August 2015

Birding Morris Island and Vicinity, Chatham, Massachusetts

Sat, 01 Aug 2015 00:00:00 GMT

Causeway and Tom’s Neck

Now that you have parked, do not rush down to the water. The thickets, trees, and edges of the parking lot often hold excellent birds. Check every inch of the parking area, including the small medians between parking spaces. The pines along the visitors center often hold a nice mixed flock in the fall. In September, for example, Philadelphia Vireos and Yellow-bellied Flycatchers are often quite easy here. On a late September afternoon in 2010, for example, a brief pishing session in the parking lot rewarded me with a Lark Sparrow and a White-eyed Vireo in the same binocular field.

Once you have tapped out the parking lot, you have two possible routes down to the beach. The first route is a short, rocky trail near the entrance gate. This trail ends on a small platform with stairs, which overlooks the beach and marsh to the north. Ospreys breed in this marsh, and the platform is a nice spot to observe them. The marsh itself is great to explore; in the past, it has produced Clapper Rails and Saltmarsh, Nelson’s, and Seaside sparrows. In winter, this marsh is one of the better places in Chatham to find Eastern Meadowlarks and Ipswich Savannah Sparrows. In the spring and summer, the marsh is a great spot for wading birds; check it carefully for Little Blue Herons and Tricolored Herons. The marsh is also one of the better places in Chatham for large flocks of Canada Geese, which should be checked carefully for Cackling and others during migration. Finally, Savannah Sparrows and sometimes Prairie Warblers breed in the dunes and bushes on the edges of the marsh; both often sing in great light just off the observation platform. Sea watching from the platform can be rewarding, as you can see across the spit to the ocean. Gannets, jaegers, Razorbills, and several species of shearwaters are possible here in appropriate seasons.

The second route down to the water is past the restrooms and the refuge volunteer dorms. It follows a boardwalk past a set of birdfeeders. If the feeders have seed in them, this is a great spot during migration to see birds such as Lincoln Sparrows, Swamp Sparrows, Indigo Buntings, Eastern Towhees, and rarely, Clay-colored and Vesper sparrows. Past the feeders, the boardwalk continues, with offshoots to two overlook areas. On clear days you can see over Chatham Harbor to South Beach from these overlooks. Scanning the beach and water in the cove can be rewarding, with numerous sea ducks possible in all seasons, as well as shorebirds on South Beach. This southern cove of Chatham Harbor often holds the largest concentration of summering sea ducks in the state, including all three scoter species, Common Eiders, Long-tailed Ducks, and a handful of Red-breasted Mergansers.

Townsend’s Solitaire

Once past the overlooks, you will reach a long staircase. Walk down this staircase—leave your shoes halfway down if you would like them back after the tide comes in—to the beach. Birding any farther than the stairs is difficult during mid-to-late incoming or high tides because the beach is usually totally submerged. If the tide is low enough and you have reached the beach, start walking southwest, or to the right if you are facing the water. The walk is pleasant and safe when you have checked the Chatham Stage Harbor tide chart in advance and figured out how many hours you will have before high water eliminates the beach and the return route. At a mid- outgoing tide, you will probably have around four hours; at low tide you will have a couple of hours; when the tide starts to rise, be aware of how quickly it comes in. Plan accordingly!

As you continue down the beach, watch for Least and Spotted sandpipers just off the stairs during migration. In a quarter mile or less, you will come to an unmarked opening in the dunes on your right; continue past this private property and you will reach a refuge trail sign with an arrow pointing right. Taking this trail brings you into what I refer to as the maritime forest. The maritime forest trail loops through a stand of pines and thickets with breeding Pine Warblers and Eastern Towhees. The forest can hold quite a few migrants during migration, and both crossbill species turn up during incursion years. During spring and fall migration, pay careful attention to the few groves of deciduous trees mixed into the pine grove, as these usually hold the largest flocks of mixed species.

Seaside Sparrow

Follow the signs to stay on the refuge, and you will reach the salt pond. This is your best shot for dabbling ducks on the island. I’ve had Blue- and Green-winged teals, Northern Pintail, and others here. When it is not dry, the pond often has both yellowlegs species and other shorebirds. Green Herons and Killdeer often wander around the pond’s edges, and Tree Swallows nest in the surrounding boxes.

Once you have walked around the pond, walk along the trail back out to the beach and head southwest. The beach will come to a corner, around which you should continue. This corner is one of the better spots to witness morning flight on the island, as reorienting migrants often rocket off North Monomoy back to the mainland. In fall, you can get Dickcissels here if you know their flatulent flight call. At the lower tides, the spartina grasses along this stretch hold breeding Saltmarsh Sparrows in the spring and summer. This area is also good to check for Seaside Sparrows in spring and fall migration, and Nelson’s Sparrows in fall. Once you have checked the spartina, look across the water. This is the best location on Morris Island to scan North Monomoy Island. Starting in late June, Hudsonian and sometimes Marbled godwits are usually easy pickups here. Large flocks of peeps are also present, though difficult to identify unless it is an exceptionally clear day. While scanning North Monomoy, keep an eye out for herons. The island has a large colony of wading birds; you may pick out a Glossy Ibis or, if you are lucky, a Yellow-crowned Night Heron.

White-eyed Vireo

After you have scanned North Monomoy, continue down the beach. At lower tides, you will come to Morris Island’s best mudflats. Though shorebird numbers will not compare to South Beach or North Monomoy, there are often decent flocks here. Both godwits, Whimbrels, American Oystercatchers, and large flocks of peeps are possible here. Given that you will be so close to the birds, make sure to check every peep for rarities like Red-necked Stint and Curlew Sandpiper! Continue down the beach, and you will walk past large dunes on your right. These dunes often have breeding Horned Larks and occasionally a Bank Swallow colony. If you decide to walk to the end of the beach—approximately two miles—you will reach the mouth of Stage Harbor. The harbor mouth can be a great spot for Common, Roseate, Forster’s and sometimes Arctic terns, and the harbor itself can hold a Barrow’s Goldeneye or two, as well as a large flock of Canada Geese.

You have two options when walking back to your vehicle. One is to go back in the direction you came. Often the birds on the way back, especially flocks of shorebirds, are completely different from the flocks you saw on the walk out. The second option is to walk back along Stage Harbor. There are often small flocks of peeps here, and this habitat is your best bet for species like Buff-breasted and Pectoral sandpipers. After about a half mile or less of walking, there is a cut-through trail back to the beach, where you can continue to the main stairs.

Outside of the refuge parking area, the neighborhoods on the island can be exceptionally birdy and include some of the best habitat on the island. That being said, the streets in these neighborhoods are private ways, not public ones. You should bird along these streets only with permission of the residents.

Morris Island Causeway

Just down the hill from Morris Island is the causeway. This area offers what may possibly be your best shot at a mega-rare bird in the area. The causeway’s scrubby habitat has attracted many rare birds, including Western Kingbirds, Loggerhead Shrikes, and once a Eurasian (!) Kestrel. Parking is legal along the entire length of the causeway. Though there are no restricted areas for walking, the habitat is sensitive and should not be trampled. There are several open areas near the hill up to Morris Island where you can access the habitat just off the causeway. Walk out through these openings toward the ocean (not the cove), and walk along the edge of the pines and bushes. The Morris Island causeway is best in the fall, especially in mid- to late- October, when massive flocks of Yellow-rumped Warblers, sometimes numbering in the hundreds, descend on the cedars along the road. Often other species are mixed into the smorgasbord, so check these flocks carefully. During birdy fall days on the causeway, Orange-crowned Warblers are likely, sometimes with several present. The surrounding thickets and berry bushes often hold hidden gems, including White-eyed Vireos and Yellow-breasted Chats. Virtually any Massachusetts passerine is possible here during fall migration.

Willet

Once you pass the trees and bushes, both sides of the Morris Island causeway include salt marsh habitat. Clapper Rails have been documented here in past years, though they are not annual. Little Blue and Tricolored herons have been seen here, so check any large mixed flocks of Snowy and Great egrets. American Oystercatchers and Willets are often present on the west side of the causeway, often with a nice assortment of dabbling and sea ducks.

Tom’s Neck

After you have birded Morris Island and the causeway, continue down Morris Island Road away from the island. You will round a corner and, in a quarter mile or less, come to Tom’s Neck. Tom’s Neck is a large plot of conservation land that stretches between Morris Island Road and Bridge Street. There is one loop trail in Tom’s Neck, and parking is legal on the road. Look for the Chatham Conservation Lands sign, and walk right in from there. During wet weeks and high tides, Tom’s Neck can be flooded and inaccessible. If you walk the trail, high boots are often necessary due to water and mud.

Osprey

Before entering Tom’s Neck, bird the massive thickets on the road in front of the trail. As with the causeway, this area is best during fall migration. These thickets often hold decent numbers of birds, including specialty migrants like Philadelphia Vireos and Yellow-breasted Chats. During spring and summer, Willow Flycatchers and Northern Bobwhites breed in Tom’s Neck, and from the road you can usually hear them singing. The trail has several small groves of trees and excellent thickets. The height of the thickets makes it difficult to see birds; however, the caliber of the habitat makes this walk worthwhile.

Winter: December to February

Winter in the Morris Island area can be exciting and rewarding. Half-hardys such as Gray Catbirds, Hermit Thrushes, and Eastern Towhees are present here all winter, with rarer winter species like Yellow-breasted Chats and Brown Thrashers possible. During incursion years by winter finches, the large groves of pine trees in the area can attract good-sized crossbill flocks, and large flocks of redpolls often forage in the dunes. Given the area’s geography, virtually any winter finch is possible as a flyover during big years, and Bohemian Waxwings are more than possible. Check thickets on the island and causeway carefully, as late warblers such as Ovenbirds can sometimes be present well into December.

Sea watching can be quite entertaining, with flocks of Razorbills, Black-legged Kittiwakes, and Northern Gannets all probable. Sea ducks, loons, and grebes are all common here, and a concentrated effort can occasionally produce a Dovekie or late Manx Shearwater (into late December).

Spring Migration: March to May

Though in my opinion, spring migration in the Morris Island area is less productive than fall migration, spring on Morris Island can be fun. On decent migration days there is a definite and noticeable morning flight at dawn; however, finding a flight line for the majority of the birds can be difficult, as there really is not a concentrated flight area. Cover the maritime forest trail and dunes thoroughly, and look for large flocks of sea ducks that remain in the cove. Sea watching isn’t as productive as later in the summer and fall, though you may get Parasitic Jaegers in late May. Watch for Black Skimmers in late spring because they breed on Monomoy, and from Morris Island you may occasionally see them feeding.

Breeding Season: June and July

Morris Island holds a typical assortment of Cape Cod’s breeding birds. Aside from the usual suspects, local specialties include Willow Flycatchers, Prairie Warblers (not annual), Killdeer, Piping Plovers, American Oystercatchers, Least Terns, and Green Herons (not annual).

Autumn shorebird migration is just beginning, so carefully check the North Monomoy flats for flocks of shorebirds, which often include a handful of Hudsonian Godwits. You can see seabirds, most likely Sooty Shearwaters, from shore. Great, Cory’s, and Manx shearwaters are also possible here in June and July, though usually outnumbered by Sooties. You can see Parasitic Jaegers in decent numbers on some days, though they are usually more visible from nearby Chatham Light.

Fall Migration: August to November

Fall migration is my favorite season to bird the Morris Island area. On good migration days, the island can be dripping with migrants, with virtually every inch of habitat holding mixed flocks. Nearly all Massachusetts passerine birds are possible here in fall, and the island produces mega-rarities with some regularity. Shorebird migration peaks between late July and late August, with thousands of birds often visible on North Monomoy. September is one of the better months for sea watching, with four shearwaters, jaegers, and Wilson’s Storm Petrels all possible.

eBird

The Morris Island area is covered by three eBird hotspots. The URLs for specific hot spot pages are:

Monomoy NWR—Morris Island: http://ebird.org/ebird/hotspot/L270936
Morris Island Causeway, Chatham: http://ebird.org/ebird/hotspot/L711450
Tom’s Neck Conservation Land: http://ebird.org/ebird/hotspot/L1072688

Ryan Schain was born and raised in Monmouth County, New Jersey, on the Jersey shore. He began birding around age five or six and spent his adolescent years birding on Sandy Hook in Raritan Bay. In 2005 at age 18, Ryan moved to Boston for college, where he has lived ever since. When he is not birding urban Boston migrant traps, Ryan is birding around his parents’ house in Chatham on Cape Cod. His favorite local patches are the Fenway in Boston and Morris Island in Chatham.

Winter Quarters and Migration Routes of Common and Roseate Terns Revealed by Tracking with Geolocators

Sat, 01 Aug 2015 00:00:00 GMT

Geolocators

Geolocators contain a clock and a light sensor that records light intensity every two minutes. By plotting the changes in light intensity, the times of sunrise and sunset on each day can be determined. The time of sunrise or sunset identifies the longitude, and the length of day or night on any specific date identifies the latitude. Geolocators also contain a battery and a computer chip that can store data for up to two years. When the data are downloaded, they provide a record of the location of the bird twice each day throughout the study period.

Despite their utility, geolocators have two major disadvantages. The first is that they store but do not transmit data, so each marked bird must be recaptured in order to download the stored location data. The second is that the location estimates are imprecise. Cloudy weather and other factors that reduce the intensity of light reaching the geolocator lead to errors in the estimated times of sunrise and sunset, and hence errors in the derived estimates of latitude and longitude. In our work with terns, uncertainty in estimates of longitude is typically about ±1º, or about ±100 kilometers in the east-west direction at the Equator and ±60–70 kilometers at mid-latitudes (Mostello et al. 2014).

Uncertainty in estimates of latitude is greater than in estimates of longitude, and increases progressively at dates close to the spring and autumn equinoxes and at latitudes close to the Equator. At the equinoxes, day length is the same everywhere on Earth and latitude cannot be estimated at all; close to the Equator, day length varies very little with latitude, so that estimates of latitude may be inaccurate by 10º (± 1000 km) or more. If a bird remains at the same location for weeks or months, statistical averaging allows that location to be determined fairly precisely. When a bird is traveling, errors in individual fixes can be large and the exact track cannot be determined.

Stopovers and Wintering Areas
		Common Terns			Roseate Terns
Area	Coordinates	Autumn	Spring	Winter	Autumn	Spring	Winter
A. Cape Cod	41–42º N, 70–71º W	11			6
B. Cape Hatteras	34–36º N, 74–76º W	4	3
C. NE Caribbean	18–20º N, 64–71º W	3	0		6	5
D. NW Venezuela/Aruba	12–13º N, 68–71º W	1	0	1	1	1
E. Trinidad	10–11º N, 61º W	4	0		0	0
F. Suriname	6–7º N, 54–56º W	5	0	1	4	0	1
G. French Guiana	5–6º N, 51–52º W	2	0		0	0
Brazil:
H. Pará	1º S, 46–49º W	4	4	1	4	4	1
I. Maranhão	3–4º S, 42–45º W	3	1		2	0
J. Céara/Rio Grande do Norte	4–5º S, 37–40º W	1	1		0	0
K. Alagoas/Sergipe/Bahia	10–17º S, 36–39º W	3	2	2			4
L. Espíritu Santo	19–21º S, 40–41º W	3	1	2
M. Lagoa do Peixe	30–34º S, 50–53º W			3
N. NE Argentina	36–40º S, 57–58º W			1

Table 1. Stopover and wintering areas of 11 Common and 6 Roseate Terns. Each entry for a stopover area indicates the number of birds that stopped there. Zero indicates that one or more birds passed through the area without stopping. NE Caribbean includes Haiti, the Dominican Republic, Puerto Rico and the Virgin Islands. The only Common Tern that reached Argentina spent part of the winter at the Lagoa do Peixe and alternated between these locations; it is included in this table for area N. Two Roseate Terns that spent the early part of the winter in area K moved to area J in February (Figure 2); they are included in this table for area K.

Tracking Common and Roseate Terns

During the 45 years we have studied and conserved the Common and Roseate terns that breed in Massachusetts, we have been repeatedly frustrated by the paucity of data on these birds in their winter quarters, where they spend about half the year. Until 2007, most information about the migrations and wintering areas of both species had been gleaned from banding recoveries, which were few and scattered, and whose occurrence usually depended on the unlikely combination of a bird dying in an accessible place and being found by an interested person. Band recovery data had indicated that both species migrate through the West Indies to winter on the north and east coasts of South America (Nisbet 1984, 2002), but little was known about dates and routes of migration or the precise locations of stopover and wintering sites. Information was particularly sparse for the Roseate Tern, which had rarely been encountered anywhere in South America, so that it had been almost impossible to devise conservation measures for this endangered species on its winter range.

When geolocators small enough to be carried by terns became available in 2007, we obtained 20 geolocators, weighing 1.5 grams each, from the British Antarctic Survey and attached them to custom-made plastic leg flags (Figure 1). We put the devices on 10 adults of each species that we caught on nests at Bird Island, Marion, Massachusetts. In 2008 we found six Common Terns and four Roseates that returned, retrieved nine geolocators, and obtained valuable data from seven of them. However, we were concerned at the low rates of return—40% for Roseate Terns and 60% for Commons, versus 83% and 90% expected, respectively, based on average survival rates for each species (Nisbet 2002; Spendelow et al. 2008). We decided to discontinue the study until smaller devices were developed. In 2009, geolocators weighing only 1.0 gram became available, and we repeated the study, attaching devices to 10 more adults of each species. Combining the results of the two years, we retrapped 13 of 20 Common Terns and nine of 20 Roseate Terns, and obtained useful data from 11 Commons and six Roseates.

After downloading and analyzing the stored data using software supplied by the British Antarctic Survey, we were confronted by a huge volume of data: 11,084 paired estimates of latitude and longitude. To date, we have published three papers in scientific journals (Nisbet et al. 2011a, 2011b; Mostello et al. 2014), and we are planning at least one more. Ours was one of the first two studies to use geolocators to track terns, the other being the groundbreaking work on the migration of Arctic Terns from Greenland to the Antarctic and back (Egevang et al. 2010).

Fig. 2. Migration routes and winter quarters of Common and Roseate terns. The main areas used for stopovers and wintering are marked with letters keyed to those in Table 1. Filled areas include locations used for long periods during the winter. Within each marked area, each bird usually stayed within a small range of longitudes and latitudes.

Winter Quarters

Our tracking results revealed that Roseate Terns spent the winter at three locations on the north and east coasts of South America, spanning about 4,000 kilometers of coastline from Suriname to eastern Brazil (Table 1, Figure 2). Common Terns wintered over an even wider area, extending along about 8,000 kilometers of coastline from northwest Venezuela to northeast Argentina (Table 1, Figure 2). Despite the enormous scatter of these birds during the winter, each returned to Bird Island and nested within a few meters of its previous year’s location.

All the birds that wintered on the north coast of South America could be located fairly precisely—within 20–120 kilometers—depending on length of stay. Because the coast runs from west to east, the locations could be determined from longitudes alone despite proximity to the Equator. The Common Terns that wintered in southern Brazil and northeastern Argentina (areas M and N in Figure 2) could be located with similar precision using both latitude and longitude data. The locations of birds that wintered in eastern Brazil north of 20º S (areas K and L) were determined less precisely, because latitude estimates were unreliable and longitude estimates could correspond to a fairly wide range of locations as the coast runs from north-northeast to south-southwest.

All our birds appeared to have been stationary for weeks or months during the winter, because estimates of both latitude and longitude were stable over these long periods, within the expected range of errors. However, six of the nine birds that wintered in eastern Brazil shifted from one stable location to another once or twice during the winter, based on consistent shifts in average longitude by 1–3º. Three Common Terns moved from eastern to southern Brazil (areas K and L to area M) late in the season but spent most of the winter in eastern Brazil (Figure 2). Another Common Tern moved twice from area M in southern Brazil to and from area N in northeastern Argentina. Two Roseate Terns moved from eastern Brazil (area K) to the north coast in February (area J).

Most of these wintering locations had been known or suspected from previous banding recoveries or field studies (Hays et al. 1997, 1999), although it was surprising to find that one Common Tern spent the entire winter as far west as northwest Venezuela (area D, Figure 2). It was also surprising that only one of our 11 Common Terns traveled as far south as northeast Argentina (area N), because this is an area of major winter concentration for the species (Sapoznikow et al. 2002); many Common Terns banded there have been found nesting at Bird Island and other locations in the northeastern United States (Figure 2).

Geolocators on four birds—one Roseate, three Commons—stopped collecting data between January and March, but the remaining 13 devices yielded detailed information on the time the birds spent in their winter quarters. The five Roseate Terns for which we had data spent five or six months (156–186 days) at their wintering sites, much longer than at their breeding sites (73–111 days) or their combined staging and breeding periods in North America (about 120–140 days). The eight Common Terns for which we had data were much more variable in their timing, spending three to eight months (87–235 days) in their winter quarters (Table 1). For six of these birds, length of residency in the winter quarters exceeded that in North America.

Migration Routes and Stopover Sites

We obtained a wealth of new information on migration routes and stopover locations (Table 1, Figure 2). All 17 birds of both species spent most or all of the postbreeding period around Cape Cod and the Islands (area A) from late June or July until they departed on southward migration in August–October. All then made long, direct flights across the western North Atlantic Ocean to the West Indies, most of them making landfall in the vicinity of Puerto Rico or the Dominican Republic. Common Terns made this crossing in two to three days, whereas Roseates traveled faster, completing the flight in one and half to two days.

In addition to Cape Cod, Roseate Terns used three major staging areas in autumn (Table 1, Figure 2): the northeastern Caribbean (area C, mainly in Puerto Rico or the Virgin Islands), a small area in northwest Suriname (area F), and a small stretch of coast in northern Pará, Brazil (area H). All the Roseate Terns that passed through these areas either stopped over for periods of 5–24 days or remained for the entire winter (one each in Suriname and Pará; Table 1).

The behavior of Common Terns was much more variable. Four birds staged in the vicinity of Cape Hatteras (area B) before crossing to the West Indies, and only three of the 11 birds stopped over in the northeastern Caribbean. Common Terns then used at least seven distinct stopover areas along the north coast of South America (Table 1).

On spring migration, there were few stopovers (Table 1, Figure 2). All the Roseates and four of the Commons that spent the winter on the east coast of South America staged in northern Pará (area H), at exactly the same locations they used in the autumn; none of these birds stopped again anywhere in South America (Table 1).

All the birds retraced their autumn migrations along the north coast of South America as far as the eastern Caribbean, but most then followed spring tracks farther to the west of their autumn tracks. Ten Common Terns continued west-northwest across Hispaniola or eastern Cuba, northwest through the Bahamas and then northeast, parallel to the North American coast but well out to sea, close to or outside the edge of the continental shelf, until they reached Cape Cod. One Common Tern differed from all the others in retracing its autumn route, flying from Venezuela through the eastern Caribbean and then directly north to Cape Cod, without passing west of longitude 71º W.

Three Common Terns stopped near Cape Hatteras (area B, Figure 2) for a few days, although they appeared to spend most of this time at sea, sometimes far from shore. Otherwise, none of the Common Terns stopped anywhere for more than a day, although five birds traveled slowly and spent several days moving through the Bahamas.

Three Roseate Terns stopped over in Puerto Rico or the Dominican Republic (area C, Figure 2) for 8–11 days on spring migration, but their subsequent behavior was unexpected. They traveled slowly and erratically over the North Atlantic Ocean, arrived at Bird Island later than usual, were underweight when we trapped them, and did not acquire mates. It seems likely that their spring migration was impaired by the geolocators, although there was no sign that their autumn migration had been affected. We do not understand the difference.

Timing of Migration

The dates of migration included several surprises. The seven female Common Terns all left Cape Cod on southward migration between August 1 and 22 (Nisbet et al. 2011b); one of these birds stopped over at Cape Hatteras and did not leave North America until late September. The other six females then traveled quite fast: five reached Suriname and four reached Brazil before the end of August; four arrived in their final winter quarters (one in Suriname and three in Brazil) between August 21 and September 10. This early migration was unexpected, because Common Terns remain abundant around Cape Cod until mid-September, with significant numbers remaining through October and small numbers into November. Also, adult Common Terns provide prolonged post-fledging parental care: juveniles are accompanied and fed by their parents throughout August and into early September. Our results suggest that after the females leave, males stay behind to care for the juveniles. The four male Common Terns departed over a nearly two-month span between August 12 and October 4; we do not know if they were accompanied by juveniles at the time of departure.

Common Tern. (Photograph by Sandy Selesky).

The autumn migrations of the seven Common Terns that did not migrate directly to winter quarters were extremely varied in their timing. Some birds made prolonged stays in staging areas, for example: 48 days at Cape Hatteras, 23 days in Puerto Rico, 61 days at Aruba, 49 days in Suriname, and—the same bird—49 days in French Guiana. Arrival dates in the winter quarters ranged from September 30 to December 17. One female that had reached Bahía, Brazil (area K) on September 6 stayed there until November 23, then arrived at her final wintering site at Lagoa do Peixe, Brazil (area M), on November 29 (Table 1). Roseate Terns were much less varied in their timing. They started south between August 28 and September 14 and reached their wintering sites between October 3 and November 2.

Spring migration was faster and more tightly scheduled. All the Roseate Terns left their winter quarters between April 7 and 23, and all but two Common Terns left between April 1 and 12. The exceptions were one Common Tern that moved to its staging site at Pará in March and left there on April 22, and one that left its wintering site in Venezuela on April 26. Most of the Common Terns traveled extremely rapidly, with transit times to Cape Cod as short as eight and nine days from Brazil, seven days from Venezuela, and six days from Suriname. Birds that started from Brazil and Suriname flew far west of a direct line to Cape Cod, so their average travel speeds must have been in the range of 500–800 kilometers per day, including time spent feeding and resting. The Roseate Terns also traveled rapidly west as far as the Caribbean, but three of them delayed on the final leg of their journey. All birds of both species spent 5–15 days in the vicinity of Cape Cod before settling at Bird Island, but it was not clear if they used this as a staging area as they did in the autumn.

Contributions to Conservation

The primary goal of our study was to help devise measures to conserve both species of tern by gaining more knowledge about their locations and behavior away from the breeding area, where most mortality is thought to occur (Nisbet 2002, 2014). This knowledge was especially needed for the Roseate Tern, an endangered species that was declining for unknown reasons when we planned the study. Most of the locations where our Roseates wintered remained undiscovered, and nothing was known about their ecology or limiting factors in the winter quarters.

Although we obtained data for only six Roseates, the results added enormously to our knowledge of the species. We identified four major areas used for both wintering and migratory stopovers—the northeastern Caribbean from the Dominican Republic to the Virgin Islands, the northwest coast of Suriname, a small area in northern Brazil, and a larger area on the east coast of Brazil (areas C, F, H and K)—and the dates when they were present. This information is already being used to plan focused field studies— spearheaded by the Canadian Wildlife Service—to study Roseates in those areas.

Many factors that may affect Roseate Terns—and Common Terns—have been identified, including overexploitation of fisheries, offshore oil development, pollution, degradation of mangroves and coral reefs, and development of coastlines for recreation and building of vacation homes (Mostello et al. 2014). We hope that focused field studies in the places we have identified as important for these species will help to determine if and how terns are being impacted. For example, all of the birds in our study used Cape Cod for long periods in autumn, confirming earlier indications that Cape Cod is a major staging area for both Common and Roseate Terns. Studies are currently under way to determine if and how recreational activities on Cape Cod are affecting terns there, to serve as the basis for conservation measures. We hope that our study of migration routes and winter quarters will serve in the same way as the first step toward conservation actions in places outside North America where terns concentrate.

References

Bairlein, F., D. R. Norris, R. Nagel, M. Bulte, C. C. Voigt, J. W. Fox, D. J. T. Hussell, and H. Schmaljohann. 2012. Cross-hemisphere Migration of a 25 g Songbird. Biology Letters 8: 505–507.
Beason, J. P., C. Gunn, K. M. Potter, R. A. Sparks and J. W. Fox. 2012. The Northern Black Swift: Migration Path And Wintering Area Revealed. Wilson Journal of Ornithology 124(1): 1–8.
DeLuca, W. V., B. K. Woodworth, C. C. Rimmer, P. P. Marra, P. D. Taylor, K. P. McFarland, S. A. Mackenzie and D. R. Norris. 2015. Transoceanic Migration by a 12 g Songbird. Biology Letters 11(4): DOI: 10.1098/rsbl.2014.1045
Egevang, C., I. J. Stenhouse, R. A. Phillips, A. Petersen, J. W. Fox and J. R. D. Silk. 2010. Tracking of Arctic Terns Sterna paradisaea Reveals Longest Animal Migration. Proceedings of the National Academy of Sciences of the USA 107 (5): 2078–2081.
Hallworth, M. T., T. S. Sillett, S. L. Van Wilgenburg, K. A. Hobson and P. P. Marra. 2015. Migratory Connectivity of a Neotropical Migratory Songbird Revealed by Archival Light- level Geolocators. Ecological Applications 25: 336–347.
Hays, H., J. DiCostanzo, G. Cormons, P. D. T. Z. Antas, J. L. X. do Nascimento, I. do L. S. do Nascimento, and R. E. Bremer. 1997. Recoveries of Roseate and Common Terns in South America. Journal of Field Ornithology 68(1): 79–90.
Hays, H., P. Lima, L. Monteiro, J. DiCostanzo, G. Cormons, I. C. T. Nisbet, J. E. Saliva, J. A. Spendelow, J. Burger, J. Pierce and M. Gochfeld. 1999. A Nonbreeding Concentration of Roseate and Common Terns in Bahia, Brazil. Journal of Field Ornithology 70(4): 455–464.
Heckscher, C. M., S. M. Taylor, J. W. Fox and V. Afanasyev. 2011. Veery (Catharus fuscescens) Wintering Locations, Migratory Connectivity, and a Revision of Its Winter Range using Geolocator Technology. Auk 128(3): 531–542.
Hobson. K. A. and K. J. Kardynal. 2015. Western Veeries Use an Eastern Shortest-Distance Pathway: New Insights to Migration Routes and Phenology Using Light-Level Geolocators. The Auk 132(3): 540–550.
Mostello, C. S., I. C. T. Nisbet, S. A. Oswald and J. W. Fox. 2014. Non-breeding Season Movements of North American Roseate Terns Sterna dougallii Tracked with Geolocators. Seabird 27: 1–21.
Nisbet, I.C.T. 1984. Migration and Winter Quarters of North American Roseate Terns as Shown by Banding Recoveries. Journal of Field Ornithology 55(1): 1–17.
Nisbet, I. C. T. 2002. Common Tern Sterna hirundo. No 618 in The Birds of North America (eds., A. Poole and F. Gill). The Birds of North America, Inc., Philadelphia, PA.
Nisbet, I. C. T. 2014. Roseate Tern (Sterna dougallii) in The Birds of North America Online (A. Poole, Ed.). Ithaca: Cornell Lab of Ornithology: http://bna.birds.cornell.edu/bna/species/370
Nisbet, I. C. T., C. S. Mostello, R. R. Veit, J. W. Fox and V. Afanasyev. 2011a. Migrations and Winter Quarters of Five Common Terns Tracked using Geolocators. Waterbirds 34(1): 32–39.
Nisbet. I. C. T., P. Szczys, C. S. Mostello and J. W. Fox. 2011b. Female Common Terns Sterna hirundo Start Autumn Migration Earlier Than Males. Seabird 24: 103–106.
Sapoznikow, A. Vila, J. Lopez De Casenave and P. Vuillermoz. 2002. Abundance of Common Terns at Punta Rasa, Argentina: a Major Wintering Area. Waterbirds 25(3): 378–381.
Spendelow J. A., J. E. Hines, J. D. Nichols, I. C. T. Nisbet, G. Cormons, H. Hays, J. J. Hatch and C. S. Mostello. 2008. Temporal Variation in Adult Survival Rates of Roseate Terns During Periods of Increasing and Declining Populations. Waterbirds 31(3): 309–319.

Ian Nisbet is a former Director of Science at the Massachusetts Audubon Society. He has been a member of the Nuttall Ornithological Club since 1975 and was appointed as an Honorary Member in 2014. He is a Fellow of the American Ornithologists’ Union and of the American Association for the Advancement of Science. He received the Robert Cushman Murphy Award for Distinguished Lifetime Research from the Waterbird Society in 2006. He studied Common and Roseate terns at Bird Island and other breeding sites in Massachusetts from 1970 until 2010 and has published more than 100 papers on terns in scientific journals.

Carolyn Mostello is a Coastal Waterbird Biologist with the Massachusetts Division of Fisheries & Wildlife. She has studied Common and Roseate terns since 1998, and has directed the program to monitor and conserve them at their breeding sites in Buzzards Bay since 2001.

The authors are members of the Recovery Team for the Northeast population of the Roseate Tern.

Funding for this study was provided by the Blake Fund of the Nuttall Ornithological Club (purchase of geolocators for Common Terns), the U.S. Fish and Wildlife Service (purchase of geolocators for Roseate Terns), and the New Bedford Harbor Trustee Council (support of field operations). We thank Chris Rimmer for his helpful comments on an earlier draft of this article.

Respecting Birds, People, and History at Mount Auburn Cemetery

Sat, 01 Aug 2015 00:00:00 GMT

In 1990, the Cemetery embarked on its first comprehensive planning process, resulting in 1993’s Master Plan. The horticultural directives that emerged from the Master Plan were to: maintain the then-current high level of plant species diversity; continue to plant trees and shrubs that support desirable wildlife populations; increase the amount of brushy, shrub undergrowth to diversify the canopy height and attract a greater variety of birds; maintain some less manicured areas consistent with Cemetery operations to allow for the natural senescence of woody plant material and serve as shelter for wildlife; maintain areas along pond edges for shrubs and small trees to serve as perching and feeding sites for birds; maintain areas of cover and open areas with emergent and other aquatic vegetation by ponds; and maintain the health of the vernal pool in Consecration Dell and the water quality of all other water bodies. These directives have grown in scope and emphasis in the Cemetery’s subsequent yearly planning and budgeting, particularly as we have recognized our importance as a unique oasis for migrating birds and a sanctuary for winter residents and summer breeding populations.

Much of Mount Auburn’s recent work on habitat enhancement has been made possible by funding from the Anthony J. & Mildred D. Ruggiero Memorial Trust established in 1994 to support wildlife habitat and educational programs at Mount Auburn. Through the generous support of the Trust (which funds 75% of a project) and the matching support of other foundations and individuals, Mount Auburn has been able to implement a number of major habitat enhancement projects. In December 2013, the Ruggiero Trust awarded the Friends of Mount Auburn Cemetery a grant of $92,000 to support the creation of a Wildlife Action Plan. With this funding, Mount Auburn brought together a “dream team” of ten professionals—landscape architects, environmental engineers, hydrologists, ecologists, ornithologists, and herpetologists— for a three-day workshop in June 2014. Represented organizations included the Massachusetts Audubon Society, Grassroots Wildlife Conservation, Halvorson Design Partnership, New England Environmental, Patrick Cullina Horticultural Design & Consulting, and Larry Weaner Landscape Associates, as well as independent experts. Each day included tours of different sites, group discussions, and one-on-one sessions. The range of discussion topics included the needs of specific types of wildlife for specific types of habitat, the impact of climate change on bird migration and habitats, the management of water quality in the ponds, and the aesthetic challenge of successful placement of naturalistic landscapes amid more formally designed ones in an active cemetery. The results of this workshop have generated a Wildlife Action Plan, in progress now, to guide our future efforts.

What follows below is a selection of areas where habitat management work has already been conducted and will be continued in the future. Each of these areas is important to one or more of Mount Auburn’s bird communities, from breeding species to spring migrants to fall migrants to winter residents to aquatic birds, and represents a variety of habitat resource types. Many birders are undoubtedly familiar with these areas, but may not be aware of their history. We also hope that as work proceeds under the Wildlife Action Plan, this article will help explain some of what birders might see on the grounds in the future. Every effort will be made to minimize impacts on birds and other wildlife, but some disruption may be inevitable for human visitors.

Auburn Lake

In 1998, Auburn Lake (also known as Spectacle Pond by many) was the first of Mount Auburn’s three ponds to be dredged to improve its health and habitat value, as well as its aesthetics. Over the decades since the creation of the pond in the 1850s, organic matter and sediment had accumulated to the point where Auburn Lake was only about two feet deep in its center and appeared to be largely mudflats during summer drought periods. Working with the direction and support of the Watertown Conservation Commission, the water was drained through a carefully designed filtration system into the Charles River, and a backhoe with a 70-foot reach was used to remove several feet of sediment. A number of shallow emergent zones were left along the pond’s perimeter and planted with wetland species such as bulrushes, sweet flag, and pickerelweed, to provide habitat for a broader diversity of wildlife. In addition, five large Norway maple trees were removed from the steep slope around the north basin and a new understory of native shrubs and groundcovers was planted. A mated pair of Wood Ducks took up residence in Auburn Lake during the first spring after dredging and planting, and since then Green Herons, Great Blue Herons, and many other species of birds, turtles, and amphibians have enjoyed the improved habitat over the years.

Although conditions are vastly improved at Auburn Lake, they can be made better. The northern end of the lake, near the Gardner Mausoleum, is lacking in aquatic vegetation. Mount Auburn plans to install a biofiltration aquatic plant shelf, which will provide the three benefits of filtering storm water before it enters Auburn Lake, adding habitat biodiversity, and improving the aesthetic appearance of the area. During the course of the Wildlife Action Plan charrette, the bird specialists on the team observed that Mount Auburn currently does not include any running water features. Birds, especially migrants, are attracted to the sound of running water, so a running water feature would be of great benefit to birds and the birders who could rely on finding birds there. The steep slope and natural storm water drainage patterns at the northern end of Auburn Lake create an ideal location for the development of a constructed mountain stream. A recirculating pump will ensure consistent flow, and a pedestrian bridge in the current roadway will provide excellent observation opportunities.

Consecration Dell

Planting of native species after removal of non-native species around a hillside tomb on the western slope of Consecration Dell, 1998.

Consecration Dell, same hillside tomb as previous photo, 2011.

Unlike the rest of the Cemetery, where intensive horticultural management has maintained the landscape over the decades, the 4.2 acres of Consecration Dell’s natural valley had been minimally managed from the 1890s until 1997. During this time, invasive Norway maple had become co-dominant with the native red oak in the forest canopy. In woodlands where these maples become established, there is a conspicuous absence of understory vegetation. This condition further complicated matters in the Dell, where the steepness of its slopes had led to severe soil erosion problems. Work to restore the Dell to a more natural state began in 1997 with the planting of native species along the banks of the pool. The Dell was—and is—ecologically significant in part because of its resident population of spotted salamanders, one of the few in eastern Massachusetts. Our goal was to enhance the area aesthetically while also respecting the habitat requirements of the salamanders, which breed each spring in the vernal pool. The spotted salamander population has been carefully monitored each year, and it has been gratifying to note its overall success.

Since 1997, we have gradually expanded our woodland restoration efforts onto the slopes surrounding the pool, planting native New England species of trees, shrubs, ferns, and other groundcovers. With each phase of the woodland restoration, the first step has been to remove the Norway maples and other non-native species, such as Japanese yews and Japanese barberries, and replace them with native species ranging from sassafras and striped maple to mountain laurel, Christmas fern, and Solomon’s seal. In 2003, several hundred seedlings of Norway maple, along with a number of mature trees, were removed from the southern slopes of the Dell. Over 400 new trees and shrubs were installed on the slopes where the invasive trees were removed, and more than 3,400 herbaceous plantings created carpets of ferns and woodland wildflowers, which are lush and vibrant today. As all of these plantings have matured, including many that provide nuts, seeds and fruits that are attractive to a wide variety of birds and to the insects that birds feed upon, the rebuilt understory vegetation has provided shelter and nesting materials. Visitors also may have noticed that unlike most other areas of the Cemetery, deadwood, whether standing or fallen, is allowed to remain in place as much as possible to provide additional food and shelter resources. Not only is this important for a wide variety of birds and invertebrates, but this practice is also aesthetically harmonious with the naturalistic woodland character of the Dell.

Our overall objective has been to make Consecration Dell a better natural habitat for birds and an ecologically sound plant community that will be sustainable long into the future, and we feel secure that we have made great strides toward reaching that goal. Future work will include additional plantings on the highest slopes of the Dell, to stabilize the soil in that area and to extend the prime habitat further upslope. In the course of this work we will improve the condition of the rustic walking paths that traverse the steep slopes. This will be a welcome improvement for some visitors who have avoided the paths out of safety concerns for exposed roots and washed out paving material.

Halcyon lake

Aquatic plants being installed at Willow Pond’s emergent shelf, 2005.

Emergent shelf at Willow Pond, 2015.

Throughout most of the Cemetery’s history, the area around Halcyon Lake had an open, formal character, which included large expanses of turf running to the water’s edge. In spring of 1999, several large native trees (oaks and tupelos) and small ornamentals (dogwoods and crab apples) were planted around the lake. The invasive yellow iris along the entire lake edge was taken out, and hydraulic dredging to clear out decades of muck was done in summer 1999. Since then, a filtration system has kept algae and scum at bay, and plantings along the eastern edge of the lake have matured into an aquatic shelf providing useful habitat for birds and amphibians. However there is a lot of room for improvement, and future plans include more intensive invasive species control, replanting of the aquatic shelf, a new biofiltration system to further improve water quality, and, potentially, the addition of a floating island which would add places to hide for small fish and amphibians as well as safe resting sites for turtles and water birds.

Narcissus Path and Beech Avenue Wildlife Corridor

In an effort to provide continuity between habitat zones, the Narcissus Path and Beech Avenue wildlife corridor was the first step in knitting together a series of wildlife refuges that have historically been somewhat segregated. Its southern end lies only 350 feet from the entrance to Consecration Dell. At its northern end lies Indian Ridge, a long (one third of a mile) stretch of semi-wild landscape that also has been targeted for habitat replanting in the future. In the angle between these two ridges lies Auburn Lake, with its nearly five-acre basin of diverse wildlife habitat. More than 3,900 plants, including several new varieties of hollies, were installed in an area covering about one acre. The plant list was chosen with the primary objective of offering food resources and protective cover to birds, butterflies and other insects, and many small animals. This project was completed in 2013, with ongoing maintenance.

Wildflower Meadow at Washington Tower

The wildflower meadow at Washington Tower represents a plant community that has become scarce in Massachusetts due to development, fragmentation of farmland, pollution, and competition from invasive plants. Created in 2007 with the installation of almost 10,000 grasses, herbaceous perennials, and shrubs, the meadow benefits many species of butterflies, insects, and small mammals and also contains a seep, a small water feature that is attractive to these animals. Although it is not a large enough habitat to benefit grassland birds, it offers food sources to many other species, including hummingbirds. The wildflower meadow has been quite successful and will need only refinements of the plant species present and some renovation of the seep into a more attractive feature.

Willow Pond

In 2004-2005, the Cemetery completed the installation of a butterfly garden and a wetland emergent zone habitat at Willow Pond. A hydro-rake was used to remove invasive aquatic weeds and accumulated organic debris from the bottom of the pond. A shallow underwater shelf with aquatic plantings was then constructed to provide wildlife habitat and also to act as a biofiltration system at the point where significant water and sediment flow into the pond during major rain events. As at Halcyon Lake and Auburn Lake, these efforts did result in increased habitat for birds, fish, amphibians and invertebrates, but some significant types of habitat were absent throughout most of the pond, particularly cover for tadpoles and frogs. An added complication came in the fall of 2014, when heavy rains caused flooding in our storm water drainage system that washed away much of Willow Pond’s biofiltration system. Visitors may have noticed that the traditional turtle basking area at the north end of the pond has vanished, a casualty of the flooding. We will take advantage of this opportunity to rebuild a more extensive aquatic shelf with a viewing platform for visitors, and will also investigate adding floating islands to the main body of the pond. In addition to adding habitat resources, the vegetation on floating islands helps improve water quality as the root system filters nutrients out of the water.

These areas represent the major, highly visible projects at Mount Auburn over the past couple of decades, but there have been and will continue to be other, less immediately obvious habitat enhancement projects throughout the Cemetery. One substantial challenge we face is that one of the most valuable habitats for the breeding bird populations of Massachusetts is shrubland, characterized by multiple dense layers of woody vegetation from ground level to up to twenty feet high. Shrublands are by their nature ephemeral, typically occurring as transitional or early successional habitat following some disturbance to an area and preceding the establishment of woodland, and the general populace sees them as unkempt or unmanaged landscapes. While we are able to maintain some areas of the Cemetery in a naturalistic state, such as Consecration Dell, we have a responsibility to our clients and their families and to our mission of preservation of the historic landscape that constrains us from letting nature take its course throughout the grounds. However, we are exploring the possibility of creating managed shrublands with a mix of flowering and fruiting plant species that would mimic the structure of a shrubland, even if it does not mirror the typical species found in a natural Massachusetts shrubland.

Other future areas for improvement include Alice’s Fountain, a small water feature constructed in the 1860s in an area that had been wet bog and is now a naturalistic pool with a drip fountain feature. The pool could be expanded into a larger vernal pool for additional salamander habitat and provide an important connector between Consecration Dell and Willow Pond, while also helping with our storm water management. And we will also be watching climate change closely, adjusting our plant species selections throughout the Cemetery in order to ensure that there will be food availability for long-distance migrants when they arrive in profound need of sustenance.

Mount Auburn has a long and illustrious history in the birding community, and we are looking forward to continuing that relationship in our collaboration with Mass Audubon now and in future Citizen Science projects that will help collect and disseminate data on the abundance and distribution of birds throughout the year. Please stop by the Visitors Center or check our website (www.mountauburn.org) regularly for updates on all of these projects as well as our future initiatives.

Dave Barnett is President & CEO of Mount Auburn Cemetery, and Regina Harrison is Executive Assistant at Mount Auburn Cemetery and an Associate Editor of Bird Observer.