February 2018

Birding Minute Man National Historical Park

Wed, 31 Jan 2018 00:00:00 GMT

American Woodcocks are regulars in April. All photographs, unless otherwise indicated, by Jay Dia.

Route #1 Meriam's Corner Route

Basics: 1.7 miles round trip, easy terrain
Best: All year
NOTE: This route may be icy in winter

The Meriam's Corner route (Figure 2) is by far the best-known by birders. It travels though several different habitats and offers wonderful opportunities for encountering a rarity. The historical tour signposts along the trail make convenient (and fun) markers for my birding descriptions, so I will make use of them.

Figure 2. Meriam's Corner Route.

Before you leave the lot, look across Lexington Road to the old Palumbo Farm, recently acquired by Minute Man as the result of a 1968 agreement with the Palumbo family. This area hosts various ducks, swallows, and sparrows. Northern Harrier is a regular visitor and Red-tailed Hawks nest here, their giant young squawking from utility poles in the spring. For details on birding this area, see the "Other Birding Spots in the Park" section below.

From the Meriam's Corner lot you will find the wide trail on the lot's east side beginning at a short bridge. As you walk this circuitous route through varied terrain, pause to imagine the string of battles between the outnumbered British regulars and the colonial militia that took place along this Battle Road on April 19, 1775, and began here in Meriam's Corner. At the time most of this area was cleared for agriculture, and the colonists sought to "…attack and annoy the enemy from behind trees, rocks, fences and buildings, as seemed most convenient…" (Ripley 1832, p. 22-3).

Pre-dawn near the lot, the calls of Great Horned Owls can often be heard from several directions. From late March to mid-April the fields surrounding the lot are a sure bet for finding American Woodcocks. They will begin to peent about 20 minutes after sunset, and their courtship display flight can be heard and sometimes seen without going more than a few steps from your car. For cushy birding bring a lawn chair and a (non-alcoholic) drink.

As you begin down the trail, check the bushes on your left for warblers on migration and sparrows year round. Before the snow is deep White-throated Sparrows dig in the leaf litter in brushy areas all along this trail, and Fox Sparrow is a possibility among them. The fields on the right and ahead often hold Savannah Sparrows in spring.

At Signpost #2 (350 feet from lot) there is a small wetland on your left. Yellow Warbler and Willow Flycatcher nest here. Kingfishers can often be seen flying toward Elm Brook, and Green Herons are often seen in summer. Check for blackbirds in the dead trees, including occasional Rusty Blackbirds in late fall.

From here the trail continues between fields on the left and wooded edges on the right toward Signpost #3 (0.1 miles from lot). In summer the wooded edges are busy with feeding young of common species, and in winter with feeding flocks that often include Golden-crowned Kinglets.

A short distance ahead you will be in woods on both sides of the trail. American Crows have nested in this section of woods each of the last two years, and their loud family vocalizations before and after the young fledge are hard to miss.

Near Signpost # 4 (0.3 miles from lot) you will emerge into a fence-lined grassy area. At the woods' edge the bee-buzz of Blue-winged Warblers can be heard in spring. Bluewings nest in these brushy areas, especially spots that are slightly wet, throughout the park. Watch the tall trees on your left for warblers and gnatcatchers, and less commonly Orchard Orioles and Indigo Buntings in spring. Check the bittersweet vines on your right for feeding warblers even into early winter. I have seen Lincoln Sparrow on the fence line here in fall. Red-tailed Hawks and accipiters frequent the area. Last year in this area I watched a Sharp-shinned Hawk attack a surprised Hairy Woodpecker, which managed to get away pik!-ing indignantly for minutes afterward. Note that Signpost #5 is missing.

Just after a short wooden culvert bridge you will come to large open agricultural fields on your right and left. This is one of the best areas in the park for birding, and in particular for rarity hunting. In the evening in early April Wilson's Snipe roost in the plowed field edges and can often be seen in large numbers camouflaged in the plow ruts if one takes the time to look carefully. Flooded fields can bring sandpipers, including Pectoral, Spotted, and Solitary. During fall migration I have seen as many as 50 Yellow-rumped Warblers feeding on the low plants in the field on the right. Rarities, including Orange-Crowned Warbler, Lark Sparrow, Vesper Sparrow, and Dickcissel, have all been reported here.

At Signpost #6 (0.5 miles from lot) the trail takes a 90-degree right turn. If you continue straight instead of taking the turn you will shortly be on Kaveski Farm Conservation Land. Note that this trail may be muddy and involves a wet crossing. Hands down one of the best birding spots in the area, this detour is always worth your time. The fields adjoining Minute Man NHP and Kaveski Farm can hold many surprises. Raptors, including Cooper's and Sharp-shinned hawk, and less commonly American Kestrel, Merlin, Peregrine Falcon, and Red-shouldered Hawk, are all regulars here, particularly in fall.

Back on the trail, after you turn the corner you will have a grassy field on your left, which hosts bluebirds and finches year-round and the occasional Eastern Meadowlark in spring. On your right, check the agricultural fields in fall and spring for Killdeer and look for American Pipits and flocks of Horned Larks in fall and winter. Glossy Ibis were brief but welcome visitors in April of 2015 and 2017.

Ahead is the present-day Carty Farm and site of the historic Olive Stow Farm. Here in 1775 the 48-year-old widow Stow lived and managed the farm with her two teenage children — no easy feat for a woman of her time. Look in the trees near the brushy edges and farm for Indigo Bunting and Eastern Phoebe. In late spring this is the spot for perhaps the most predictable Alder Flycatcher in Concord. I have seen it in these trees and heard it in the brushy area as well. Alders are present late May through early June at several locations in the park, and I am hopeful that they are breeding here but as yet do not have direct evidence. Keep in mind that audio confirmation is generally needed for Alder identification as Willow is found in the park as well.

Continue onto the boardwalk checking the low bushes as well as the trees beyond the boardwalk for warblers and flycatchers in spring and fall. When you reach the stone mile marker near the road you have reached the end of this route. From here you can retrace your steps to return to the lot. For a longer outing you can loop back through Kaveski Farm Conservation Land. To do so, turn left at the green farm stand onto Shadyside Lane, and continue approximately 0.5 miles to the Kaveski Farm entrance. The main trail through Kaveski Farm will take you back to Minute Man. Alternately, you can cross Shadyside Lane and continue along the sidewalk to Route #2 below.

Route #2 Brooks Farm Boardwalk Route

Basics: 1.5 miles round trip, easy
Best: Spring, summer; sections in winter

The Brooks Farm Boardwalk route (Figure 3) is a pretty trail through various habitats, particularly great for an evening birding outing and worth braving the runners and cyclists you will encounter. I have not birded this route much in fall, so you may have unexpected surprises, particularly near the stream at the end of the boardwalk. Species listed are present spring or summer unless otherwise noted.

Figure 3. Brooks Farm Boardwalk Route.

This route begins in the Brooks Farm lot on Route 2A in Lincoln just east of its intersection with Lexington Road. In 1775 this area included multiple homes belonging to the Brooks in a sort of family village with businesses, including a tannery, slaughterhouse, brick kiln, and later a tavern complete with a ballroom on the second floor.

Take a moment before leaving the lot to look across the street to the pasture where the impressive-looking Highland Cross and Randall Lineback cattle graze. Look for swallows in season, and Wild Turkeys and various hawks all year. Bluebirds and finches fly among the trees and historic ruins in the open areas near the lot, and there is often a Mockingbird singing from the lamppost or bushes of the historic Job Brooks house. Sapsucker is possible here in winter.

From the lot take the main trail to the T intersection. Take a left for a 150-foot quick detour to check the dead trees for Pileated and other woodpeckers. Returning to the intersection, continue on straight, checking the brush on your left for the many nesting catbirds, as well as American Redstarts, which occasionally nest here.

Elm Brook Boardwalk. Photograph by Minute Man National Historical Park.

As you head into the marsh and onto the boardwalk (0.3 miles from lot) look for waxwings, orioles, grosbeaks, Yellow Warblers, and Common Yellowthroats. Check the bare tree tops and listen for woodpeckers and hawks in all seasons and for flycatchers in late spring and early summer. Alder Flycatcher is a regular at this location in the evening in late May and early June, and in May 2016 my husband and I observed an Olive-sided Flycatcher here. In early summer watch for feeding Common Nighthawks.

The stream at the end of the boardwalk attracts birds coming in for a drink. Here the trail takes a left into a wooded habitat where various woodpeckers nest. Just after entering the woods you will came to a large rock on your left. Stop here and look toward Elm Brook for swallows, blackbirds, and herons. A scope is helpful at this location. In winter this is a good place to observe White-throated Sparrows, Golden-crowned Kinglets, and other songbirds coming in and out of the bushes.

Continue into the woods, looking for Hermit Thrushes scurrying among the fallen logs, and in the evening listening for the sounds of the Wood Thrush. Ascending a gentle slope you will come to a low stone wall. Keep in mind that any area where you see a stone wall was likely cleared of vegetation for agriculture at one time.

As you emerge from the woods you will be in the historic Bloody Angle (0.6 miles from lot). Here on April 19, 1775, British regulars were fired on from all directions in a battle in which 30 regulars and four colonial militia men were killed. Perhaps with poetic justice, the Bloody Angle teems with new life each spring and summer. Around 7:00 pm on early June evenings male Indigo Buntings begin advertising from very visible perches in the trees of the open area. Their numbers have decreased over the past five years, but I am hopeful that this is not a permanent trend. As in all of the brushy edges of the park, especially slightly wet edges, listen for nesting Blue-winged Warblers. Other nesting species here include Eastern Wood-Pewee, Great Crested Flycatcher, Rose-breasted Grosbeak, and omnipresent Chipping Sparrow. Turkeys roost for the night in the tall trees of the wooded edges, their awkwardly oversized young balancing on narrow branches.

In mid-July to early August the low bushes and vines that edge the Bloody Angle are alive with feeding bird families. Stand for a spell and see what emerges: orioles, tanagers, gnatcatchers, grosbeaks, buntings, and occasional warblers. Watch for Ruby-throated Hummingbirds feeding on the trumpet vines that wind up the trees where the trail bends sharply right.

Shortly you will come to another T intersection. Turn right onto Battle Road, and continue to the grave of unnamed British soldiers. Looking down the left path you will see a stone marker on the right indicating the end of the Vernal Pool Trail. If time allows, take a detour down part or all of this wonderful trail (described in Route #3 description, but keep in mind you will be approaching it in reverse). If not, continue straight ahead with the wooden fence line on your right. Here you will have the edge of the Vernal Pool area on your left where Scarlet Tanager, Northern Waterthrush, and various thrushes, including Veery are dependably heard.

Retrace your steps to return to the lot. As you pass the edge of the Bloody Angle and begin to enter the woods, look over the hillside. This is Brooks Hill, which colonists climbed to lie in wait for the British. On a peaceful day this view can bring a great appreciation for the natural beauty here and a reverence for the pivotal events that took place where you now stand.

Route #3: Hartwell/Vernal Pool Loop

Basics: 1.2 miles: Vernal Pool Trail is uneven muddy terrain, other portions are easy. Insect repellant is suggested.
Best: Spring, early summer; sections in fall and winter

The Hartwell/Vernal Pool loop (Figure 4) is an under-appreciated birding hot spot that is rich with migrants in spring and some wonderful nesting species in summer. In fall the brushy trail behind the tavern is worth a look. In winter, check the cone trees at the start of the Vernal Pool Trail and open areas and tall trees lining Battle Road and surrounding the Hartwell Tavern.

Figure 4. Hartwell/Vernal Pool Loop.

This loop begins at the Hartwell Tavern lot on Route 2A in Lincoln, just west of Hanscom Drive. Don't rush to leave the lot as some of your best sightings may be here. In spring warblers, often including Blackburnian, and vireos abound in the treed lot.

From the lot head down the wide main trail, named Bedford Lane. A stop at the restrooms on your left is worthwhile first for the obvious reason—it's among the nicer of birding bathrooms—and second, and more importantly, because Scarlet Tanagers and Baltimore Orioles often nest nearby in June. Look for the intricate sac-like oriole nests in the open treed areas and tanager nests in the more densely wooded areas. Listen for Prairie Warblers singing near the road in late May.

As you continue on the wide main trail check the bushes on the right for migrants and residents. This is where, on an eight-flycatcher-species day at the park in late spring, I observed both Yellow-bellied and Olive-sided flycatchers. In early spring Veeries may be seen hopping on and along the low rock walls ahead.

Vernal Pool Trail.

About 350 feet down the main trail you will find a sign for the entrance to the Vernal Pool Trail on your left. You will often have this quiet trail to yourself as you bird. Before entering the woods, the trail moves through a transitional habitat where you can find many migrating warblers in spring and nesting species in summer, including Rose-breasted Grosbeak, American Redstart, Blue-winged Warbler, and Blue-gray Gnatcatcher. There are tall conifers in this open area that attract feeding birds to their cones in winter and are worth a look in irruption years for winter specialties.

Entering the woods and wetland habitat, look and listen for thrushes in spring and summer: Swainson's and Hermit on migration, and Wood and Veery nesting. Northern Waterthrush, Ovenbird, Scarlet Tanager, and Pileated Woodpecker are all nesting species here, and Brown Creepers can be heard year-round. At the T intersection (0.4 miles from lot) ignore the sign with the left-pointing arrow, and turn right to follow the boardwalk, watching carefully in the low wet areas for camouflaged ground-feeders.

On emerging from the woods you will be on Battle Road (0.5 miles from lot). A left turn takes you to the Bloody Angle described in Route #2 above. I recommend taking a 20-minute or so detour to this historic and very birdy area, then returning to Battle Road.

Returning to the Vernal Pool Trail's end where you emerged, continue on Battle Road. This will be a right turn if you skipped the Bloody Angle detour. In spring check the tall trees bordering the trail for warblers and nesting gnatcatchers. In winter feeding flocks are active in the branches.

Continuing on, you will pass grassland areas with small trees on your left where in June you can see numerous Baltimore Oriole nests and Wild Turkeys wading through the grass with their young. In winter check the tall trees around the tavern for bluebirds, waxwings, and a possible sapsucker. In 2017 a pair of Yellow-billed Cuckoos stayed in the wooded area opposite the tavern all summer, and although I could not locate their nest, their continuous presence from late May to late June makes breeding likely.

Shortly you will arrive at Hartwell Tavern (0.7 mile from lot) on the left. Here Ephraim and Elizabeth Hartwell ran part of their home as an inn. If the Tavern is open you can take a non-birding pause to tour the beautifully restored interior, join a ranger-led walk, or perhaps watch a musket shooting demonstration.

Walk behind the tavern's right side to the wooden fence line (0.8 mile from lot). You will find that there is a rough trail that follows the fence line on the opposite side from the tavern. During spring migration there are always many warblers, kinglets, and vireos along this short trail, often including Tennessee. Accipiters hunt here in all seasons. You can exit this trail by retracing your steps to Hartwell Tavern or, if the trail is passable, continue on to the Smith House sign (0.9 mile from lot) and turn right. This will take you back to Battle Road. Turn right here to return to the tavern. Do be sure to check for ticks upon your return to the tavern and please respect private properties below the trail. Head back to the lot on Bedford Lane opposite the tavern.

Blue-winged Warblers nest throughout the NHP.

Other Birding Spots in the Park (East To West)

Fiske Hill is accessed from the eastern-most lot in the park on Old Massachusetts Avenue just off Route 2A in Lexington. It is a lovely walk to the top of the hill. Invasive plant removal is planned for this area, and the rock outcrop's open grassy top may turn out to be a new hot spot for nesting species… stay tuned.

Battle Road Visitor Center on Route 2A has a small pond that hosts various species, particularly in the colder months when the pond remains unfrozen for a while. Check the low, wet, brushy areas along the side of the lot for interesting sparrows any time of year.

Dirt Road Fen is a small but special wetland down a dirt road across Lexington Road from the Meriam's Corner area. This is a unique habitat, attracting migrants in the spring, and some special nesting species, including Ovenbird, Veery, and Northern Waterthrush. Note that although the wetland is Minute Man NHP property, the road itself is private. The owners are gracious to birders, but please be respectful by stopping at the National Park Service boundary sign. An artist friend of the owner has created found-art sculpture all along the road. Please use caution on Lexington Road.

Palumbo Farm Conservation Land is a grassland across Lexington Road from Meriam's Corner. Park officials do not mind if birders walk along the old road edging this field; enter where you see the chain and "No public access" sign. However, the park asks that birders please stay clear of the old farm buildings. This area hosts various swallows, ducks, flocks of turkeys, and raptors including Northern Harrier. Skirting the buildings as best you can, check the back corners of the field for sparrows. Please use caution on Lexington Road.

The Old North Bridge is a historical must if you have never visited the Minute Man NHP. While you are brushing up on your Revolutionary War history, check the lot across the street and the brushy river edges for migrants. The tall oaks along the path host bluebirds, orioles, woodpeckers, and gnatcatchers in spring and possible sapsuckers in winter.

Future Conservation Efforts and eBird Data

On a closing note, I have been enthused by how interested park officials have been in survey findings, eBird data, and in protecting wildlife and their habitats within the park. Over the next couple years I will be working with the park on creating a printed and PDF bird checklist for park visitors, adding some bird walks to the park's wonderful variety of public programs, and compiling some suggestions for simple bird conservation strategies. Your eBird submissions will be helpful in these efforts. If you have personal eBird locations within the park, consider merging them to one of the two eBird hotspots with the park so that your data will be included in these efforts.

Meriam's Corner: http://ebird.org/ebird/hotspot/L858741

Minute Man National Historical Park: http://ebird.org/ebird/hotspot/L941919

I hope that you will enjoy birding at Minute Man NHP and I look forward to hearing what you find!

Acknowledgements

Many thanks to Margie Coffin Brown, director of Cultural and Natural Resources at Minute Man NHP for her time and interest, and for the use of park photos and historical materials. Thanks to Cherrie Corey and David Swain for editing assistance; to Jason Forbes for edits and lending his own inside knowledge of the park; and to all of the birders who have contributed eBird data used for this article. Lastly thanks to my husband Jay for assistance with mapping apps and GPS, walking companionship, and patience.

Resources

Dietrich-Smith, D. and Olmsted Center for Landscape Preservation 2005. Cultural Landscape Report for the Battle Road Unit, Minute Man National Historical Park, Vol. 1. Brookline, Massachusetts: National Park Service Olmsted Center for Landscape Preservation.
Minute Man National Historic Park website: www.nps.gov/MIMA
Ripley, E., with other citizens of Concord. 1832. A History of the Fight at Concord on 19th of April 1775. Concord, Massachusetts: H. Atwill.
Ryan, D. Michael. 2005. Noah Brooks Tavern at http://lincolnminutemen.org/history/articles/ryan_brooks_tavern.html
Yocum, B. A. 2004. Meriam House Minute Man National Historical Park, Concord, Massachusetts Historic Structure Report. Lowell, Massachusetts: National Park Service.

Kathy Stark Dia is a former professional ballet dancer who now teaches ballet in Acton, Massachusetts. She grew up in Pittsburgh in a family who enjoyed nature but came to birdwatching later in life. After leaving a full-time position at an arts high school, she began working part-time for Mass Audubon Broadmoor, where she leads school field trips and adult bird walks. Kathy volunteers for Minute Man NHP, Vermont Center for Ecostudies, Brookline Bird Club, and at Great Meadows National Wildlife Refuge.

Red Crossbills in Massachusetts and the Northeast: A Possible Irruption in 2017–2018

Wed, 31 Jan 2018 00:00:00 GMT

Early work by Groth (1993) and continuing research by others (Benkman 1993, 2009; Benkman et al. 2009; Parchman and Benkman 2009) initially resulted in the identification of 11 distinct Red Crossbill call types in North and Central America. Now that Type 9 has been elevated to species status as the Cassia Crossbill (Loxia sinesciurus) (Chesser et al. 2017), 10 call types remain. Although difficult to impossible to differentiate visually, each type can be reliably identified from recordings of its flight call—the emphatic jip-jip-jip calls heard when the birds are flying overhead and occasionally given by perched birds as well—but not by their songs or other vocalizations. When encountering crossbills in the field, one can record the flight calls using the built-in microphone of a smart phone. When embedded into an eBird report, such recordings allow identification to type by others. The report can then be updated to reflect call type. If any additional call types are split off as new species in the future, this split would be updated in one's eBird account. For additional, useful information on recording flight calls as well as comprehensive descriptions of the various call types, their characteristics and habitats, refer to Young and Spahr (2017).

There has been discussion of splitting the remaining 10 flight call types into species, but more work is needed before such a change would be scientifically justified. Red Crossbill speciation and call types are a rich area of research and one where birders can make a significant contribution by recording and reporting flight calls.

Female Red Crossbill extracting seeds in Pitch Pine.

The last major irruption of Red Crossbills into the Northeast occurred in 2012 when western flight call Types 3 and 7 or 10 were seen in large numbers in the eastern states. During this 2012–2013 irruption, there were dozens of crossbills seen in many coastal locations in Massachusetts, Rhode Island, New York, and even as far south as New Jersey and Virginia. The winter of 2017–2018 could deliver an irruption surpassing that of five years ago. In part due to drought conditions followed by a wet spring and summer in the Northeast, this year's cone crop has the potential to be a once-in-a-few-decades event, with native spruces, white, pitch and red pines, hemlock, and tamarack all showing bumper cone crops. In addition, an epic cone crop failure in the Rockies is driving birds out of their normal wintering ranges. As of this writing in December 2017, there are massive numbers of Red Crossbills spreading across the country, including many western flight call types showing up in the plains states, Great Lakes states, and along the Pacific coast from California to Alaska. Crossbills are even frequenting small stands of pines in the lowlands of the desert Southwest.

Natural History

Red Crossbills have evolved a specialized, crossed bill specific to extracting the seeds from conifer cones, and their dependence on the cone crop is the underlying key to their natural history. Irruptions can bring flocks all the way across North America in search of suitably heavy crops. The species is unique in that nesting is closely tied to food availability, not necessarily to season. Crossbills in North America breed primarily in two cycles, one in summer (July through early September) when newly-developed, ripening cone crops are present, and again in winter-spring (January through early May), coinciding with the last of the remaining good cones. No nests or nestlings of Red Crossbills have ever been found in October or November in North America, though they have been found in Europe during these months. There are, however, many North American records of juvenile-plumaged birds in October and November. Matt Young of the Cornell Lab of Ornithology, who has been researching crossbills for 20 years, notes that these autumn observations of Red Crossbills in juvenile plumage may have given rise to the notion that North American crossbills can nest at any time of the year.

Female drinking; had been picking up gravel from road.

The female incubates a clutch of typically three eggs, with the male bringing food for the female and later for the hatched chicks. Both parents bring food to the chicks beginning four or five days after hatching, feeding them regurgitated seeds. The young fledge after 18 to 22 days, but it takes a bit longer for their bills to develop sufficiently to extract cone seeds, so there is a short period when the fledged birds are dependent on their parents. In addition to cone seeds, food sources include the buds of deciduous trees, berries, and insects. Crossbills can also be seen on dirt roads picking up gravel and salt. Gravel grit aids in digesting vegetable material, and the ingestion of salt may be related to a calcium deficiency in their diet (Tozer 1994).

Birds that hatch in summer molt in late summer or fall, coinciding with the fall molt of adult birds. However, it's not uncommon to see birds in a suspended molt for several months. Birds that hatch in late winter or spring molt about three months after hatching, and then again during the fall molt period. Juvenile plumages are thus seen over an extended time period.

Red Crossbill Speciation

It is unusual that a single avian species should have so many distinct, differentiable population types. Research by Parchman and Benkman (2002) and others suggests an explanation. Cone crops and crossbill populations seem to be engaged in an "evolutionary arms race" that has led to the creation of specialized bill types, particularly in the western United States where isolated ranges of lodgepole pine create biogeographical islands in which crossbills and cones have co-evolved, and continue to do so (Benkman, 2009). This dynamic led to the evolution of the Cassia Crossbill. Rocky Mountain lodgepole pines (Pinus contorta latifolia) in the "islands" of southern Idaho—where Cassia Crossbills are found—developed larger, thicker-scaled cones than in nearby ranges. This potential food source, in turn, favored the development of larger-billed crossbills and the evolution of the newly recognized species. That this phenomenon may be ongoing elsewhere is a particularly interesting focus of researchers, giving us a chance to observe natural selection in action before our very eyes!

Male feeding on deciduous buds.

Recent Red Crossbill history in Massachusetts

In the winter and spring of 2016–2017, there were small concentrations of Red Crossbills in Massachusetts reported from two regions, Salisbury Beach and Plum Island in the east and the Montague Sand Plains in central Massachusetts. Of the many reports to eBird from the former area, only one recording was reported, for the small- to medium-billed Sitka spruce crossbill—Type 10 or possibly Type 7. The primary range for call Type 10 is the coastal Pacific Northwest, from Northern California into central Oregon; Type 7 possibly is endemic from central to northeastern Canada. In the Montague Sand Plains, the Sitka spruce type was recorded along with the large-billed ponderosa pine crossbill, Type 2. Type 2 crossbills are most common in the ponderosa pine forests of the West, but can be found continent-wide in stands of hard-coned pines, including red and pitch pines of the Northeast.

The last reported summer sightings were on June 4 in the Sand Plains and July 31 in the Salisbury and Plum Island region. Breeding in Massachusetts was certainly possible, and even suggested, but unfortunately not documented. Elsewhere in the Northeast, crossbills were noted and confirmed as breeding in New York, New Hampshire, and Maine, as well as in southern Ontario and Quebec in Canada. In addition to Type 10, Appalachian or Type 1 birds were confirmed breeding near Type 10s in New Hampshire and New York.

Where to Look in Massachusetts and the Northeast

The 2017–2018 invasion is well underway. Western flight call Types 2, 3, 4, and even 5 were moving east as early as July and August. By November, the irruption in the plains states was widespread, with birds common in Texas northward through the Dakotas, and eastward into Missouri, Indiana, Ohio, Michigan, Wisconsin, and Minnesota. In the Northeast, a few Type 1, 3, and 10 birds have been recorded in New Hampshire and Maine recently, with some Type 10 and untyped birds trickling into Massachusetts and Vermont beginning in late November. Given the failure of the cone crop in the West, and the general dearth of cone-producing trees in the plains and Midwest, it is inevitable that crossbills will continue to arrive in the Northeast. Will they make it south, or stay north where the cone crop seems to be good as well? The abundance of cones throughout the Northeast and north into Canada may result in a wide dispersion of birds, making them harder to locate.

In Massachusetts the cone crop is good in most locations, and crossbills may appear anywhere with cones. Historically good locations have been Salisbury Beach State Reservation and the Plum Island area. Miles Standish State Forest and Cape Cod also have substantial pine forests and can hold birds. Inland and west, any substantial grove of Norway spruce, hemlocks, or cone-laden pines, such as the pitch pines in the Montague Sand Plains, could hold crossbills. Other areas likely to host birds include coniferous forests in Savoy and Windsor, and the October Mountain State Forest northeast of Lee. These areas in central and western Massachusetts may be bigger players this year because of their large cone crops, but given the nomadic nature of the birds, and their ability to fly long distances, lots of searching may be required to find them. The challenge of finding birds this year—and recording their flight calls—is a great opportunity for citizen science to contribute to the exciting, ongoing research into this interesting species.

References

Benkman, C. W. 1993. Adaptation to single resources and evolution of crossbill (Loxia) diversity. Ecological Monographs 63: 305–325.
Benkman, C. W. 2009. Diversifying Coevolution between Crossbills and Conifers. Evolution: Education and Outreach. 3: 47–53.
Benkman, C. W., J. W. Smith, P. C. Keenan, T. L. Parchman, and L. Santisteban. 2009. A new species of Red Crossbill (Fringillidae: Loxia) from Idaho. Condor 111: 169–176.
Chesser, R.T., K. J. Burns, C. Cicero, J. L. Dunn, A. W. Kratter, I. J. Lovette, P. C. Rasmussen, J. V. Remsen, Jr., J. D. Rising, D. F. Stotz, and K. Winker. 2017. Fifty-eighth supplement to the American Ornithological Society's Check-list of North American Birds. The Auk 134: 751–773.
Groth, J. G. 1993. Evolutionary differentiation in morphology, vocalizations and allozymes among nomadic sibling species in the North American Red Crossbill (Loxia curvirostra) complex. University of California Publications in Zoology 127: 1–143.
Parchman, T. L., and C. W. Benkman. 2002. Diversifying coevolution between crossbills and black spruce on Newfoundland. Evolution 56: 1663–1672.
Tozer, R. 1994. Red Crossbills Feeding at Mineral Sources. Ontario Birds 12: 102–108. Accessed December 6, 2017 at: https://sora.unm.edu/sites/default/files/102-108OB Vol12%233 Dec1994.pdf
Young, M., and T. Spahr. 2017. Crossbills of North America: Species and Red Crossbill Call Types. eBird 11 October, 2017. Available online at: http://ebird.org/content/ebird/news/crossbills-of-north-america-species-and-red-crossbill-call-types/

Jeremy Coleman is an architect who has recently moved to Shelburne Falls, Massachusetts, from Brattleboro, Vermont. His interests include photography, birding, and exploring the natural landscape.

Tim Spahr runs a scientific consulting company focused on asteroid science. When not working, Tim can be found in and around Worcester County, Massachusetts, chasing warblers and Red Crossbills if they are nearby.

A History of Winter Crow Roosts and a Visit to a Roost in Lawrence, Massachusetts

Wed, 31 Jan 2018 00:00:00 GMT

Communal roosting by large numbers of crows is not well understood. Sibley (2001) offers some explanations:

Some evidence indicates that information about profitable foraging areas may be passed on at roosts; hungry birds follow well-fed ones to better feeding sites the next day. Another explanation is that the birds gather near reliable feeding areas, where they can be sure to get something to eat first thing in the morning and again at the end of the day. Large roosts may also offer protection from predators and the comfort of converging at warm, sheltered spots.

In Massachusetts, maximum numbers of crows are recorded in October and March, and many crows are seen during hawk migrations. High counts include 1,000+ in Berkshire County on October 22, 1950; 1500 in Needham on October 30, 1979; and 1175 in Ashburnham on October 27, 1979. In spring, high counts include 700+ in Dartmouth on March 23, 1958, and 600 flying north at Plum Island, on March 15, 1993 (Veit and Petersen 1993).

Early History of Winter Roosts

The most famous early account of a crow roost was by Alexander Wilson in his American Ornithology (1811). He described a roost that occurred in the late 1700s that

is near New Castle, on an island in the Delaware. It is known by the name of Pea Patch, and is a low, flat, alluvial spot of a few acres, elevated but little above high-water mark and covered with a think growth of reeds....It is entirely destitute of trees, the crows alighting and nestling among the reeds…

The colony was once destroyed by a tide that flooded the island during "a sudden and violent northeast storm." Wilson continued: "This disaster, however seems long to have been repaired, for they now congregate on the Pea Patch in as immense multitudes as ever."

Some reports of roosting crows over the past 200 years sound uncannily like the descriptions of contemporary crow roosts. Dr. John Godman in his Rambles of a Naturalist, wrote of his observations in 1825 of a roost at his home in Anne Arundel County, Maryland:

The Roost is most commonly the densest pine thicket that can be found, generally at no great distance from some river, bay or other sheet of water which is the last to freeze, or rarely is altogether frozen. To such a roost the crows which are, during the day time, scattered over perhaps more than a hundred miles of circumference, wing their way every afternoon and arrive shortly after sunset. Endless columns pour in from various quarters, and as they arrive pitch upon their accustomed perches, crowding closely together for the benefit of the warmth and shelter afforded by the thick foliage of the pine. The trees are literally bent by their weight, and the ground is covered for many feet in depth by their dung, which by its gradual fermentation must also tend to increase the warmth of the roost. Such roosts are known to be thus occupied for years, beyond the memory of individuals….(Godman 1833)

In the winter of 1916–1917, Charles Townsend MD explored a vast American Crow roost at Castle Hill in Ipswich, Massachusetts, and later wrote detailed descriptions of the roost. At that time, 20 or 30 acres of land at Castle Hill were covered with mature evergreens, mostly European scotch and Austrian pines, and patches of deciduous trees.

He noted that by 3:00 pm, three streams of crows began their flight to the roost, gathering first in the dunes or in the fields below the hill. An hour later, he and his companions saw a flock stretching for two miles that took four minutes to pass their observation point. Sunset was at 4:15 that day and it was dark when many of the birds finally went into the evergreens to roost. He calculated that there were 12,000 birds in the roost (Townsend 1918).

Crow pellet found at the Lawrence Winter Roost. All photographs by Craig Gibson.

Townsend was fascinated by the pellets of indigestible material that the crows disgorged. He collected many pellets from the Castle Hill roost and had them analyzed by the U.S. Biological Survey. Analysis determined that the pellets contained mainly bayberry seeds, along with seeds of poison ivy, staghorn sumac, cranberry, and barberry. (Townsend 1918). A similar pellet analysis from the Lawrence roost is currently being conducted by Dr. Tom French at the Massachusetts Division of Fisheries and Wildlife.

The Lawrence Winter Crow Roost

In the winter of 1989, Eliot W. Taylor first reported American Crows roosting in downtown Lawrence, Massachusetts, a seemingly unlikely location. Lawrence is a city of only six square miles in area, and the Merrimack River, which bisects the downtown area, is lined with many former brick textile mills. The year this roost was established is unknown, but Taylor first noticed the roost on February 2, 1989, when he was driving along Interstate 495, which runs through Lawrence. He saw many crows flying across the road headed into the city and thought, "There must be a roost." He promptly turned off the highway and followed the crows to a cemetery where he estimated 2000 crows (Taylor, personal communication). On other visits to the roost, he reported 4000 crows (Forster et al. 1990), 8000 crows (Forster et al. 1993), and 11,500 crows (Kellogg et al. 2007).

Just after sunset on December 28, 2017, hundreds, if not thousands, of crows pour into a staging area on the west side of the O'Leary Bridge Rt. 28/Broadway by the Great Stone Dam.

Joseph Hogan of Lawrence also reported winter roost numbers to Bird Observer: 5272 crows (Forster and Rines 1992) and 4256 crows (Forster et al. 1994). Rick Heil reported 10,000–15,000 crows in 2009 (Kellogg et al. 2009).

The Lawrence roost also contains flocks of Fish Crows, which are easily identified by their nasal calls. Before heading to the roost, Fish Crows tend to settle into staging areas in various parking lots separate from American Crows. Skip Charette reported the first Fish Crow at the Lawrence roost on January 13, 1994 (Forster et al. 1994).

There have been no recent documented estimates of the total number of American and Fish crows coming into the Lawrence roost. I observed 5000 American Crows on November 16, 2017.

Staging

Prior to entering a winter roost, crows usually fly in small flocks from their daytime feeding areas to one or more staging areas during the afternoon. Most arrive at staging areas that are one or more kilometers from the roost an hour before sunset (Moore and Switzer 1998). On cloudy or windy days, they often start flying earlier. Crows do not appear to do much, if any, feeding in the staging areas.

The National Grid substation on South Canal Street is one of the crows' staging areas. Crows cover the ground, fill the trees, and perch on the utility wires.

Interestingly, crows that are members of cooperative breeding groups—usually many of the permanent resident crows—leave the feeding area independently, do not roost together, and independently leave the roost in the morning (Caccamise et al.1975).

Staging may have evolved to deter persecution and to help keep the roost location secret. Once at the staging area, the crows are social and noisy, with flocks periodically rising and moving to a new spot. At the staging area, the crows may feed, preen, and scan the surroundings (Moore and Switzer 1998). We also have observed some crows going into an almost stupor-like behavior prior to going to roost, as well as at the actual roost. This behavior was particularly noticeable on cold winter days. The birds seemed oblivious to nearby people and hardly moved for long periods of time even when settled on the ground. Unfortunately we are unable explain this interesting behavior.

Staging areas are usually different almost every night. In Lawrence, crows start to pour into the city along the Merrimack River from all directions about an hour before sunset on a winter day. It is a breathtaking experience watching the crows stream in against the background of old textile mills, factories, telephone wires, and lights. They appear immune to the fact that they are settling into a bustling city. No one knows for sure how far away the crows come from. Each night, they seem to choose a different staging area either to the east or the west of their final roosting spot. Every night is like a "Where's Waldo" puzzle. If it is very cold and the river is frozen, many crows will gather to the west of the roost on the ice above the Great Stone Dam. Or they might go to Pemberton Park on the northwest side of the roost. Other nights they may stream to the east of the roost and gather on either the south or north side of the river—in trees, in parking lots, on buildings, and on the ground. One cloudy night, we found them on the hill to the east of the Lawrence General Hospital. The noise is always considerable. There is constant movement of swirling flocks around the staging area.

Silence falls when the crows settle into their overnight roost.

The Roost

Once it is dark, usually half an hour after sunset, the crows enter the roost. In some places, crows may use the same roosting site for many years (Emlen 1938, 1940; Black 1941). The total number of birds in a roost varies from a few hundred to more than 500,000 (Gorenzel and Salmon 1992) to 2,000,000 (Iams 1972). Sometimes, crows settle in such high density that the limbs of the roost trees break.

Crows often roost in coniferous trees. In Lawrence, there are no stands of conifers along the Merrimack River, so the crows use the riverine deciduous trees. They roost either in a line of 30-foot-tall silver maples along the south side of the Merrimack River bordering the New Balance property on South Union Street, or in silver maples or birch trees on the north side of the river. After dark, the lights of the evening shift at the factory illuminate the trees, which appear to be decorated with a thousand black ornaments. Suddenly it is quiet.

Crows leave the roost before sunrise, flying over the Merrimack River.

Departure from the Roost

At sunrise, crows depart from the roost and go out to feeding areas for the day.

But just an hour before sunrise, when the east was becoming faintly lighted, the crows suddenly commenced awakening, and at the same time commenced cawing. The few who led the measure were within one or two minutes joined by the full chorus of 300,000 or more voices, each apparently striving to be heard by all the rest. Never before had I realized the almost infinite possibility of the crow's variable caw in the production of discords. This great noise, which the poetic soul of Audubon conceived to the "thanksgiving" and "consultation," was kept up for twenty minutes before any movement was discernible. (Edwards 1888)

Exploring and Viewing the Lawrence Roost and Staging Areas

Plan to visit the roost on an afternoon any time from November through March. The number of birds will be highest in January and February. Dress warmly, as you will want to have the car windows open. A flask of coffee or tea also can be helpful. Check the time of sunset and plan to arrive at least an hour before. A sunny afternoon is best.

Map of Lawrence Roost and Staging Areas.

To reach the roost, take Interstate 495 to Lawrence and get off at Exit 44. See the map for potential staging areas and for the roost and New Balance factory sites. Travel along Merrimack Street from east to west looking for the gathering flocks. Turn into the parking lot of 280 Merrimack Street and drive to the river. Scan along both sides of the river for gathering crows. If they are along the north side of the river, view them by returning to Merrimack Street and take a right onto South Union Street, then go over Duck Bridge and take your first right onto Island Street. Follow Island Street to the east around the buildings until you reach a parking lot along the river. Look for crows on a small grassy hill (Ferrous Hill), on rooftops, in parking lots, or in the trees along the river. You can return to Duck Bridge (South Union Street) at any time to watch the crows enter the roost.

If the crows are not gathering on the east side of South Union Street, continue along Merrimack Street, crossing South Union so that the New Balance shoe factory will be on your right. Turn onto a dirt road, South Canal Street, just beyond the factory and park your car along the fence. They may be staging at the National Grid and the adjoining truck trailer parking lots. Drive farther along Merrimack, as crows may be scattered on both sides of the road along wires, on rooftops, and in parking lots. Listen to the crows, as you may come across a gathering of Fish Crows. The crows may be in Pemberton Park on the north side of the river between the Parker Street and South Broadway bridges. If the river is frozen, drive farther west and turn right—north—on South Broadway, passing over the bridge; look west over the Great Stone Dam on the ice and in the trees bordering the river.

Half an hour after sunset, the crows will take off in small groups and fly to the north and south sides of the river along South Union Street. Park in the New Balance parking lot on the east side of South Union and walk across the street and out onto the bridge. Once you get to the edge of the New Balance shoe factory, look down into the trees lining the river. Crows, like large black baubles, will be adorning the trees and more crows may still be joining the roost. Walk quietly and slowly along the bridge and you will see the tree branches hanging over the river adorned with more black baubles. Now walk across the bridge and look at the north side in the trees bordering the river—thousands and thousands of crows. You are left to hazard your own guess as to how many!

You may also choose to view the departure of the crows from the roost. This will be more dramatic and very noisy. Arrive an hour before sunrise and follow the directions in the previous paragraph. Stand in the middle of the bridge to watch the crows erupt from the trees on both sides of the river.

Other Roosts in Massachusetts

Currently, there are known large roosts in Framingham and Springfield. American and Fish crows are also known to roost on Martha's Vineyard each night, returning to the mainland to forage during the day.

Crows and their communal winter roosts are fascinating. I encourage readers to visit one to experience the sheer spectacle—the whir of wings, the raucous calls, and the aggregation of thousands of resident and migrant birds against the setting or rising sun.

Addendum

After the February 2018 issue of Bird Observer went into production—about a month after this article was written—the crows in Lawrence disappeared from their traditional roost site near the New Balance factory on South Union Street. On December 27, 2017, Craig Gibson discovered them staging on the frozen Merrimack River to the west of the South Broadway Street Bridge and the Old Stone Dam. After sunset, the crows moved to a new roost site in Pemberton Park on the north side of the river between the South Broadway Bridge and the Casey Bridge off of Amesbury Street. Bob and I visited the staging site around 3:30 pm on Friday December 29, where Bob counted 7,500 crows on the ice and 1,200 crows in the trees lining the river. We followed the stream of crows to their new roost after dusk and every tree along the river and many trees in the parking lot were filled with crows. On January 3, we found the crows roosting in another spot—14,000 of them—in trees on the south side of the river to the west of the dam in the Lawrence Water Treatment plant's parking lot.

Due to the frigid weather of the last weeks of December 2017 and the beginning of January 2018, the Merrimack River had frozen upstream of the Old Stone Dam and the extent of the ice was greater than usual. Perhaps the new roost locations are temporary in response to the extreme cold and the frozen river, and the crows will return to their former roost when winter conditions return to normal. We will continue to monitor the staging and roosting sites of the Lawrence crows.

Acknowledgements

Over the past few years, Wayne Petersen's infectious curiosity and enthusiasm for crows and the Lawrence crow roost, coupled with my characteristic ability to immerse myself in a subject once I get started, along with the generous help of so many friends and other birders, especially my husband Bob Fox, Craig Gibson, and Barry Van Dusen, led to this article. Special thanks go to Craig Gibson, who has become a passionate crow observer and photographer par excellence of the city's crows; and to Jim Berry, who provided me with early records and helped to edit this piece.

References

Black, C. T. 1941. Ecological and economic relations of the crow, with special reference to Illinois. Ph.D. dissertation University of Illinois, Urbana.
Caccamise, D. F., L. M. Reed, J. Romanowski, and P. C. Stouffer. 1997. Roosting behavior and group territoriality in American Crows. The Auk 114:628-637.
Edwards, C. L. 1888. Winter Roosting Colonies of Crows. The American Journal of Psychology. Vol.1 (3): 449-450.
Emlen J. T. Jr. 1938. Midwinter distribution of the American Crow in New York State. Ecology. 19: 264–275.
Emlen J. T. Jr. 1940. The midwinter distribution of the crow in California. Condor 42:287–294.
Forster, R.A., G. W. Gove, and R. H. Stymeist. 1990. Field Records January/February 1990. Bird Observer 18 (3): 174.
Forster, R. A., and M. W. Rines. 1992. Bird Sightings January/February 1992 Summary. Bird Observer 20 (3): 167.
Forster, R. A., M. W. Rines, and R. H. Stymeist. 1993. Bird Sightings January/February 1993 Summary. Bird Observer 21 (3): 176.
Forster, R.A., M. W. Rines, and R. H. Stymeist. 1994. Bird Sightings January/February 1994 Summary. Bird Observer 22 (3): 164.
Godman, J. 1833. Rambles of a Naturalist. Philadelphia: Thomas T. Ash—Key and Biddle, p. 122. [Originally published in The Friend: A Religious and Literary Journal. Philadelphia: The Religious Society of Friends.]
Good, E. E. 1952. The life history of the American Crow Corvus brachyrhynchos Brehm. PhD Thesis, Ohio State University, Columbus.
Gorenzel, W. P., and T. P. Salmon. 1992. Urban crow roosts in California. Proceedings of the Vertebrate Pest Conference 15: 97–102.
Iams, G. 1972. Fort Cobb crow study. Oklahoma City: Oklahoma Department of Wildlife Conservation.
Kellogg, S., M. W. Rines, R. H. Stymeist, and J.R. Trimble. 2007. Bird Sightings January/February 2007. Bird Observer 35 (3): 191.
Kellogg, S., M. W. Rines, R. H. Stymeist, and J. R. Trimble. 2009. Bird Sightings January/February 2009. Bird Observer 37 (3): 182.
Moore, J. E., and P. V. Switzer. 1998. Preroosting aggregations in the American Crow, Corvus brachyrhynchos. Canadian Journal of Zoology 76:508-512.
Sibley, D., C. Elphick, and J. B. Dunning, Jr. 2001. The Sibley Guide to Bird Life and Behavior. New York: Knopf.
Townsend, C. W. 1918. A Winter Crow Roost. The Auk 35(4) 405–416.
Veit, R. R., and W. R. Petersen. 1993. Birds of Massachusetts. Lincoln: Mass Audubon.
Wilson, A. 1811. American Ornithology, Vol. IV, pp. 82–84. Philadelphia: Bradford and Inskeep,

At eight years old, Dana Duxbury-Fox asked for her first bird book and has been an active birder ever since. She graduated from Cornell University, and taught biology in India for two years. For many years, she has been researching ways to protect the Common Loon with the Loon Preservation Committee in New Hampshire. Now, winter crow roosts have caught her attention. Dana, her husband Bob, and Craig Gibson are continuing their research on the Lawrence Crow Roost.

February 2018

Birding Minute Man National Historical Park

Route #1 Meriam's Corner Route

Basics: 1.7 miles round trip, easy terrain Best: All year NOTE: This route may be icy in winter

Route #2 Brooks Farm Boardwalk Route

Basics: 1.5 miles round trip, easy Best: Spring, summer; sections in winter

Route #3: Hartwell/Vernal Pool Loop

Basics: 1.2 miles: Vernal Pool Trail is uneven muddy terrain, other portions are easy. Insect repellant is suggested. Best: Spring, early summer; sections in fall and winter

Other Birding Spots in the Park (East To West)

Future Conservation Efforts and eBird Data

Acknowledgements

Resources

Red Crossbills in Massachusetts and the Northeast: A Possible Irruption in 2017–2018

Natural History

Red Crossbill Speciation

Recent Red Crossbill history in Massachusetts

Where to Look in Massachusetts and the Northeast

References

A History of Winter Crow Roosts and a Visit to a Roost in Lawrence, Massachusetts

Early History of Winter Roosts

The Lawrence Winter Crow Roost

Staging

The Roost

Departure from the Roost

Exploring and Viewing the Lawrence Roost and Staging Areas

Other Roosts in Massachusetts

Addendum

Acknowledgements

References

Basics: 1.7 miles round trip, easy terrain
Best: All year
NOTE: This route may be icy in winter

Basics: 1.5 miles round trip, easy
Best: Spring, summer; sections in winter

Basics: 1.2 miles: Vernal Pool Trail is uneven muddy terrain, other portions are easy. Insect repellant is suggested.
Best: Spring, early summer; sections in fall and winter