how do birds feet not freeze

When you see waterbirds standing around in cold water, or wandering across the ice, you might wonder why they don’t get frostbite in their feet. So how do ducks, geese and swans cope with the cold weather in the winter?

If you’ve ever visited a wetland in winter, you’ll know that it’s far from a quiet time of year. Waders whirling in flocks, thousands of geese and swans arriving from the freezing Arctic and raptors swooping in with deadly energy to send the saltmarsh into chaos.

Although filled with food, wetlands can be exposed places in winter for waterbirds like ducks, geese and swans. Despite our warming planet, some places are still extremely cold with wintery conditions that might last as late as April. So how are birds adapted for life out on wet and windy wetlands?

Another interesting myth about ducks is that their quack does not produce an echo. Ridiculous as this might seem, it has actually been scientifically disproven in the lab.

Ducks love water – but not rain

Wetland birds that migrate frequently push themselves to the absolute limits of endurance during the winter, even though they are adapted for life in the cold. For this reason, it’s critical to preserve the wetlands that birds are familiar with and depend on.

A number of wetlands serve as “bird service stations” or staging posts for a variety of birds, allowing them to pause, eat, and rest before continuing on their journey. They frequently impart to the next generation the knowledge of these havens.

These staging areas are vital to their survival, and the loss of even one of these priceless locations could severely hinder the migratory birds’ ability to migrate. You might be able to find another service station nearby, but that would require more energy that you don’t have, and it might not even have the right kind of fuel when you get there. Imagine arriving at a service station with only a few liters of petrol left in your car only to find that it was gone.

With such narrow margins, we cannot overestimate the importance of keeping our wetlands safe and in a healthy state. According to a 2017 BTO report on the state of the UK’s birds, ‘the importance of these sites (protected areas) has been clear during particularly cold winters (eg 2009/10 and 2010/11).

Wetlands are important migratory bird service stations in winter

Birds’ feet have a miraculous adaptation that keeps them from freezing. Have you ever watched ducks walking around in freezing temperatures and wondered why their feet don’t freeze? How do birds, like this Northern Flicker, sit on metal perches with no problem? Rete mirabile, which translates to “wonderful net” in Latin, is a delicate, net-like pattern of arteries that connects a bird’s heart blood with the veins that carry its cold blood in its legs and feet. The blood is cooled by the system, preventing much heat loss in the birds by making the blood that does travel to the feet already cold. It’s likely that the tiny amount applied to the feet is sufficient to prevent them from freezing.

Here’s BirdNote! [Mallards quacking] Ever notice how ducks walk around in subfreezing weather, seemingly oblivious to the cold, even as they stand on ice-covered lakes and streams? I’ve always wondered how they keep their feet from freezing. Or maybe you’ve been worried that songbirds’ tiny feet will freeze to their metal perches. [Pacific Wren winter song] Unlike human feet, the feet of birds are primarily made of bone, sinew, and scale, with very few nerves. But to prevent their feet from freezing, it takes more than just a lack of courage. An amazing adaptation called rete mirabile is responsible. The veins that return blood to the bird’s heart are in contact with the arteries that supply blood to the legs. The warm arteries heat the cooler veins. The bird’s feet are closer to ambient temperature and thus don’t lose as much heat as they would if they were at body temperature because the veins also cool the arteries.

### 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. Nancy Rumbel and John Kessler composed and performed the theme music for BirdNote. © 2015 Tune In to Nature Executive Producer: Chris Peterson, Producer: John Kessler org December 2013/2017/2020 / November 2022 Narrator: Michael Stein.

And those little songbirds’ feet?—don’t worry. Birds’ feet lack sweat glands and stay dry. Therefore, they won’t be in danger of freezing to metal perches. What was that called again? Rete mirabile.

Why birds’ feet don’t freeze in cold water

You might wonder why waterbirds avoid frostbite when you see them floating in cold water or frolicking on the ice. Their ability to regulate the temperature differential between their feet and the ice is a result of a thermoregulatory adaptation.

A counter-current heat exchange system is found in the feet of many waterbirds. This means that as blood is pumped around, warm arterial blood and cold blood pass close to one another, lowering the temperature of their feet while maintaining their range of motion. As a result, there is less chance of frostbite developing because the temperature of the ice and the birds’ feet is closer. This is because the risk of frostbite increases with the size of the difference between the two surfaces (the ice and the feet). The greater the difference, the more heat is lost from the hot object (the foot).

As arterial blood is pumped, warm and cold blood pass near to one another.

In general, geese prefer to be on land, and at night, they can be observed congregating on the ground. They frequently leave little goose-shaped patches—complete with goose poop—to indicate where they have been after a heavy frost.

We install unique bubbling features at WWT reserves to keep our ponds free of ice and duck-safe.

Still confused? Watch our aviculture expert Phoebe explain the process.

One of a bird’s distinguishing characteristics is its feathers, which are not only essential for flight but also highly insulating. As the earliest birds evolved to become warm-blooded, feathers actually evolved first for insulation before flight. The preen gland, found at the base of the tail, is responsible for producing the oil that the bird needs to rub all over its body in order to waterproof its feathers. In order to aid with waterproofing, herons and egrets even have unique feathers called “powder down” that break off into particles akin to talcum powder.

Birds “fluffing” their incredibly dense feathers to trap air can be seen if you look closely; it’s like having a down coat attached to your body. The incredible insulating properties of eider duck nest feathers have made them highly valued for many years as bedding and coat materials.

A wood pigeon fluffs its feathers to stay warm.

FAQ

How do birds not freeze in the winter?

Whether fat, fur or feathers, insulation matters for most cold-weather animals. All cold-climate birds pack on body weight in the late summer and fall in anticipation of the long, cold winter, but feathers also play an important role. All birds stay warm by trapping pockets of air around their bodies.

What adaptation prevents bird feet from freezing?

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.

Do birds feel pain in their feet?

Bird legs and feet have very few pain receptors and little fluid. The surface is dry and scaly, with no moisture, which means they don’t have to worry about their feet freezing and getting stuck to metal perches, even on a cold and snowy day.

Why don’t swans feet get cold?

Thanks to a network of arteries—called rete mirabile or “wonderful net”—a bird’s heart is wired to its feet in such a way that by the time the tiny amount of blood gets down there, it’s cooled. And when blood flows back up, it’s warm.