Sunday, April 25, 2010

How do Birds See to Fly in the Rain?

When birds fly in the rain- are their eyes open? Do they have a “rain shield” over the eyeball? It is raining here today, and the birds have been busy at the feeder, so my inquiring mind came up with that wondering. Bill K

Oooh, good question. Seed eating birds don’t depend on birdfeeders to survive and experts estimate that only 10-20 percent of their diet comes from feeders. But boy as you noticed, they do appreciate a known source of food in bad weather. They can visit your feeder, fill up and then go find some shelter to wait out the storm. It takes a lot more energy to fly in rainy conditions.

Besides upper and lower eyelids, birds also have a third eyelid called a nictitating membrane which sweeps sideways across the eye. Birds can blink repeatedly with the nictitating membrane to clean the eye’s surface and spread moisture across the eye.

And yes they do draw this “rain shield” or a translucent membrane across to protect their eyes from rain.

It can also help prevent the eye from drying out when migrating long distances and hold woodpeckers eyes in place and protect them from flying debris as they peck a tree. Or in some aquatic birds like the Hooded Merganser the nictitating membrane is clear and acts like a pair of goggles to help the birds locate prey underwater.

I’m glad your feeders were full and ready for the birds during the bad weather. Thank you for the very interesting question.
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Wow Sarah- Thank you for this interesting answer. I appreciate your time. Bill K

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