How do crows stay warm in the winter?

Snow ‘stache, originally uploaded by zpeedyz.

How DO crows (and other birds) stay warm in the winter?

Crows have a higher body temperature than humans due to their significantly higher metabolism. While the average human’s body temperature is 98.6ºF (37ºC), the average bird’s body temperature is appriximately 105ºF (40ºC). To maintain this higher temperature birds have a few physical helpers as well as some behavioral helpers.

Physical helpers:

Birds have unique scales that cover their feet and legs which minimize heat loss.

Birds have an extraordinary circulatory system in their legs to help them cope with cold temperatures. Warm arterial blood from the birds interior that is on its way to the bird’s feet passes through a network of small passages that runs along side the cold returning venous blood from the feet. The network of vessels acts like a radiator and exchanges the heat from the out-going arterial blood to the cold venous blood. This system insures that no heat is lost and the bird’s feet receive a constant supply of life sustaining blood. That’s also why ducks can swim in freezing water and not get cold.1

Birds have feathers coated in oil which is important for waterpoofing / snowproofing. Birds often grow more feathers during late fall to give them extra protection for winter. They can also fluff up their feathers during particularly colder days and nights which can reduce the amount of heat loss by up to 30%!!!

Birds have a different kind of fat than humans. Birds have white fat which is a high-energy fuel used to power the birds warming process, shivering. Shivering produces heat five times their normal basal rate and can maintain a normal body temperature for six to eigh hours at temperatures minus 70ºF.2 Since this fat is so important to our feathered friends, birds will often try to store extra fat for winter.

Crows often go into a state called torpor where they lie on the ground with their bills half-open when sunning themselves, looking to all the world as if they are about to succumb to some terrible malady.3 Torpor is a state of unconsciousness where the bird is inactive and their core temperature drops approximately 10-12 degrees, respiration and heart rate drop and the bird’s body then needs less energy, thus saving approximately 20% of the energy which is then used to maintain body temperature.

Behavioral Adaptations

Birds use some particular behavior to conserve heat as well:

Tucking: When birds stand on one leg or crouch down covering their legs with its feathers. Birds can also tuck their bills into their shoulders as well.

Fluffing: Birds will fluff out their feathers to create air pockets for additional insulation in cold temperatures.4

Shivering: As I mentioned above, shivering is an important behavior for birds. Birds will shiver to raise their metabolic rate and generate more body heat as a short term solution to extreme cold. While shivering does require more calories, it is an effective way to stay warm.5

Sunning: On sunny winter days, many birds will take advantage of solar heat by turning their backs to the sun (therefore exposing the largest surface of their bodies to the heat) and raising their feathers slightly. This allows the sun to heat the skin and feathers more efficiently. Wings may also be drooped or spread while sunning, and the tail may be spread as well.6

Roosting: Crows roost, as many birds do, gathering in large flocks at night and crowd together in a small, tight space so they can share body heat. You can often see thousands of crows roosting together, and boy what a site that is for crow lovers!

Want to help keep crows warm in the winter?

  • Put out winter bird foods such as suet, the bird peanut butter, seeds and other bird foods high in fat. Keep your feeders full, check daily.
  • Put out fresh water daily. This will save them the energy of trying to find water.
  • Build or buy crow birdhouses and roost boxes.
  • Plant trees common for crows to roost in. Crows usually choose evergreen and deciduous trees. (To find a crow roost, watch for birds at sundown and follow them.)
  1. http://www.stantekiela.com/articles.php?articleID=129 []
  2. http://www.stantekiela.com/articles.php?articleID=129 []
  3. Lyanda Lynn Haupt, Crow Planet: Essential Wisdom from the Urban Wilderness []
  4. http://birding.about.com/od/birdingbasics/a/howbirdskeepwarm.htm []
  5. http://birding.about.com/od/birdingbasics/a/howbirdskeepwarm.htm []
  6. http://birding.about.com/od/birdingbasics/a/howbirdskeepwarm.htm []

13 thoughts on “How do crows stay warm in the winter?

  • Feeding the birds is a past time for some people. While you take a stroll with the kids or alone at the park, you may find it interesting to feed the birds. For some people feeding birds is a passion. Bird watchers are not only best at recognizing and naming birds, but also at the knowledge of bird food. Peanuts are most commonly used as bird food as it comes handy in the home kitchens.’

    Current short article from our new web blog
    <'http://www.caramoan.co/caramoan-island/

  • we have a crow born with a birth defect who can’t fly, we let him outside everyday and I was worried he might get too cold, I saw him shiver today but he didn’t want to come back in yet, he comes in the house at dusk, your explanation of how crows keep warm was helpful, thank you.

  • I am happy I could help. =) And good for you for taking care of that poor crow.

  • I feed my crows evèy day I love all types of birds but particial to crows. I love all animals.

  • This was fascinating. I was researching if a crow could survive sub zero temperatures (yes), and the altitude of a crow’s flight for a metaphor in a book I am writing. I didn’t expect it to be so interesting. Thanks.

  • Hi is your site still active?

  • Hi! I have a young crow (about 8 months old) so this is his first winter. He has a deformed foot so after I found him in my back yard this spring and after talking to some experts, I decided to keep him since most people thought he wouldn’t be able to survive on his own. He lives in the biggest dog crate I could find, on a closed porch that has no heating and lot of (closed) windows. Even when it’s really cold outside, it never freezes there (we keep our plants there during the winter). Should I worry about him getting cold? Especially since he adores water and bathing, even now when it’s starting to get rather cold, especially during the night (I am from Croatia, Europe). He doesn’t seem to be cold, but this is my first crow so I’m quite inexperienced and I obsess over him a bit too much 🙂
    Do I need to go and get him a heater? A sweater? Something else? 😀
    Thank you for any help you might provide!

  • I raised a jackdaw from a chic indoors, she became a pet that was six month ago.Unfortunately she escaped on the coldest day of winter and she had not come home I was worried she would not survive the cold but reading your article has perked me up thank you

  • How lovely of you to raise that chick! I do hope she will return to visit you someday! That would be such a nice surprise! I do hope she is well. I am sure she is, thanks to you!

  • Birds live outdoors naturally, so I imagine he is okay. However, make sure he has access to nesting materials…natural twigs and stuff that he can make into a makeshift nest/bed. Also, make sure he has access to water at all times. They use their feathers as a natural insulation to keep warm. A sweater would be funny! I wonder if he would let you put a sweater on him. That made me smile. =) I hope this helps…again, nesting materials and fresh water every day.

  • Yes, we are still active. We just take breaks every now and again. We do this for fun, not profit.

  • You are most welcome, Cheryl! Thanks for stopping by. By the way, what is your book titled and when will it be released?

  • YAYYYY for crow lovers! It is nice to know there are so many of us…and that ones like you help to take care of them! =) Thanks for writing!

Leave a Reply

Your email address will not be published. Required fields are marked *