|These two long-billed dowitchers, currently fattening up on the mudflats of Katama Bay for further migration, are running very late on a southward journey that likely started from the Arctic coasts of Alaska, Nunavut, or even Siberia.
Winter no picnic for birds
As winter progresses, despite the relatively benign conditions and mild temperatures, over-wintering birds have continually less stored fat in reserve. This fat is invaluable; it is a metabolic life preserver, if you will, to get the bird through a severe winter storm when there is no access to food. The birds are able to metabolize it when needed but as the winter continues the reserve grows smaller and the margin for error constantly shrinks.
This is why those of you who feed birds must reliably come through for them in these coldest, darkest months. As soon as the birds have found your feeders, they incorporate them into their pattern for surviving the upcoming, harshest months. An empty feeder is a life-threatening disaster for land birds that have come to depend on it during the past weeks.
Surviving the winter is a hard task. It is tough on all living creatures and from this writer's perspective it seems the birds that actually flew south are on to something. Nonetheless, it is fascinating and remarkable to think that these tiny feathered animals, birds like golden-crowned kinglets and black-capped chickadees, weighing in at approximately six and 11 grams respectively, can survive at all in below freezing temperatures.
Studies have been conducted and attempted to determine the caloric intake needed by these birds to not only forage for food all day but to fuel them through the long winter night while maintaining their incredible core temperatures that range more than 10 degrees higher than our own. In order for these small birds to survive and maintain a core temperature far exceeding the 98.6 degrees Fahrenheit of humans, they must consume about three times their body weight, on a daily basis. Imagine for a moment that you had to eat food equivalent to three times your own body weight, today, tomorrow, the next day and so on. Take a good look at the next black-capped chickadee you see and give it a mental thumbs-up for the wonder of its life and its survival skills.
Learn or perish
For the afore-mentioned birds, finding a reliable and available food supply is tough enough. Now look for a moment at the brutal challenge for a first winter hawk, specifically a falcon or member of the genus Accipiter. Still learning flying skills and getting more experienced with each meal, these birds must learn as they go, or perish. The difficulty of capturing fast-flying, intelligent, prey items can't be overstated. These birds must eat and it is a lucky (skillful) few immature birds of prey that will survive their first winter. It is nature's way and always has been, but the odds for survival of raptorial birds low.
The greatest activity at this season, in the outdoors, is on the waters surrounding the Island. The Vineyard is blessed with staggering numbers of wintering waterfowl at nearly every point that sticks out from the Island. The waters between Chappaquiddick in Edgartown and Nantucket Island play host to more over-wintering sea ducks, in the form of common eiders and all three scoter species, than any other on the east coast. A visit to Wasque with a spotting scope at dusk is worthwhile to view the tens and even hundreds of thousands of ducks that are often visible, flying, moving over the shoals in flocks that look like smoke on the horizon.
The best and only real way to get a look at this massive aggregation of ducks is to fly over in an airplane. By boat they continually flush and fly off creating a half-mile circle of flying birds wherever the boat goes. Massachusetts Audubon has been conducting aerial surveys for the past two winters in an attempt to see how many birds use this area, the studies brought about by the proposed construction of a massive wind project over 24 square miles of Nantucket Sound, and has found it to be the most significant area in New England with hundreds of thousands of sea ducks utilizing the area.
The birds congregate here because the water quality is good and the current is strong, which keeps the area free of ice in all but the coldest of winters, but mostly because of the abundant food resources created by blue mussel beds that are prolific. Huge beds of fast-growing blue mussels are the sustenance that allows the birds to winter in large numbers. The shallow water, constantly churning rips and currents, expose vast areas of mussels to the hungry birds, making for easy pickings. It is a perfect place for them - the most important winter home for several species in this part of the world - and has been host to literally millions of birds over the past decades.
Phyllis Conway of Chilmark reports that on Jan. 6, 2006, near Stonewall Pond she had four eastern bluebirds arrive at her bird bath for a drink. The next day, a very orangey Baltimore oriole checked out the same birdbath. This oriole has been hanging out around Stonewall Pond and has a regular circuit that takes it from Andy Goldman and Susan Heilbron's feeders to Trudy Taylor's on the west side of Stonewall Pond to the Conways' feeder and bird bath on the northeast side of the pond.
Lastly, Laurel Reese, over-wintering at Katama in Edgartown, spotted two long-billed dowitchers on the flats on Norton's Point on Jan. 8. She managed to convey the information to Lanny McDowell of West Tisbury who got excellent photographs of these shorebirds, which are extremely rare on Martha's Vineyard, especially in the middle of winter. There are two very similar species of dowitchers in North America, and birders are still figuring out how to separate them conclusively, at certain times of the year. Their calls are distinctive, however, and Lanny heard the birds give the calls of the long-billed dowitchers.
Until next week - keep your eyes to the sky.
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