BirdWatching Column: Fueling the Metabolic Furnace
[CORNER TURNDOWN] NEW!
[OVERLINE] attracting birds BY LAURA ERICKSON
[HED] Fueling the furnace - O R - Fueling the metabolic furnace
[DECK] Provide high-calorie meals that will help birds survive the winter - O R - You can provide high-calorie meals that will help birds survive the winter
[488/478 WORDS] When Editor Chuck Hagner asked me to write this column, I was thrilled. Contributing regularly to my favorite bird magazine is a huge honor. I¹ll focus primarily on backyard issues, especially regarding attracting birds.
I live in Duluth, Minnesota, where winters can be harsh. One February a loud bang, like a shotgun, woke me in the middle of the night. My husband and I searched but didn¹t find anything. Next morning the thermometer read -40°F. When I opened the drapes, our thermal-pane window had a diagonal crack, corner to corner.
Temperatures extreme enough to damage houses didn¹t seem to bother my chickadees, redpolls, nuthatches, woodpeckers, and other birds. If I¹d had a tiny rectal thermometer and a willing chickadee, I could have verified that underneath its feathers, its body was at least 104°F – fully 144 degrees warmer than the air just millimeters from its heart, thanks to that metabolic furnace. Thick down feathers provide superb insulation for birds, but in the same way that the most insulated cabin will freeze without a source of heat, birds must burn fuel, in the form of food, to maintain their body temperature. At night, chickadees allow their temperature to drop about 15 degrees to conserve energy. At first light, they start shivering to warm up quickly. That requires a sudden burst of energy.
That¹s why in winter I feel a special urgency to provide high-calorie meals. Black-oil sunflower seeds are perfect – high in energy, with thin shells that don¹t take much work to open. Virtually no House Sparrows or starlings winter in my neighborhood. If they are a problem near you, try striped sunflower seeds, which have more rigid, thicker shells and are harder to crack open. (Of course, because House Sparrows are functionally illiterate and haven¹t read about this, some have gone and figured out how to open striped sunflower seeds. In many places, however, switching is a simple solution for problem birds.)
Unlike us humans who have to worry about cholesterol, birds readily metabolize fats. They benefit from the high fat content not only in black-oil sunflower, but also in suet. In the north woods, some deer hunters set out an entire rib cage. I¹ve watched Boreal and Black-capped Chickadees, Gray and Blue Jays, nuthatches, and all manner of woodpeckers clinging to a ribcage suspended on a wire from a large tree limb. It was slowly spinning; the birds looking like happy diners at a revolving restaurant. In urban and suburban areas, neighbors might not approve of ribcages dangling in a backyard, but a rib or leg bone discreetly placed can provide both calories and calcium for a winter feast.
Studies on Wisconsin chickadees have proven that chickadees with access to feeders survive severe winters in higher numbers than those that don¹t. Calorie-rich feeder fare helps our winter birds maintain their body temperature while warming our hearts.
[BIO] Laura Erickson is a bird rehabilitator, science editor, and the producer of the radio segment ³For the Birds.² She is the author of Twelve Owls, The Bird Watching Answer Book, 101 Ways to Help Birds, and other books. You can find more of her writing about backyard birds on our blog.
[PULL-QUOTE - SHORT] “Chickadees with access to feeders survive severe winters in higher numbers than those that don¹t.”
[PULL-QUOTE - LONG] “At night, chickadees allow their temperature to drop about 15 degrees to conserve energy. At first light, they start shivering to warm up quickly. That requires a sudden burst of energy.”