Birds : Survival Skills
The first week of the new decade featured the 50th Martha's Vineyard Christmas Bird Count (CBC), which due to fabulous weather (not) was postponed until the last day of the count period, January 5, 2010. Because this was written before the results are in the count will be discussed in a future column. If other area counts are any indication, this year's tally will be on the low end of the spectrum.
Neighboring CBC results
On Nantucket, the CBC was conducted on New Year's Day. Conditions were not horrible as the wind stayed to a dull roar, but the sun never made an appearance. Overcast skies with limited visibility were the rule, which makes finding over-wintering land birds very difficult. Nonetheless the CBC produced 118 species with many highlights that are typical of this island that is farther out to sea.
Vineyard birders will be impressed by numbers such as 180 lesser black-backed gulls - this being the most on any CBC in North America as well as 50 Iceland gulls, 3 little gulls, 2 black-headed gulls, and you get the picture that Nantucket is better for seeing gulls in the winter than the Vineyard. A yellow rail, one of the sneakiest, scarcest, and most desired to see by birders on this continent was recorded again for the third year in a row. This individual flew some 50 yards in a marsh, allowing many observers the chance to see its small size and white wing patch.
The Outer Cape CBC was rescheduled and conducted on December 27. A paltry 111 species were recorded, but nonetheless some great birds were detected, including two new species for this long-running CBC. The new birds were a black vulture seen in Brewster and a summer tanager coming to a feeder in Orleans. A painted bunting female that has been visiting a feeder for more than a month in Orleans was also recorded.
The Stellwagen Bank CBC, a pelagic count, was conducted on the research vessel AUK on December 31 departing from Plymouth and venturing out to run a series of transects on Georges Bank. Impressive numbers of alcids including 30 common and 35 thick-billed murres, a razorbill, and two dovekies were recorded. Lots of black-legged kittiwakes, northern gannets, two northern fulmars and both Iceland and Glaucous gulls were seen, despite rain and snow showers for much of the day.
Winter tightens grip
As winter progresses, 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 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 continue in these coldest, darkest months. As soon as the birds have found your feeders, they incorporate it into their pattern for surviving. 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 such as golden-crowned kinglets and black-capped chickadees - weighing in at approximately 6 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. 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.
For the aforementioned 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, incredibly fast, intelligent, prey 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, always has been, but the odds for survival of immature raptorial birds is low.
Until next time - keep your eyes to the sky.