Neil Hayward and Robert H. Stymeist
A Note on Taxonomy
Bird Observer follows the taxonomy published by the American Ornithological Society (AOS). The AOS was previously known as the American Ornithologists' Union (AOU) before its merger with the Cooper Ornithological Society in October 2016. Each summer the AOS's Committee on Classification and Nomenclature of North and Middle American Birds (NACC) publishes an annual supplement to its bird checklist. We have been using the 56th Supplement to the 7th edition, published in 2015. From this edition, we'll jump ahead to the most recent supplement, the 58th, published in July 2017.
One of the biggest changes introduced in the 57th Supplement is a major reshuffling of the family deck. Notably, pigeons, cuckoos, goatsuckers, hummingbirds, and swifts move "forward" toward the "front" of the field guide. These families now appear before shorebirds and loons! Many of these changes are based on new genetic research. The 58th Supplement has two taxonomic changes relevant to Massachusetts: Thayer's Gull is no longer a species in its own right but rather a subspecies of Iceland Gull, and Le Conte's Sparrow is now LeConte's Sparrow (the 19th century entomologist apparently didn't write his name with a space in it). With each annual AOS supplement, we'll update the taxonomy here, and explain any changes that impact the way we list species recorded in Massachusetts.
Brown Thrasher by Sandy Selesky
September and October are exciting months for birders, and the weather during this period was near perfect. September temperatures averaged 67 degrees in Boston, two degrees above average, although temperatures away from the coast were much warmer. The high mark for September was 88 degrees on September 5, and the low was 52 degrees on the last day of the month. Rainfall measured 3.73 inches, only 0.3 inches above the average for Boston. The most in any 24-hour period was 1.55 inches on September 30. By September 22, Hurricane Jose was downgraded to a tropical storm, even though a wind advisory and a prediction of heavy rain were issued for Cape Cod and the Islands. Lucky birders at Race Point in Provincetown during that period recorded an array of unusual birds.
October 2017 was the second warmest October on record. The official average in Boston was 61.4 degrees, seven degrees above the average, and only 0.1 degrees below the record set in 1947. The high was 80 degrees on October 5, and the low was 40 degrees on October 17. Rainfall was 4.14 inches, just about average for the month, with much of it (1.71 inches) falling from the night of Tuesday, October 24, through the morning of Thursday, October 26, and causing flash flood alerts for most of eastern Massachusetts.
Figure 1. Weather and reverse migration, October 2017. Average wind speed (dotted lines) and wind gusts (solid bars) for Logan Airport (weather station KBOS) are shown for each nocturnal flight (6 pm through 6 am). Average wind direction for the period is shown below together with arrivals of potential "southern" reverse migrants. Data from www.eBird.org and National Oceanic and Atmospheric Administration.
GEESE THROUGH IBISES
Wild goose chases kept Massachusetts birders busy during this period. With the exception of Ross's Goose, every species of goose on the Massachusetts state list was recorded in October.
The highlight, a Pink-footed Goose, was discovered in Hadley on October 30. Pink-footed Goose is undergoing a population explosion in eastern Greenland and Iceland, from which birders in the Northeast are clearly benefiting. The first Massachusetts record was in January 1999 at Dennis. It took almost a decade to the day for the second bird to arrive (also on the Cape), but since then Pink-footed Goose has been annual and has been recorded in seven counties (though notably still absent from Berkshire County). This year's bird may be the same individual reported from Caribou, northeast Maine, on September 26, the earliest arrival date for the United States. A Barnacle Goose was present in Westfield from October 27 through the end of the month. Barnacle Goose is experiencing similar population growth and has been recorded in Massachusetts in 13 of the 17 years this century.
There's nothing quite like a species split to refocus attention on an otherwise common bird. That's been true of Canada Geese since 2004, when a split elevated Cackling Goose to the species level. Thanks to greater scrutiny from local birders, the more diminutive "Cacklers" are now regularly found among winter flocks of Canada Geese. During his period, birds were reported from at least six locations. These records presumably pertain to the pale Richardson's (hutchinsii) subspecies that breeds in Canada's Arctic Archipelago and winters south of the Great Plains.
Last but not least among the geese, Brant migrate through our state in October, heading to wintering grounds along the Atlantic coast from southern Maine to Virginia. Brant are rarely seen far inland, and a flock of 19 in Hadley on October 31 was unusual. Rarer still, a "Black Brant" was recorded at Gloucester on October 28. This dark-bellied subspecies (nigricans) winters on the Pacific Coast and has been recorded only seven times this century in Massachusetts, all singles in October and November (presumably migrants), and all seen in Plymouth.
A male Eurasian Wigeon discovered on Nantucket on September 13 was an early surprise. This wintering vagrant is generally rare before October. Harlequin Duck is similarly rare before October, and the first bird of the season was early, a male at Plymouth on September 21. King Eiders were reported from four locations. All three species of scoter were found inland in October, which is characteristic of their fall migration. High counts at Quabbin reflected their typical relative abundance: Black Scoter 211 (usually the most commonly encountered inland), White-winged Scoter 32, and Surf Scoter 12 (the least common inland).
Common Nighthawks completed their fall migration through the state in early September, with the main flight following the Connecticut River Valley. Chimney Swifts follow the same temporal pattern as Common Nighthawks with most passing through in early September. The records of swifts in October likely reflect reverse migration from the south, with birds opportunistically flying downwind. Figure 1 shows Chimney Swifts occurring on days with south or southwest winds. Reverse migration also explains the late records of Yellow-billed Cuckoo, a species that has vacated the state by early October. A period of sustained south, southwest, and west winds at the end of the month brought multiple Yellow-billed Cuckoos.
There were no reports of Common Gallinule breeding in the state this year, and so the September and October records likely show migrants. A count of five birds on South Monomoy on September 2 is the highest count for the Cape this century. Summering Sandhill Crane pairs in Tolland and Burrage Pond continued into October, as did the family that fledged two young at Worthington.
The shorebird of the period (and the year!) was a juvenile Common Ringed Plover discovered on September 11 at Gooseberry Neck. The bird was initially identified by its distinctive poo-ii call. The visual field marks separating this bird from the very similar Semipalmated Plover are more subtle; the bird is stockier with more dark feathering in the loral area meeting the gape; a broader, more uneven supercilium; a colder, pale-edged back; and, if visible, a lack of extensive webbing between the toes. This is the fourth record of Common Ringed Plover for the state, with two previous records in September, including a 2010 bird at Chatham also found on September 11. It's unclear how long this year's bird stayed. While there were many reports for several days after the bird's discovery, photographic documentation exists only for the first two days.
The first Purple Sandpiper of the season was spotted at Plum Island on October 1, at least two weeks ahead of schedule. With the notable exception of a record at Andrews Point on September 26, 2010, this is one of the earliest winter arrival dates for this species in the state.
Tropical Storm Jose settled to the southeast of Cape Cod on September 20, bringing with it days of gale-force winds from the northeast and cancelling the Brookline Bird Club overnight pelagic. However, the storm clouds had a silver lining for those buffeted by the winds at Race Point, where a spectacular array of storm-blown birds streamed east out of Cape Cod Bay. On Saturday, September 23, observers recorded three South Polar Skuas (a record count for Race Point), 52 Pomarine Jaegers, 82 Parasitic Jaegers, three Long-tailed Jaegers, a first-of-the-season Common Murre, two Sabine's Gulls, one Franklin's Gull, one Sandwich Tern, 294 Northern Fulmars (a record count for September), almost 8,000 Great Shearwaters, and eight Leach's Storm-Petrels.
The highlight of that day was a first for Massachusetts (pending MARC approval): a Short-tailed Shearwater photographed by visiting pelagic birder and author, Steve Howell. Incredibly, three weeks later, a Short-tailed Shearwater was photographed again at Race Point. This dark shearwater breeds in Australia, where it's commonly known as a "muttonbird" (the young are harvested for food). Superficially similar to the larger Sooty Shearwater, Short-taileds have a smaller, thinner bill, a steeper forehead, and darker underwings with dark primary coverts. The shearwater spends its austral winter (our summer) in the Pacific, ranging as far north as the Bering Sea and the Arctic Ocean before returning to the southern hemisphere by way of the West Coast. It's exceptionally rare in the Atlantic Ocean with just three reports: a sight record in Virginia (January 1998), a specimen collected in Florida (July 2000), and a record from Bahia, Brazil (May 2005). Intriguingly, the day before the 1998 Virginia sighting an all-dark shearwater was reported here at First Encounter Beach. Initially considered an unseasonal Sooty Shearwater, this "large, dark Puffinus shearwater" [the genus Puffinus was split in 2016, with Short-tailed Shearwater adopting the new genus, Ardenna] could have been the same species that would take almost 20 years to be seen again.
The tropical storm had one surprise left. The following Tuesday, September 26, a Masked Booby was picked up on a beach in Wellfleet. This is the second record for Massachusetts and the first on state soil. (The first record was photographed on September 10, 2015, in Atlantis Canyon by the captain of the Helen H., while fishing.) Despite extensive medical care at Wild Care, Eastham, the bird passed away on October 2. The body was donated to the Museum of Comparative Zoology.
A first winter Mew Gull was a one-day wonder at Lynn on October 27. The bird was identified to the European subspecies canus ("Common Gull"), which is more regularly reported here than the western North American brachyrhynchus. Mew Gull is almost annual in the state, although this year's four records are unprecedented.
The challenge of attracting large, big-mouthed water birds to the state this summer has definitely been more of a case of peli-can than peli-cant. The "Summer of the Pelican" continued with the North Shore Brown Pelican settling down to spend October in the Boston Harbor. Last period's American White Pelican continued its vacation on Martha's Vineyard until September 28.
A count of five Cattle Egrets at Gill in the final week of October was a record for Franklin County (previously only singles). A White Ibis that spent two days in Northampton this October was noteworthy; the species is less than annual to the state and very rare away from the coast.
VULTURES THROUGH DICKCISSEL
The fall migration of hawks through our region starts in earnest during this period. Hoping to witness a big flight, hawkwatchers congregate on favorite sites, notably Mount Tom in Holyoke, Mount Watatic in Ashburnham, and Wachusett Mountain in Princeton. The majority of migrant hawks in the fall (nearly 85 percent) are Broad-winged Hawks. This year Wachusett and Watatic tallied 15,201 Broad-wings, 5,226 more than in 2016. Other noteworthy reports from Wachusett included 110 Bald Eagles, 132 American Kestrels, and 38 Peregrines. Golden Eagles were noted from two locations, the same as last year during the same period. Saw-whet Owl populations are highly cyclical and are often based on the small rodent populations to our north; only five Saw-whets were reported this fall. Last year, Drumlin Farm Wildlife Sanctuary in Lincoln alone banded 332 during the same period.
Passerine migration is well underway during this period, and birders were out in force. Many considered this one of the best fall migrations. Rarities this year included an Ash-throated Flycatcher that spent at least six days in Middletown, a Scissor-tailed Flycatcher in North Truro, LeConte's Sparrows at Bolton Flats and Falmouth, a Harris's Sparrow in Scituate, Summer Tanagers in Rockport and Orleans, and a male Painted Bunting in Barnstable. There were 33 different warbler species noted during the period, which included two Black-throated Grays, two MacGillivray's and two Yellow-throated. Other exceptional reports were three Golden-winged, over 20 Orange-crowned, and over 40 Connecticut Warblers. Clay-colored Sparrows were noted in 35 locations, up from only 14 localities during the same period last year. Other sparrow highlights included eight different Lark Sparrows and several reports of Nelson's Sparrows, including one from Sheffield in western Massachusetts.
The same strong southerly winds at the end of October that brought cuckoos also brought other reverse migrants to the Northeast including Yellow-throated Warbler and Summer Tanager (see figure 1), as well as many reports of vireos and warblers, birds that should have been long gone from our area.
Not only did we bird during the day, but many of us stayed up at night to listen to the calls of migrant song birds passing overhead. (Note the new abbreviation in our species list, nfc, for birds identified by their nocturnal flight calls.) Many of these calls, especially those of the thrushes, are distinct and diagnostic. Evans and O'Brien's excellent Flight Calls of Migratory Birds on CD-ROM is a great place to start, and is available online at http://oldbird.org/pubs/fcmb/start.htm.