Skip to main content Skip to navigation
Home
Today's Show: Feathered Females in Charge
Wilson's Phalarope shouts orders
Listen In
  • Today's Show
  • Listen
    • Daily Shows
    • Threatened
    • Grouse
    • BirdNote Presents
    • How to Listen
  • Explore
    • Field Notes
    • Sights & Sounds
    • Birdwatching
    • Resources for Educators
  • How to Help Birds
    • At Home
    • In Your Community
    • Success Stories
  • About
    • The BirdNote Story
    • The Team
    • Partners
    • For Radio Stations
    • Funding
    • Contact Us
    • FAQs
    • Support BirdNote
  • Donate

Why Birds' Feet Don't Freeze

"Rete mirabile" - a wonderful net
Subscribe to the Podcast
Download
  • Share This:
  • Share to Facebook
  • Share to Twitter
  • Share to Email
Northern Flicker
© Pam Morris

Have you ever watched ducks walking around in freezing temperatures and wondered why their feet don't freeze? And how do birds, including this Northern Flicker, sit on metal perches with no problem? Birds' feet have a miraculous adaptation that keeps them from freezing. Rete mirabile — Latin for "wonderful net" — is a fine, netlike pattern of arteries that interweaves blood from a bird's heart with the veins carrying cold blood from its feet and legs. The system cools the blood so the little blood that goes down to the feet is already cold, so the birds don't lose much heat. The small amount that goes to the feet is likely just enough to keep the feet from freezing.

  • Full Transcript
  • Credits

BirdNote®
Why Birds' Feet Don’t Freeze
Written by Frances Wood

This is BirdNote!

[Mallards quacking]

Have you ever watched ducks walking around in freezing temperatures and wondered how they keep their feet from freezing? The ducks seem oblivious to the cold, even as they stand on ice-covered lakes and streams. Or perhaps you’ve been concerned that the tiny feet of songbirds will freeze to metal perches. [Winter song of Pacific Wren]

Unlike our feet, birds’ feet are little more than bone, sinew, and scale, with very few nerves. But it takes more than a lack of nerves to keep their feet from freezing. An amazing adaptation called rete mirabile is responsible. The arteries that transport blood into the legs lie in contact with the veins that return blood to the bird’s heart. The warm arteries heat the cooler veins. Because the veins also cool the arteries, the bird’s feet are closer to environmental temperature and thus don’t lose as much heat as they would if they were at body temperature.

[More song of songbird]

And those little songbirds’ feet?—don’t worry. Birds’ feet lack sweat glands and stay dry. So, there is no danger of them freezing to metal perches.

What was that called again? Rete mirabile.

For BirdNote, I'm Michael Stein.

###

Call of Mallard and the song of the Winter Wren provided by The Macaulay Library of Natural Sounds at the Cornell Lab of Ornithology, Ithaca, New York. Mallard recorded by A.A. Allen, Winter Wren by G.A. Keller.
BirdNote’s theme music was composed and played by Nancy Rumbel and John Kessler.
Producer: John Kessler
Executive Producer: Chris Peterson
© 2015 Tune In to Nature.org   December 2013/2017/2020  Narrator: Michael Stein

ID#121905reteKPLU  rete-01c
 

 

Frances Wood
Writer
Michael Stein
Narrator
Support More Shows Like This
Tagsornithology science

Related Resources

Learn more about rete mirabileNorthern Flicker - More at All About Birds

More About These Birds

Northern Flicker (Colaptes auratus)

Colaptes auratus

Mallard (Anas platyrhynchos)

Anas platyrhynchos

Sights & Sounds

Related Field Notes

August 25, 2017

American Wigeon, A Painting by Barry Kent MacKay

By Barry Kent MacKay
American Wigeon ... one of three species sharing the common name
March 23, 2017

Chandler Robbins, In Memoriam

By Rick Wright
Chandler Robbins, July 1

Birds connect us with the joy and wonder of nature. By telling vivid, sound-rich stories about birds and the challenges they face, BirdNote inspires listeners to care about the natural world – and take steps to protect it.

Support BirdNote

  • Daily Shows
  • Field Notes
  • BirdNote Presents
  • Sights & Sounds
  • About BirdNote
  • Contact BirdNote
Sign up for our newsletter!
  • BirdNote on Facebook
  • BirdNote on Twitter
  • BirdNote on Instagram

Copyright 2021. All rights reserved.

  • Privacy Policy