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
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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.
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.