Birds utilize a number of behavioral adaptations that afford them some protection from frigid air such as we have been experiencing lately. They include sunning (turning their backs to the sun, exposing the largest surface of their bodies to the heat), shivering, tucking (placing one foot up inside feathers while standing on other leg, or squatting to cover both legs and feet with feathers; tucking their bill into their shoulder feathers and breathing air warmed by their body), roosting together in small groups (often in a small cavity, so as to conserve heat) and, most obvious of all, fluffing themselves up (creating air pockets that are warmed by body heat).
While feathers serve many purposes, from helping to attract a mate to providing camouflage, one of the most important jobs they have in winter is to keep a bird warm and dry. A bird’s body heat (the average bird’s body temperature is 105 degrees Fahrenheit), warms the air between its feathers. Birds fluff up in the cold to trap as much air in their feathers as possible, as the more trapped air, the warmer the bird. They can appear two or three times larger than they appear on a 32 degree day. This insulation is effective because it also is a barrier to water. The oil that birds apply to their feathers when they preen serves to waterproof the feathers. (Photo: Dark-eyed Junco)
Even though signs as well as sightings of active bears are plentiful, and black-oiled sunflower seeds are an open invitation for them to visit and potentially become “nuisance” bears, many devoted bird-lovers have already hung out feeders in hopes of luring feathered friends closer to their home. Throughout northern New England so few birds have been attracted to these feeders that they have remained full, some not having been refilled since September. Our usual fall and winter visitors appear to have all but vanished, and concern has been growing amongst those who feed birds.
Those familiar with bird feeding habits know that in the fall, when seeds are abundant, feeder visits by resident birds typically slow down. However, this year, at least anecdotally, appears to be extreme in this regard. Warm weather extending into November certainly has lessened birds’ food requirements. But having sunflower seeds sprout in your feeder before the need to replenish them arrives is unusual, if not alarming.
Dr. Pam Hunt, Senior Biologist in Avian Conservation at New Hampshire Audubon, recently shared some of her personal research with the birding world (UV- Birders). Hunt has conducted a weekly, 10 km-long, bird survey near Concord, NH for the past 13 years. In addressing the current concern over a lack of feeder birds, she extracted the data she had accumulated on 12 common birds (Mourning Dove, Downy Woodpecker, Hairy Woodpecker, Blue Jay, Black-capped Chickadee, Tufted Titmouse, White-breasted Nuthatch, White-throated Sparrow, Dark-eyed Junco, Northern Cardinal, House Finch, American Goldfinch) over the last 13 falls, focusing on the period between Oct 1 and Nov 15. After extensive analysis, Hunt concluded that there has not been a dramatic decline in the number of birds this year, relative to the averages of the past 13 years. One cannot argue with scientific evidence (except for, perhaps, #45), but it does seem mighty quiet on the western (northeastern?) front this year.