Fat for Warmth

Most birds survive our brutal winter weather. But how?

On bitterly windy days, birds tuck in behind evergreen foliage, buildings, or whatever other windbreak they find. Even out of the wind, though, it’s no tropical paradise.

Many birds increase their number of feathers in fall, shedding some come spring. But the minimal increase still won’t fully insulate their tiny bodies.
At night, birds face the greatest challenges. Some, like Carolina or Black-capped Chickadees, lower their nighttime body temperature to conserve energy. But like all birds, they need a secure roost, out of the wind, protected from predators. 

What ultimately gets them through? One word: fat. If they’ve had enough fat calories during the day to last them through the night, if they can find enough fat calories at dawn to replenish their depleted reserves, and if they can find enough fat calories to gain enough reserves to last through the next night, they’ll survive another day.

And where do they find all this fat? In seeds, dormant bugs, insect eggs and larvae—and lots of them. In summer, chickadees, for instance, need the equivalent of 150 seeds a day to stay alive. In winter, however, those same birds need 250 to 300 seeds a day—60 percent of their body weight—to survive severely cold nights.

For birds, winter survival is a frantic daylight-to-dawn search-and-feed operation—every minute, every day. Their search includes, but is not limited to, your feeders. So you’ll help most if you’re offering high-fat foods, the highest being black-oil sunflower seed (especially sunflower hearts), peanut kernels, and pure suet.

To follow yesteryear’s habit of throwing out stale bread and cookies, popcorn, and other human prepared foodstuffs probably hurts birds more than helps them. They gobble up the offerings, of course, and fill their tummies. But the food value—the fat content—is absent. Worse yet, they’re getting refined ingredients, salt, sugar, and additives that, to their tiny bodies, is not at all helpful.