Birds Have Ways to Cope With The Cold Weather This hardy male northern flicker has been surviving the brutal winter weather in northern Door County. Any time one sees a bird here in the depths of winter, that nests in this region and whose summer diet consists largely of ants (45%), you immediately begin to wonder how they can do it. Our friends Nancy and Bob from northern Door County have had a male common flicker (told by its black mustache) at their place for several weeks. In fact he was still there on a recent day when the wind-chill factor dipped to around a minus 30 degrees F. The bird has been feeding on beef suet at their feeders and also making frequent use of the heated water. Growing in the wild nearby are other native plants whose fruits this bird is known to make use of in winter. Included are especially poison ivy, Virginia creeper, dogwood, wild cherry, purple nightshade, staghorn sumac, mullein, ragweed, wild grape and juniper. Interestingly the so-called berries of poison ivy rank at the top of their favorites during the cold season. Two other birds are also well-known for their fondness of these seed-containing fruits, the black-capped chickadee and downy woodpecker. You can be assured that plenty of the seeds go through the birds’ digestive systems and end up being planted, via the birds’ droppings, well away from where the berries were obtained and consumed. Common juniper shrubs, some heavily laden with fruit at this season, are extremely abundant in the area where the flicker is being seen. Cedar waxwings, bohemian waxwings and the Townsend’s solitaire, a rare visitor from the West in some winters, are known for their fondness of the juniper berries (actually modified cones containing seeds). Under ordinary circumstances the common flickers don’t arrive in our region until very late April into early May. Those that appear in early April very likely are birds that had overwintered. For some unexplained reasons there appears to be an increasing number of flickers remaining in Wisconsin in winter in recent years. Since 1968, according to Sam Robbins’ great book, "Wisconsin Birdlife," Christmas Bird Counts have turned up anywhere between seven and thirteen individual flickers in December in Wisconsin. The majority of sightings are in southern counties. However, Bayfield Co. (the most northerly where a flicker wintered) had one in 1980, Vilas Co. in 1944 and Marinette Co. in 1969. No one knows for sure how many of these wintering flickers survived through the entire cold season. Flickers, one of the best known woodpeckers in America, make use of roosting holes at night as do most woodpeckers, chickadees, nuthatches and several other species including bluebirds. Fluffing their feathers outward at the bottom of a tree cavity, away from the ravages of a howling wind, these birds somehow manage to survive upwards of 14 hours in this position. I wonder if studies of the flicker’s nighttime body temperature have been made as have those of the chickadee. Interestingly the daytime body temperature of a chickadee is around 109 degrees. F. and its heartbeat approximately 1000 per minute. During the night its heartbeat slows down to 500 a minute and its body temperature falls between 10 and 12 degrees F., to around 98 degrees F. Slowed down to this extent the chickadee is able to use about 20% less energy thereby raising its chances considerably of surviving a long sub-zero night. Our friends, Jim and Mary, living adjacent to Bob and Nancy, had eight eastern bluebirds winter on their land last year. Surely the fruits of staghorn sumac and common juniper shrubs helped sustain those birds throughout the winter. I wouldn’t doubt that all eight huddled together in one birdhouse every night in order to conserve body heat. This species is well known for doing this. One of my favorite bird references, "The Life of Birds," by Joel Carl Welty of Beloit College states that in most species of birds, if the body temperature falls to 71 Degrees F. they apparently will die. Interestingly under normal conditions a bird’s body temperature falls around 1.8 degrees F. for every drop of 18 degrees F. of the surrounding air. However this changes drastically when the air temperature drops below freezing. There is another feature of winter survival that very likely all birds familiar to us at the feeders make use of – shivering, non-stop. This increases a bird’s heat production when it is at rest by converting muscular energy into heat. However the used energy must soon be replaced which hopefully the birds can accomplish by eating rich high-energy foods. Birds in general have high concentrations of glucose in the blood, about twice that of humans. Niger seed, black oil sunflower seeds, beef suet and the "marvel meal" (peanut butter mixture) we and others feed to the birds are good high-energy foods. Some birds including redpolls and evening grosbeaks can store relatively large amounts of seeds in their well-developed crops, an unusual strategy that enables them to survive 14-15-hour nights out in the open, away from food with the temperature as low as 35 to 40 degrees below zero F. How we marvel at birds putting up with the deep winter cold 24 hours a day while we begin to shiver when the indoor temperature drops to 68 degrees F. What softies we are! Three cheers for the birds! This column appeared in the Door County Advocate on 01/31/2004. © Copyright 2004 Roy Lukes. All rights reserved.