Why do birds look fat when it’s cold?

It’s Winter time here in the UK and the temperature outside has been close to freezing for several days. We’ve had a flurry of snow, a little ice and plenty of frosty mornings. Sometimes, the water in the bird bath is frozen, so I melt it with warm water from the tap and leave out some bread and fruit for the birds to eat if they visit our garden.

My 7-year-old has noticed the birds plumping themselves up as they sit in the bushes and hop around the bird-table. “Why do they make themselves look fat?” she wondered. Let’s find out…!

Birds, like people and other animals, like to keep themselves warm when the weather gets colder. But they can’t just put on a jumper or a coat, like we do, so they have to find another way to stay warm. Their feathers provide some warmth and help to protect their skin but in Winter they need a little extra something – and that something is air. Birds will fluff up their feathers to trap air between their feathers. Air is good at holding onto heat, so it acts as an insulator keeping the birds toasty warm.

Air is also good at keeping us warm, which is why we trap it inside the stuffing of our pillows and duvets. That’s also why knitted blankets or jumpers often have holes in their pattern, to trap air and hold onto the heat from your body.

But there are other reasons why birds sometimes fluff up their feathers:

• if they are unwell
• to scare off a predator or bigger bird
• to make themselves more attractive to a mate

If you’re interested in birds, why not try a spot of bird-watching? It’s a great activity for this time of year because you can do it from indoors! Here’s a handy guide of things to look out for. Happy twitching!