer, sipping our morning mugs of coffee, while Bob checks to see if there are any eBird alerts about a species seen in our area that we still need for the year. If there is, our morning’s plans are solidified in that instant.

For those birders who undertake big year efforts, where they try to find as many species as possible in a single year for the region of interest, most would likely say that in the process, their birding skills improved, sometimes greatly. With the intensity and frequency of birding required to amass a notable year list, often with the assistance of expert local guides from whom you can learn, increasing your birding skills can be a by-product of such efforts. I certainly had to marvel at Noah Strycker’s recent achievement of recording over 6,000 species in one year as he traversed the world, writing a blog along the way. Whatever one thinks of such efforts, they do raise awareness about birds and related conservation measures.

In truth, preparing and entering lists takes some discipline and time, and so cannot be dismissed as frivolous scorekeeping. How many times have I sat in the car while Bob meticulously tries to count the hundreds of waterfowl in the water, taking notes on his totals before he forgets them? Or the times that he counts the Snow Buntings that alight on the ground for only seconds before swirling off in a huge flock to the air for yet a few more seconds and then alighting again elsewhere? We might sit there for 10 or 15 minutes trying to come up with the best possible estimate we can, and we take those estimates seriously.

Compiling lists after each foray into the field obviously is a major source of data for researchers monitoring population trends and other aspects of the bird’s ecology. We can take heart not only in having fun but also in knowing that we are, in some small way, contributing to the vast data being collected by amateur birders worldwide.

The life list by geographic region is also a valued part of birding. And why not? Any bird that would be a new addition to your life list is cause for dropping whatever you are doing and going for it. While nonbirders think this is a bit crazy and perhaps overzealous, it is all part of the fun, competition, and goal-oriented nature of birding. Maintaining lists is a purpose in and of itself and a means of recording not only the birds we see but also the experiences surrounding the birds, as well as memories of those we may have seen the birds with. So, when Bob looks at the Red-footed Falcon in his Massachusetts life list, it conjures not just the magnificent bird, but the frenzy of leaving the Museum of Comparative Zoology in Cambridge in midafternoon with Jeremiah Trimble to catch a ferry to Martha’s Vineyard where they met Vern Laux for the mad dash to the airport to spot and confirm the first North American record of this species. For me, my life Boreal Chickadee brings to mind an afternoon with my friend, Jane Connet, high above the tree line in the White Mountains of New Hampshire. Jane and I were sitting on a rock eating lunch when a beautiful Boreal Chickadee landed in a small shrub about a yard away. Even though I had never seen this bird, I knew right away what it was. It sat there for a few seconds, all of us staring at one another before it took off. I am sure that every birder has multiple stories similar to this and that these stories bring smiles and laughter with their recollections.

So, lists are not just records of what we see; they are also reminders of the memories about the people and circumstances surrounding the sightings that we so meticulously record after each day of birding. They give structure to our daily lives and always represent goals which we strive to achieve. The next time you go up to your attic and pull out one of those shoe boxes with hand-written field cards marked with checks next to the birds you saw that day, or browse your old eBird records, think about the memories associated with that card or record. More likely than not, it will bring a broad smile to your face.

Martha Steele, a former editor of Bird Observer, has been progressively losing vision due to retinitis pigmentosa and is legally blind. Thanks to a cochlear implant, she is now learning to identify birds from their songs and calls. Martha lives with her husband, Bob Stymeist, in Arlington. Martha can be reached at marthajs@verizon.net.

Gleanings: Lessons from the Labyrinth

Thu, 01 Jun 2017 00:00:00 GMT

In the avian and mammalian sinuses, respiratory chonchae are complex and convoluted passages that amplify the surface area available for regulation of heat and moisture by countercurrent exchange. During inhalation, the chonchae help to raise the temperature and humidity of incoming air to match internal conditions, and during exhalation, to recapture heat and humidity. Avian chonchae occur in symmetrical pairs, often rostral, middle, and in some species, caudal. Associated with chonchae are rich vascular beds, facilitating thermoregulation throughout the body.

Danner, et al. (2017) set out to test the hypothesis that the internal respiratory chonchae would be more extensive in birds adapted to warmer climates. They studied two subspecies of Song Sparrow (Melospiza melodia) that live in different habitats. Melospiza m. melodia inhabits wide swaths of the eastern United States in relatively moist environments. Melospiza m. atlantica is restricted to dry, sandy, dune areas along the coast between New Jersey and North Carolina. The authors used CT (Computed Tomography) scans of liquid-preserved specimens of the two subspecies to determine the extent and complexity of chonchae. In addition, dried specimens were analyzed by radiography for nasal cavity size—as a proxy for choncha size—and by caliper for bill length, width, and depth. Measurements on these dried specimens confirmed that atlantica has a larger bill with greater surface area than does melodia, suggesting greater heat-radiation capability.

CT scans indicated that Song Sparrows have rostral and middle chonchae and lack caudal structures. The rostral choncha consists of a central plate with side ridges that interdigitate with ridges that arise from the nasal septum and the lateral wall of the nasal cavity. The middle choncha consists of a scroll-shaped structure that is simpler than the rostral choncha. Inspired air travels through the rostral choncha to the middle choncha and then to the pharynx and trachea.

As hypothesized, surface area of chonchae was significantly higher in atlantica than in melodia. Considered separately, rostral and middle chonchae areas were both larger in atlantica. The maximum complexity did not differ between subspecies, though the site maximum complexity was more distal in atlantica. So the anatomic differences between the subspecies in bill size and chonchae development are consistent with climatic selection pressures on chonchae development. It stands to reason that in a drier climate, a larger area for water recovery during exhalation would have a selective advantage due to improved water economy. And it is possible that the more distal maximal complexity in atlantica leads to more efficient water collection, due to lower temperatures in the distal part of the bill. It might seem that more efficient water collection on exhalation would imply more heat retention, which would be less advantageous in the hot dry conditions in the dunes. However, heat recapture seems to be greatest at low ambient temperatures, suggesting that larger chonchae would not be as advantageous in warmer climes.

Bill and chonchae size are closely correlated and probably evolve in tandem. It is likely that the time of maximal temperature stress and selection pressure for the atlantica subspecies is in the hot, dry summer rather than the temperate winter. Hence, large chonchae and bill sizes provide adaptive advantages. In melodia, the cold winters are likely the stressors rather than the hot, humid summers. Therefore smaller bills would favor less heat loss in the winter. Larger chonchae would do the same, but they may be constrained by the need for smaller bill size.

Although this project has elucidated a connection between anatomic features and habitats, with a logical evolutionary basis, it is unclear if these findings are generally applicable to other widespread species of birds, or even to other New World sparrows. Song Sparrows seem to have especially complex chonchae compared to other passerines studied. Additionally, it would be interesting to see if the anatomic differences between the two subspecies demonstrated in this paper are consistent with physiological measurements of expired gases.

Reference

Danner, R.M., E.R. Gulson-Castillo, H.F. James, S.A. Dzielski, D.C. Frank III, E.T. Sibbald, and D.W. Winkler. 2017. Habitat-specific Divergence of Air Conditioning Structures in Bird Bills. The Auk 134 (1): 65-75.

David M. Larson, PhD, is the Science and Education Coordinator at Mass Audubon’s Joppa Flats Education Center in Newburyport, the Director of Mass Audubon’s Birder’s Certificate Program and the Certificate Program in Bird Ecology (a course for naturalist guides in Belize), a domestic and international tour leader, President of the Nuttall Ornithological Club, and a member of the editorial staff of Bird Observer.

Field Notes: Nesting Mourning Doves Tolerate Human Presence

Thu, 01 Jun 2017 00:00:00 GMT

Fig. 3. The young birds are feathering out.

What I found interesting in my neighbor’s nesting pair of Mourning Doves was their tolerance of human disturbance and presence. The homeowners, Robert and Janice Giannetti, frequently spent hours sitting on their porch less than eight feet from the nest and persons walking up to their side door would pass within two feet of the nest. At one point, Janice put her hand within six inches of the sitting adult dove but it did not flush and its only response was to slightly raise some of its back feathers. Once while I was photographing the nest, there were four adult humans present, talking and walking around. This instance of tolerance for human intrusion is not unique. An early study of Mourning Dove nesting found that about one sixth of nesting Mourning Doves stayed on their nests until touched or nearly so before flying (Nice 1923). Clearly, Mourning Doves are genetically driven to remain on the nest while incubating and brooding.

Fig. 4. One fledgling moments after flying from the nest for the first time.

Mourning Doves have a suite of adaptations that promote multiple brooding and saving energy during reproduction. These adaptations include the building of minimal nest structures, reuse of old nests including those of other species, rapid nestling growth, and early fledging (Mirarchi and Baskett 1994). In her study of mourning Doves, Nice (1922) reported that about 15% of Mourning Dove nests were re-used nests of a variety of species including robins, mockingbirds, House Sparrows, Common Grackles, and Mourning Doves.

Fig. 5. Mourning Doves nesting in a dorm room at Wheaton College, Massachusetts. Photograph courtesy of John Kricher.

Mourning Dove nests are so flimsy that you can sometimes see the eggs through the bottom of the nest. Man-made structures are often sturdy and protected, thus supplying structural support and protection for flimsy nests. It seems possible that tolerance for human disturbance contributes to the frequency of use of man-made structures for nesting and may be a prerequisite for doing so. I speculate that if the tolerance of human disturbance when incubating or brooding indeed has a genetic component, then during storms when flimsy nests in trees are at risk, the use of secure man-made structures and its concomitant tolerance of human disturbance may be characteristics selected for. There are many bird species that have adapted to the use of man-made structures for nesting—the Chimney Swift (Chaetura pelagica) is perhaps the most obvious. Perhaps the Mourning Dove is evolving in that direction.

Literature cited

Davis, W. E., Jr. 2014. Mourning Doves Nest on Man-made Structure. Bird Observer 42: 100-101.
Mirarchi, R. E., and T. S. Baskett. 1994. Mourning Dove (Zenaida macroura). In The Birds of North America, No. 117 (A. Poole and F. Gill, Eds.). Philadelphia: The Academy of Natural Sciences; Washington, D.C.: The American Ornithologists’ Union.
Nice, M. M. 1922. A study of the nesting of Mourning Doves, part 1. Auk 39: 457-474.
Nice, M. M. 1923. A study of the nesting of Mourning Doves, part 2. Auk 40: 37-58.
Sayre, M. W., and N. J. Silvy. 1993. Nesting and Production. Pp. 81-104 in T. S. Baskett, M. W. Sayre, R. E. Tomlinson, and R. E. Mirarchi, eds., Ecology and Management of the Mourning Dove. Harrisburg, Pennsylvania: Stackpole Books.

Ted wishes to thank John Kricher for his helpful comments on the manuscript and Janice and Robert Giannetti for bringing attention to this nesting pair of Mourning Doves.

Field Notes: Great Gray Owl

Thu, 01 Jun 2017 00:00:00 GMT

Most of the people watching were in a single group as the owl briefly sat in a white pine about fifty yards away, except for one woman, Marsha Richelli, standing by herself in the middle of the field, watching from afar. The owl took off from its prominent branch to begin its evening hunt and glided down to the center of the field where a lone perch appeared to stand. The last thing anyone could have expected was for the owl to choose to perch on a human being, but to the owl, she looked like a perfect place to sit and hunt from, with access to the field around her. She became the center of attention for a good fifteen seconds as the Great Gray stood on her head and looked around. Amazingly, she stood still and was very calm as the huge owl gently put down. The owl soon realized that its perch was alive and took off to find an inanimate spot to hunt from. As it left the site, I decided I had observed this wonder for long enough and started my journey home. That day, I earned an awesome lifer and created an incredible memory!

Of note: as a boreal species, Great Gray Owls are fairly unaccustomed to humans and have little experience with us. In addition to Great Grays not having a natural fear of us, this bird was also identified as a first-year individual by the pale tips to its primaries. This may indicate that it is an inexperienced bird, and therefore didn’t think much of us when we were in its area. This bird, to my knowledge, has never been baited at this site, so there should be no reason to believe that it had been coerced or manipulated into landing on this woman’s head. This experience was all pure luck, and I felt very appreciative to be in the right spot at the right time.

About Books: An Exquisite Ancient Menagerie

Thu, 01 Jun 2017 00:00:00 GMT

During the Mesozoic Era (~252–66 million years ago) this area had numerous lakes and wetlands. It was also the location of several active volcanoes, which occasionally erupted as volcanoes will do. Sometimes an eruption would cause a pyroclastic flow, a rapidly moving deadly cloud of gas, ash, and debris that would devastate life in the area and lead to mass mortality. Many birds instantly fell dead into the lakes and were quickly covered by ash. These occurrences explain the abundance of detailed fossils from this region of China. Some unearthed slabs of shale contain multiple fossils of the same species of birds. The shales are so fine that many fossils are accompanied by a perfect mirror-image fossil when the rock is split. Photographs of these shale outcroppings look like tall piles of densely stacked books waiting to be pulled out and read. It is a fossil-a-palooza.

Today there are dozens of quarries in the area, and since the 1980s paleontologists have uncovered thousands of fossils. The detail captured in these fossils is breathtaking, and that is what is celebrated in Birds of Stone by Luis M. Chiappe and Meng Qingjin. Luis M. Chiappe is the vice president for research and collections at the Natural History Museum of Los Angeles County, where he directs the museum’s Dinosaur Institute. He is also an adjunct professor at the University of Southern California and one of the great “explainers” of the science of paleontology. Meng Qingjin is the Director of the Beijing Museum of Natural History and vice chairman of the Chinese Association of Natural Science Museums and the Beijing Zoological Society. He is almost always “in the field” and is one of the giants of Chinese paleontology.

Birds of Stone is a large format, sumptuous book filled with full color photographs of the fossils of the Mesozoic birds of the Jehol Biota. The high quality of the photographs is due to the efforts of Maureen Walsh and Stephanie Abramowicz, who spent weeks in China preparing and photographing the fossils. Many of the photographs are full page, with a number of two-page spreads. The accompanying text by the authors is thorough and fascinating. This text introduces the reader to many unique aspects of these ancient birds and what we can learn from the fossils. It is nothing less than an introductory course in Mesozoic ornithology and contemporary paleontology. Many of the birds found in the Jehol Biota are enantiornithines. Other species are ornithuromorphs, a more primitive group. The enantiornithines were an abundant and diverse group of Mesozoic birds. Thousands of fossils of these birds, more than 30 species, have been found in the Jehol Biota deposits. These Chinese enantiornithines ranged in size from that of a crow to something closer to a Western Sandpiper. Unlike modern birds, many enantiornithines had teeth, which gave some species quite a fierce look. The variety of dentition found in the fossils shown in Birds of Stone indicate that some species ate fruit, others caught fish or crushed seeds, and some probably probed in the mud for invertebrates.

Enantiornithines had clawed fingers on each wing, and like modern birds, they had alulas, the small group of feathers found at the bend of the wing that aid in flight. It used to be thought that enantiornithines could not fly well, but the evidence of the Jehol Biota fossils, as well as fossils unearthed elsewhere, indicates that some enantiornithines did achieve aerial competence, although their flight style may have been unlike that of modern birds. Some species may have flown, while others may simply have launched themselves from branch to branch. The feet of some species show that they could grasp a branch and perch; they even had a long hind toe like some modern birds. No fossil eggs of birds have been found from Jehol, and only one fossil embryo has been uncovered so far. Based on anatomical differences of adults, it has been theorized that some species laid small clutches of large eggs while other species laid large clutches of small eggs. You might be wondering if these birds sang. Because a syrinx is not present in any of these species, the vocalizations would not have been as complex as those of a warbler or thrush, but they likely made some kind of call like most non-songbirds do today. Overall, enantiornithines look more like modern birds than Archaeopteryx lithographica, but with a number of key differences.

The detailed pictures of feathers in some of the fossils (p. 21 and many other pages) certainly look like the feathers of modern birds at first glance, but again, there are some differences. There are many fossils in the Jehol of the primitive Confuciusornis sanctus. This large bird had a strong, massive toothless beak and likely ate tough seeds and fruit. Confuciusornis sanctus probably did not fly much but spent most of its life on the ground. What is most striking about this bird are the two, very long tail feathers that will remind you of a Fork-tailed Flycatcher or some species of motmot. But these feathers are not attached to a pygostyle, that fleshy and bony area at the end of the body sometimes colloquially known as the “Pope’s nose.” Furthermore, the shaft that runs the length of these long feathers looks more like a belt than a shaft. The feathers of many of these birds lack a shaft. Since fossils of some adult Confuciusornis sanctus have been found without these unique tail feathers, it has been suggested that this may be one of the earliest known examples of sexual dimorphism in birds.

Some of the fossils in the photographs in Birds of Stone are so detailed that they show the microstructure of the birds’ bones and allow us to age the specimens. As to the coloration of these species, paleontologists are now looking at the distribution of minute melanosome capsules in the fossils to indicate what areas of the body were darker than others. It is amazing what a wealth of information is contained in every shale slab.

Of course, life other than birds is also preserved in the Jehol Biota, and several examples are shown in Birds of Stone. Fossils from this area include plants, numerous frogs, fish, salamanders, and turtles. There are a number of fossils of mouse-sized mammals. There are also fossils of invertebrates, including many wonderfully preserved mayfly nymphs (Ephemeropsis trisetalis).

Birds of Stone is an eye-opening introduction to an actual Lost World of birds. The last third of this book is a thorough account of the early evolution of birds beyond those found in the Jehol. This includes the evolution of feathers in non-avian dinosaurs. What this book does not have is any artist’s paintings of what the living birds may have looked like. The visual focus is always on the actual fossils themselves and what they show us. The one exception is a simple painting of the Changyuraptor yangi, the “largest flying non-avian dinosaur” (p. 246), which because of its heavily feathered legs, looks like it “flew” with four wings. Imagine what that would look like in flight. Birds of Stone is a visual feast and one of the most beautiful books published on fossils, written by two experts in the field. In this book we are witness to another chapter in the evolution of the birds we are familiar with today.

Like no other fossils, the spectacular avifauna from the Jehol Biota has brightened our understanding of the lives of a thriving diversity of ancient birds, which study has transformed our knowledge about some of the earliest relatives of present day birds and has greatly clarified key aspects of the evolution of these remarkable animals. (p. 188)

Marj the Magnificent: A Tribute and Thank You to Marj Rines

Thu, 01 Jun 2017 00:00:00 GMT

Through the years, a number of Bird Observer field records editors assisted Mass Audubon’s Ruth P. Emery with the task of compiling bird records until 1989, when failing health made it impossible for Ruth to continue. In 1990, Marj Rines assumed an active role as bird record arbitrator and archivist for Bird Observer (as it was called by then). Shortly after taking on the responsibility of compiling and overseeing the validity of the journal’s printed field reports, Marj, who was considerably computer savvy, created a searchable, digital database for Massachusetts bird records that ultimately was to prove of immense value to editors, authors, and anyone quickly needing a local compendium of bird reports by date, locality, or observer. This contribution alone, to say nothing of her continual monthly sifting and sorting of statewide bird reports, made Marj Rines a practically indispensable resource for nearly three decades of bird recordkeeping for Massachusetts.

With this historical glimpse of bird recordkeeping in Massachusetts in mind, the Board of Directors and staff of Bird Observer, as well as the entire New England birding community, wish to salute Marj’s many contributions to Massachusetts ornithology, which include popularizing and helping raise birding in the Commonwealth to a new level. Good luck in whatever comes next Marj, but whatever you do, don’t stop birding!

Bird Observer would like to thank recently-retired members of the Board of Directors Elizabeth (Liz) Clark, Paul Fitzgerald, Carolyn Marsh, John Marsh, and Fay Vale for their support and many contributions to the journal and the organization.

Bird Sightings: January-February 2017

Thu, 01 Jun 2017 00:00:00 GMT

February was a mixed bag, from frequent snow to record warm temperatures. The temperature averaged 37°, five degrees above normal. The high of 73° on February 24 set a new record for the month of February, and Worcester also experienced an all-time high of 68° that day. Rainfall for the month totaled 3.22 inches. Snow turned to rain on February 7–8 bringing hazardous conditions that caused multiple road accidents. A blizzard on February 9 dumped as much as 18 inches of snow in some areas. Nantucket reported winds out of the northeast at 68 mph, and a burst of 55 mph was reported from the Blue Hills in Milton.

R. Stymeist

Front Cover: June 2017

Thu, 01 Jun 2017 00:00:00 GMT

Yellow Warbler taxonomy is complex and somewhat controversial, with 33 recognized subspecies that are divided into three groups: the Yellow Warbler, or aestiva group; the Golden Warbler, or petechia group; and the Mangrove Warbler, or erithachorides group. All three groups bear the names of what were originally described as separate species. The aestiva group is divided into six subspecies, the other two into 16 and 11 subspecies respectively. The northern limit of the aestiva group’s breeding range extends from the Aleutian Islands and most of Alaska through northern Canada to the shrubby edges of the tundra, then dips south of Hudson Bay and east to southern Labrador and all of Newfoundland. The range extends south to northern Georgia and west through Oklahoma to California—comprising about half of the United States—and extends south along the west coast to Baja California, and from Arizona to southern Mexico. Aestiva birds are migratory. This group winters from southern Baja and western Mexico south through Central America and in South America east of the Andes south to Bolivia. They spend the winter in scrubby wooded habitats, and frequently in mangroves. In Massachusetts, the Yellow Warbler is a widespread common migrant and breeder. Yellow Warblers arrive in late April and depart from late July to early August.

The other groups of Yellow Warblers are sedentary. The Golden Warbler group ranges from southern Florida through the West Indies and the Caribbean south to Venezuela; males have a chestnut-colored patch on the crown. The Mangrove Warbler group ranges from Baja California south through Central America and in South America in the west through central Peru; males have a chestnut-colored head. The Yellow Warbler is certainly one of the most diverse warbler species, but with DNA studies now available it would not be a surprise if ultimately it once again gets split into two or more species.

Yellow Warblers are usually monogamous, but sometimes also may be polygynous. They tend to be site faithful when breeding, and may mate with the same partners in successive years. Males sing from perches in shrubs or trees. The song is a series of short units that have been described mnemonically, as sweet, sweet, sweet, sweeter than sweet. Males deliver two basic patterns of song: one pattern is used for male-female communications, including mate attraction. The other pattern is for male-male communication, for example in territorial advertisement. A number of behaviors are involved in establishing a territory and attracting a mate. A male may fly in a circular pattern toward another warbler at its territorial boundary, may glide with wings and tail spread, or fly slowly with exaggerated wing beats holding its head up over its back. Chases are frequent and sometimes end in fights. A stationary display involves a spread tail and lifted wings.

In our area, Yellow Warblers prefer to nest in wet thickets, especially thickets containing willows, and their habitat includes most disturbed successional habitats. The nest is a deep cup built by the female in a fork in a shrub or tree. It is constructed of bark and grasses and covered in fine gray fibers. The clutch is variable but usually consists of three to five eggs that can vary in color: grayish white to pale green or blue and spotted and blotched with brown or olive around the large end of the egg. Only the female develops a brood patch and she alone incubates the eggs for the 10 to 12 days until hatching. The altricial chicks are helpless upon hatching, and are covered with natal down and their eyes are closed. The female does the all brooding for the eight to ten days until fledging. The female may give a distraction display if the nest is approached. Both parents feed the young, which may remain with the parents as long as three weeks after fledging.

Yellow Warblers feed upon a wide variety of insects and insect larvae. They primarily forage by gleaning leaves, but also hawk flying insects and snatch prey from leaves by hovering. They occasionally eat fruit.

Yellow Warbler nest predators include snakes, mammals such as squirrels, weasels, and raccoons, and birds such as crows and jays. In some areas, they suffer from cowbird nest parasitism. However, if cowbirds lay eggs early in the nesting cycle, Yellow Warblers may cover the clutch and start afresh, producing a multi-tiered nest effect. One nest had six tiers and 11 cowbird eggs! They also may desert their nest and presumably rebuild elsewhere.

As a primarily long-distance nocturnal migrant, many are killed in collisions with buildings or towers. Habitat alteration, including cattle grazing, is a problem, but the Breeding Bird Survey data indicate that their overall population is stable, even though there are different regional trends. For example, there has been a decline in the Pacific rain forest area, and increases in southern New England and the Great Lakes area. Thus it appears that with its vast breeding area, this delightful little warbler is reasonably secure.

William E. Davis, Jr.

At a Glance: June 2017

Thu, 01 Jun 2017 00:00:00 GMT

Can you identify the bird in this photograph? Identification will be discussed in next issue's AT A GLANCE.

At a Glance: April 2017 Revealed

Thu, 01 Jun 2017 00:00:00 GMT

A cursory look at the mystery bird reveals a hefty gull with a stout bill, a full-chested look, relatively long, pink legs (visible in the online version), and an overall pale or frosty appearance. This bird is clearly a large gull, not one of the smaller species such as Bonaparte’s Gull. Also of note is the seemingly anomalous presence of dark (blackish or brownish) primaries and what appears to be a dusky tail band visible below the bird’s left wing. Finally, the gull has a neat black tip to an otherwise pale bill. This combination of characters represents an example of the type of conundrum hinted at in the opening paragraph.

So, what are the issues and what are the options surrounding the identification of the mystery gull? First, the frosty appearance, robust size, head shape, and dark-tipped bill pattern of the mystery gull suggest the possibility that it could be a Glaucous Gull, except that it clearly has dark primaries and a seemingly dark tail band. Glaucous Gulls are classic white-winged gulls that typically have immaculately white primaries. Likewise, most Iceland Gulls occurring in Massachusetts and elsewhere on the northeastern coast of North America have pale or white wing tips, or else have at least some gray spotting or charcoal coloration in the primaries. However, there seems to be little question about the degree of darkness on the wing tips of the pictured gull. Where does this leave us?

The reader is now confronted with a classic mystery gull. Given the features at hand, there are two likely options. The bird might be abnormally frosty due to a genetic condition, or else it might be a hybrid. If the gull is a hybrid, the most likely possibility is a Glaucous x Herring cross. Such hybrids are fairly regular in areas where Glaucous Gulls and Herring Gulls coexist in Canada and elsewhere; when they hybridize, they are sometimes called Nelson’s Gulls, a name at one time applied to such hybrids occurring in the Bering Sea, which were then thought to be a distinct species. If the bird were expressing a genetic anomaly, it would most likely show either a form of leucism or schizochromism that would somehow give the bird an abnormally pale appearance to its body plumage, yet not affect the bill or wing tip coloration. Given these choices, hybridism is the more likely possibility, in which case the mystery gull is likely a cross between a Glaucous Gull and a Herring Gull. Regardless of its identity, such individuals are always interesting, even if they can’t always be definitively identified.

The author photographed this gull at Eastern Point, Gloucester, on February 7, 2009.

Wayne R. Petersen

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Thu, 01 Jun 2017 00:00:00 GMT

In this issue:

Hot Birds: June 2017

Thu, 01 Jun 2017 00:00:00 GMT

At least two and possibly four or more White-faced Ibis spent the latter half of April into early May in a large flock of Glossy Ibis in Essex County. Reports came in from at least three locations in Ipswich plus one from Wenham Lake. Nathan Dubrow took the photo above.

A one-day wonder, a male Painted Bunting appeared at a feeder in Huntington. The homeowner welcomed birders but the bird was less accommodating, never seen again after the first day. Surprisingly, given Hampshire County’s very few prior records of this species (maybe only one?), this is the second record for the town of Huntington: another male spent roughly the last week of November and first week of December in 2006 here as well! Lois Richardson took the photo above.