Martha’s Vineyard birders take a year-end accounting

Of the 121 species that were listed in this year's CBC, common eider were the most plentiful, even though their numbers are way down from the recent past.

Last Saturday, December 29, approximately 60 birders took to the field for the 52nd Vineyard Christmas Bird Count. Additional observations came from about 14 “feeder watchers,” according to count coordinator Rob Culbert. Despite the onset of a steady rain around 2:30 in the afternoon, the combined efforts of these participants tracked down more than 21,000 individual birds representing 121 species, according to a preliminary analysis provided by Mr. Culbert.

The Vineyard count was part of the 113th continent-wide Christmas Bird Count (CBC), a “citizen science” project run by the National Audubon Society. Now comprising counts taking place in more than 2,000 “count circles,” each 15 miles in diameter and centered on a fixed point from year to year, this larger effort enlists tens of thousands of volunteer observers to locate, identify, and count as many birds as possible in a single day. Local factors such as the number and skill of participants available or the weather on count day mean that results for any individual count may vary widely from year to year. But such variability evens out over time and space, and viewed at the continental scale over the long term, CBC data provide a powerful research tool for monitoring bird population trends and wintertime distribution.

The local Island effort is unique in that we use the outline of the Vineyard, rather than a circle, to define the count area. Our roughly 100 square miles is substantially less than the 176 square miles of a regulation circle. But Vineyard counters have the advantage of a community in which birding is especially popular, as well as a locale with a well established record for hosting avian diversity, abundance, and rarity.

Organizing this year’s count was complicated by the fact that the Nantucket count was scheduled to take place the day after the Vineyard event. Due to the complexities of travel to or between the Islands, many birders who might otherwise have participated in both counts had to settle for one or the other. The Vineyard CBC, therefore, went ahead without some of its usual talent, such as legendary birder Vern Laux, long a Vineyarder but now an inhabitant of the Wrong Island. Many mainland birders also opted for ACK at the expense of the Vineyard. The fact that it was mostly home-grown talent making up the three-score observers for the Vineyard count testifies to the popularity of birding among Island residents, as well as Mr. Culbert’s efforts at rounding up participants.

The highlight of this year’s count was most emphatically an Allen’s hummingbird tallied at a private residence off of Lambert’s Cove Road. This species, normally a bird of the California coast (in summer) and Mexico (in winter), was found several weeks ago visiting late-season flowers and a hummingbird feeder. This was the first Allen’s hummer ever found on the Vineyard, and only about the fourth ever in all of Massachusetts. The family hosting this rare visitor coddled it with warmed nectar in their hummingbird feeder, helping it survive until count day (and, hopefully, beyond).

In most respects, though, participants meeting at the post-count tally on Saturday evening seemed to feel that this year’s count fell somewhere between dull and average. In particular, numbers of common eider and our three species of scoter have declined by an order of magnitude from the huge numbers regularly tallied just a few years ago. (Most likely, the large flocks of ducks depleted their food supply and have moved elsewhere in the region; once local mollusk populations have recovered, our duck numbers may increase again.) And many “semi-hardy” species — birds like gray catbird, rufous-sided towhee, hermit thrush, and winter wren — were scarce this year, perhaps because the generally mild autumn hasn’t yet driven all of these birds south to our latitude.

Despite the decline in numbers, though, common eider was still the most numerous species of the count, with 1,354 tallied. Bufflehead, at 1,330, was second in abundance. Since a high percentage of the Vineyard’s shoreline gets surveyed, and conditions for coastal viewing were spectacular, these figures may reflect actual numbers fairly accurately.

In contrast, a bird like winter wren (only four were found) surely got under-counted. There are thousands of little patches of habitat that could host this bird on the Vineyard; counters could only visit a portion of those, and even when you look for it, this tiny, secretive wren usually chooses to stay hidden. Still, because of the year-to-year consistency of bird count procedures, it is likely that numbers for this species truly were lower than usual this year.

My own personal high point was spotting a Baltimore oriole at Sheriff’s Meadow Preserve in Edgartown. The bird had been previously reported by other observers and may have been a migrant that had been blown back north by hurricane Sandy.

Moments after this bright orange bird popped up onto the high point of a shrub thicket, a hawk came out of nowhere to attack it. I couldn’t see the outcome — a tangle of hawk and oriole fell down into the interior of the thicket — but the unusual sighting and its violent conclusion just seconds later shows why birders spend an entire cold day in winter out in the field. You never know what you’ll find, and like gamblers of any sort, birders are driven by the hope that the next pond, thicket, or field will hold a surprise.