How Do Birds Stay Warm In Winter?

When Winter weather sets in, and you’re sitting indoors looking out at a winter landscape that could be on a Christmas card, have you ever wondered how do birds stay warm in Winter? The main insulation birds have against the cold is their feathers which they puff up to trap air that warms and keeps them protected from the lower temperatures. Many birds grow extra feathers during the Autumn in preparation for the colder Winter months. 

How Do Birds Become Weather-Proof?

Apart from growing extra feathers and fluffing them up in order to keep warm, they also have a waterproofing coat of oil that covers their feathers which is produced in the preen gland. Plus their bare legs and feet are covered in scales to help prevent heat loss. Birds also have the ability to lower the flow of blood to their extremities to prevent heat loss.

To preserve heat even more, many birds will stand on one leg and tuck the other leg under their feathers. You can often see birds in this one-legged pose with their beaks tucked under the feathers near to their shoulders. In extremely cold conditions they crouch low, covering their legs with their feathers as well all in order to preserve heat.

They will have built up their fat reserves during Autumn, to provide extra insulation and energy to produce heat when the thermometer drops. When the sun shines during Winter months, you will often see birds with their backs turned to face it and their feathers raised to absorb as much heat from the sun as they can. When it’s really cold, birds shiver to help raise their metabolism to create more warmth.

The Ways Birds Prevent Heat Loss (Stay Warm) During Winter At A Glance

• Birds Puff Up Their Feathers
  This traps air that becomes warm due to body heat,  birds can retain around 90% of their regular body temperature by fluffing up their feathers.Often these feathers have been specifically grown just for Winter
• Their Top Feathers Are Waterproofed
  Birds waterproof their feathers using oil secreted from the preen gland
• They Have Scales On Their Legs
  These scales help to prevent heat loss
• They Stand On One Leg
  Allowing the concealed leg to warm up, and then swapping legs
• They Tuck Their Legs Under Their Wings
  By slumping or crouching their bodies, birds can cover their leg(s) with their wings
• They Tuck Their Beaks Under Their Wings
  This reduces heat loss even more
• Birds Take Shelter In Tree Stumps
  Anywhere they can shelter including tree stumps, hollows, eaves of houses, and barns
• Huddle Together
  They use their combined heat to keep warm with the outer ones swapping positions when they become too cold
• Shiver
  Birds shiver as a short-term measure to warm up
• Enter A State Of Torpor
  This is almost semi-hibernation, which lowers their respiratory rate, heart rate and metabolism which means they use less energy

Birds Of A Feather Flock Together

During Winter months you will often find many birds huddled close together to conserve and share heat with each other. During the night they go into a semi-meditative state known by scientists as torpor. Torpor is a condition birds can get into where they have lowered their metabolism, heart rate, respiration and sometimes body temperature, which is just above the state of hibernation.

 This is a good way for them to save energy, but can leave them vulnerable to predators. Which is why they usually only enter a state of torpor when they are gathered together in medium to large groups. This is because they can then take turns at being on watch out for danger.

Crows Spend Winter In Large Groups

During the Winter months crows gather in their thousands at night to keep warm. These large groups meet up each night only to separate every morning in search of food. These large roosts are not only used for keeping warm, they also share knowledge of areas to forage for food, and lessen the risk of predator attack.

Bird Size Matters 

During cold Winters nights small birds can lose more than 10% of their body weight due to heat loss and reheating their bodies. In some cases more than 20% of their body weight can be lost in extremely cold conditions. So it’s really important that they not only increase food intake during the day but also find somewhere warm at night. Birds either huddle together or find disused bird boxes, small gaps under the eaves of houses, or even tree trunks with holes.

The north wind doth blow,

And we shall have snow,

And what will the robin do then, Poor thing?

He’ll sit in a barn,

And keep himself warm,

And hide his head under his wing, Poor thing!

The north wind doth blow,

And we shall have snow,

And what will the swallow do then, Poor thing?

Oh, do you not know

That he’s off long ago,

To a country where he will find spring, Poor thing!

This old children’s poem (which does have more verses relating to other wildlife) is quite an accurate account of how robins and swallows deal with harsh Winter conditions. The robin trying to conserve energy by tucking his beak under his wing, and the swallow flying off to warmer climes until Spring returns.

Territorial Differences Put Aside For Winter

Many birds huddle together during cold Winter nights to conserve heat and energy. It’s surprising just how many varieties will adopt this practise when you consider how territorial they can be during the warmer months of Spring and Summer. Birds like wrens that are so territorial that they don’t tolerate any birds getting near, no species can dare enter the wren’s domain.

Most birds will deter members of their own species but usually other species are accepted but that’s not the case with wrens. Wrens will even attack humans who wander too close to their nesting sites and any predators will not have an easy time with a wren. That is until Winter, then wrens will not only huddle together for warmth with birds of their own species, but they will even huddle with other birds too.

How Do Ducks Stop Their Feet From Freezing?

Ducks and swans need to enter the water daily to find food. Summer or Winter they still need to eat, so they sometimes need to enter icy water to find food. How do they stop they’re feet from freezing? They have a counter flow system of heat exchange in their legs with veins and arteries close together. So that as warm blood leaves the body it warms up the cold blood that’s re-entering the body. 

When on dry land, many waterfowl employ the trick of standing on one leg, while others sit down in one spot to conserve heat loss.

What Garden Birds Can You Expect To See In Winter?

Bird types drop off here in the UK during Winter, with many birds migrating to warmer climes and not returning until Springtime. Some of the garden birds you can expect to see during Winter include;

• Starlings
• Pigeons
• Sparrows
• Goldfinches
• Long-Tailed Tits
• Robins
• Blackbirds

How Can We Help Birds Keep Warm In Winter?

The main thing birds need to survive Summer and Winter is food and water. During Winter months it is important to provide birds with suitable foods to help them maintain their body temperature. Foods like;

• Peanuts (Unsalted)
• Peanut Butter
• Sunflower Seeds
• Suet
• Fat Balls
• Niger Seeds
• Apples (De-Seeded)
• Pears (De-Seeded)
• Cheese (Crumbled)
• Bread Crumbs (In Small Quantities)

Always remember to clear any uneaten food away before evening to prevent spoiling or rodents. In the long term, try growing bird friendly plants to encourage them to visit your garden. Include some berry and seed producing plants and some that attract insects.

Providing fresh water for the birds is also important during Winter months, a small birdbath will attract many birds as long as you don’t allow it to freeze. If it does freeze, only defrost using hot or warm water, not de-icer or salt. Both de-icer and salt are poisonous to birds.

Frequently Asked Questions