Puff, Fluff, and Feather Stuff

Birds’ Artful Way of Keeping Warm and Surviving Winter’s Coldest Days

Reading Time: 2 minutes

On cold winter days, did you ever notice your backyard birds look fluffier?

The birds look like they grow 3 sizes bigger. I same way I feel when I eat too much bread.

After a super fluffy male American Goldfinch caught my eye, I decided to investigate the mystery behind the fluffiness.

Role of Bird’s Feathers

A bird’s feathers are quite magical.

Feathers weigh on average just .0082 grams, yet they’re strong and durable enough to provide their wearer with exceptional insulating capabilities.

On average, most bird species feathers’ are usually two to three times heavier than the bird’s entire skeletal system.

So even though feathers are incredibly lightweight, if you put all of a bird’s feathers together, they can get heavy.

Fluffy American Goldfinch keeping warm during a snow storm in New York

Birds Look Fluffier

When you see birds looking fluffier, that’s because they can contour their feathers.

Birds flatten or fluff up their feathers to create more airspace between them as a way to regulate temperature.

So the hotter a bird gets, the flatter its feathers become without airspace.

And the colder the bird, the fluffier they become as they puff up and trap air that acts as additional insulation between their feathers.

So does the fluffiness mean birds have more feathers in winter?

More Feathers for Winter

Stan Tekiela, an author, naturalist, and wildlife photographer with a fabulous column called Nature Smart on The Drummer, confirms my suspicion. 

An American Goldfinch or Black-capped Chickadee is covered with approximately 1,100 feathers during summer, but their feathers increase to over 2,500 in winter. 

If you look closely at the bird, it doesn’t look like it has many more feathers because the outer contour feathers overlap each other and lay flat. 

A fluffy Black-capped Chickadee on a cold winter’s day

But these songbirds add more small, fluffy down feathers in preparation for winter, which occur under the outer feathers, where you can’t see them.

So the next time you’re watching your backyard birds, and they look fluffier to you, it’s because they are.

Take a few pictures and compare them to ones from the spring, and they’ll look like two different birds.

Just be sure to list them as only one species on your bird list. You don’t want to puff the numbers.


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