What about the Little Birds in the Cold?
I don’t know why it surprises me, but it seems that, over time, many of the most interesting “You really should think about following up on that!” questions are from the mouths of babes.
Case in point:
Homey and I were in my office comparing notes on snow and cold and families right after that last eastern Washington post-snowfall cold snap. “We are really grateful to have a dry, warm house and plenty of food. And we don’t often think about the outside critters. The other morning we were all in robes drinking hot coffee and hot chocolate, just sort of staring out at the little birds at our feeder and talking about the bitter cold only inches away on the other side of the window. Our little boy’s nose was against the glass, and our four-year-old was absently blowing her breath on the window, obviously lost in some thought. Then, ‘Mommy? If its freezing, why don’t the tiny little biwds fweeze?’ Mom and I looked at each other and said, ‘Well, we give them food, but they obviously have other ways to stay warm. We’ll find out and report back.’ So, with those tiny bodies… How do they not wake up frozen to death?”
As chair of the Wintering Wildlife Subcommittee of the Reecer Creek Rod, Gun, Working Dog and Outdoor Think Tank Benevolent Association, I was duty-bound to respond. “Well, of course, it starts with enough food,” I said. “They have to eat regularly or they die. And the ideal food will vary from species to species, so we include oily seeds and suet for those that need oil as a good burning fuel for their bodies, keeping their metabolic rates up.”
I reached for my copy of “The Birder’s Handbook,” by Ehrlich, Dobkin and Wheye, and pulled up Bird Whisperer of Paradise Deborah Essman’s list of our most common small birds. I offered a couple bird/nature guides to help his kids identify the birds at their feeder (Bird Whisperer’s list includes the English – house – sparrow, house finch and gold finch, black-capped chickadee, dark-eyed junco and redpoll), and showed him how to find, in the Handbook or online, the food and life needs of each bird that he and his family might identify.
Obviously, if a bird or animal’s metabolism stops, it dies, and different birds have different metabolic rates. Smaller birds have proportionately greater surface area in relation to their body mass than do larger birds, so little birds lose their body heat faster in the cold. Since they all maintain similar body temperatures, small birds have higher rates of metabolism than big ones and eat proportionately more food. Hummingbirds, for example, have the highest rate of metabolism of any animal – about a dozen times that of a pigeon and a hundred times that of an elephant, so they must consume their weight in nectar daily. (It is believed that no warm-blooded animal could survive if it was smaller than a hummer, since it could not eat fast enough to stay alive – but some argue for the shrew.)
Each bird has its own needs and many have special adaptations. The redpolls, for example, have a partially bi-lobed pocket about midway down their necks, where they can store seeds for when needed. The little chickadees are often seen “caching” seeds in some crevice or other hiding spot. Most, however, just need handy food.
Then there are all those feathers holding in the heat generated from metabolizing that food. We have all observed birds sitting “fluffed up” in some protected spot (the Hucklings called them “feather balls”). This erection of feathers traps air in innumerable tiny pockets, providing excellent insulation (think featherbeds). A bird’s skin temperature may be 75 or more degrees warmer than the air less than an inch away. You have probably noticed that juncos, finches and sparrows foraging in cold weather frequently drop down, covering their legs and feet with their breast feathers while pausing in their food search, thus minimizing heat loss from featherless parts of their bodies.
Dark objects commonly absorb more sunlight than lighter objects, and it has been assumed that dark-feathered birds absorb more energy that light-colored birds. It turns out that there are several other factors at work, and a great deal depends on such things as wind speed and whether feathers are sleeked (laid back) or erected. In fact, in cold temperatures and moderate winds, erect white plumage gains heat better (and is more resistant to heat loss) than dark plumage.
To help birds keep feathers clean – thus best able to erect and insulate – provide water for baths, keeping it heated if possible. Provide areas near your feeders where vegetation is dense enough to still the wind (and protect from predators), and put up birdhouses or house-like structures where your little feathered friends can cuddle up next to other to minimize metabolic outputs.
It takes food and feathers to get these critters (from whom we derive so much pleasure) through the cold season. A thoughtful feeding area helps them maximize the use of each.
Homey, your kids will love helping to plan feeding areas and choose bird food. Happy cold weather bird watching.
