Question:
When birds fly in the rain, why doesn't it hurt their eyes?
Replies:
Birds have a special third eyelid, called the nictitating membrane, under
their regular eyelids. It is transparent in most birds, and is drawn across
the eye to moisten or clean it. A quote repeated in the Audubon Encyclopedia
of Birds: "...many ornithologists believe the nictitans is held over the eye
most or all of the time that a bird is in the air - the forerunner of the
motorist's goggles."
NEWTON is an electronic community for Science, Math, and Computer Science K-12 Educators, sponsored and operated by Argonne National Laboratory's Educational Programs, Andrew Skipor, Ph.D., Head of Educational Programs.