How Birds Stay Warm

It’s sleeting in the Upstate this afternoon and snow is forecast for evening, so I’ve filled my bird feeders to the brim.  Feeding birds in winter, especially when the weather is frigid, is important because burning calories is the best way for birds to create body warmth.  Providing high-calorie seed and suet is almost as good as supplying an electric blanket.

Left to right:  female Downy Woodpecker,  female House Finch,  three Goldfinches (one female and two males just beginning to show color), and a male House Finch (red face).

Left to right: female Downy Woodpecker, female House Finch, three Goldfinches (one female and two males just beginning to show color), and a male House Finch (red face).

Birds have other tricks for keeping warm too.  Their feathers have an oil coating that insulates and helps keep them dry.  Old feathers are molted in autumn, so new, thicker, and more numerous feathers are produced just before the coldest time of year.  And when the temperature drops, they fluff their feathers to add a layer of insulating air, just like a down jacket.

Evergreen conifers are the bird’s best plant friend in winter, sheltering them from predators, precipitation, and blistering winter winds, so they seek out these densely branched trees and shrubs.  Some evergreens also provide food in the form of nuts, seeds, or berries.  A few of our natives, such as junipers and cedars, make a cozy bed & breakfast for both resident and migrating birds.

The toothpick-like legs of birds are covered in tiny scales, similar to our fingernails, which keep them from becoming frost-bitten.  The legs also have a unique circulatory system with arteries and veins lying side by side, so the blood returning to the body is heated by that being pumped to the bird’s feet.  When you see a bird hunched over its legs, you know it’s really frigid.

Left to right:  male House Finch, female Northern Cardinal, and two female Goldfinches.

Left to right: male House Finch, female Northern Cardinal, and two female Goldfinches.

Understandably, larger birds deal with cold better than smaller ones.  In fact, the smallest can lose as much as ten percent of their body weight overnight in bitter weather.  Birds can shiver like we do, using their flight muscles to stay warm.  And some, like chickadees, can slow their metabolism to conserve energy in a state called nocturnal hypothermia.  In this torpor, the heart rate is lowered and the body temperature drops 10 to 15 degrees, or even more.

Others, such as the Eastern Bluebird, will roost together in tree cavities or birdhouses to stay warm.  One winter, I was surprised to see 16 bluebirds enter a single bird box to coop together in a snowstorm.

Two female Downy Woodpeckers have a spat while a Tufted Titmouse visits the safflower feeder.

Two female Downy Woodpeckers have a spat while a Tufted Titmouse visits the safflower feeder.

Currently, my garden is home to a suet feeder and three seed feeders, one each filled with niger seed, black oil sunflower seed, and safflower seed.   The suet draws smaller woodpeckers, such as the Hairy and the Downy, plus the Carolina Wren.   The niger seed is a favorite of the Goldfinch, the black oil sunflower seed draws the Red-Bellied Woodpecker and the Nuthatch, and the safflower seed is eagerly sought by the Northern Cardinal, Tufted Titmouse, and Carolina Chickadee.

19 thoughts on “How Birds Stay Warm

  1. johnvic8

    I’m not very happy with your weather forecast of what’s coming our way, but I am delighted with your post. We too are seeing a lot of activity at the feeders. Stay warm.

    Reply
  2. Evelyn JW

    The suet recipe, that you gave a few years ago, is my bird’s favorite, in fact, they will not eat a bought one. All the birds eat from it,(I put a perch on it) the doves have tried, but cannot figure it out, so they continue to watch the other birds eat while craning their necks to think about it. The ground birds gather underneath to pick up suet bits that fall.

    Reply
  3. Julie

    A lovely post Marian, we have a mixed seed, niger seed, peanut and a couple of suet feeders. The suet is bought but comes with crushed insects and dried meal worms in, we have found that to be very popular. Its National bird box week here too aimed at encouraging folk to put up more nest boxes. I hope you and your birds keep warm.

    Reply
    1. Marian St.Clair Post author

      Julie–Sounds like great suet you have, I’ve never seen anything like it here. I might try a bird box this year, but worry because we have so many snakes. Perhaps the front garden where there is more activity would be a good option.

      Reply
  4. Christina

    Great post Marion, I don’t have feeders in the garden but now that the garden is more established and there are more seeds and berries I have seen a lot more birds visiting the garden. There are more hedges and trees for them to nest and roost in too.

    Reply
  5. Chloris

    What a fascinating post Marian. I never knew this about birds’ legs. Here in the UK little wrens ((Troglodyte troglodyte) roost together in groups of 6 , 8 or even more when it is very cold. I think tits tend to roost separately.

    Reply
  6. Barbara Wilder

    I’ve been fascinated with bird activity that occurs prior to the arrival of the cold. Several hours before the sleet began to fall, the birds began to stage themselves in the redbud tree located near my feeders. A multitude of cardinals filled the branches as if the tree was in bloom. They seemed so polite as they waited their turn to approach the feeders. And then the red-bellied woodpecker showed up and demanded to be the big man on campus! .He took no care of all the seeds he didn’t like and sent them flying to the ground so the towhees had enough to survive. Time to refill the feeders!

    Reply
  7. Darlene Roehl

    See your shepherd’s hook but can’t tell how tall it is & therefore how you keep the pesky squirrels off of it. We’ve had a real fight this winter, finally hanging the suet cage from a house eave. Mr. Squirrel hangs by his back feet & pulls the chain up “hand over hand” so he can lay it out on the roof & feast!

    Reply
    1. Marian St.Clair Post author

      Darlene–There is a torpedo-shaped squirrel baffle, open at the bottom like a bell, just below the feeders. I’ll put up a full photo soon, so you can see the whole outfit. I bought it at one of the birding places, so it wasn’t cheap, but (knock on wood) it has worked so far.

      Reply

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