This is bird note.

During a rainstorm, you're more likely to see birds perched and hunkered down than flying

around.

Most birds are mostly waterproof.

Their feathers, combined with oil from pre-glans, keep them pretty watertight.

So, why do birds avoid flying during rainstorms?

It's not just about getting wet.

It may have more to do with the air than the water.

Storms alter the medium in which flight takes place the air itself.

Rainstorms tend to occur when atmospheric pressure is low.

Air in a low pressure system is less dense, but it's dense air that gives birds the aerodynamic

lift they need to take wing.

Falling rain and high humidity also add lots of water molecules to the air.

That water takes up space in the air, making it even less dense.

So rather than fly, many birds perched and conserved energy during a storm.

They sit it out under the cover of a tree, or perched on a fence wire facing into the

wind, reducing their air resistance, and limiting the loss of precious body heat.

So when the storm passes, birds once again take to the skies.

For Bird Note, I'm Mary McCann.

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