Why do birds have a third eyelid?

What Crafty Clover says in this video

Intro

Hi there, curious minds! I'm Crafty Clover! Let's discover something amazing. Why do birds have a third eyelid?

The Big Idea

Birds have an extra eyelid! It slides across the eye sideways. Why do birds have a third eyelid?

A Sideways Blink

Step one: A Sideways Blink. A bird has an extra, thin eyelid called a nictitating membrane. It slides sideways across the eye, and it is clear or semi-clear, so the bird can keep watching.

Wipe and Protect

Step two: Wipe and Protect. The membrane wipes away dust and spreads moisture over the eye. It also protects the eye from wind, sand, and splashes.

Underwater Goggles

Step three: Underwater Goggles. Some diving birds use it like a built-in pair of swimming goggles. It shields their eyes while they chase food underwater.

A Closer Look

Let's take a closer look! Stays protected. Quick blink. Spread around. For diving.

Quick Facts

Quick facts! Some sharks have a similar eyelid. Cats have a third eyelid too. The sideways blink is super fast. Birds can see through it.

Think Like a Scientist

Now, think like a scientist! Watch a pet bird or a bird video. Look closely at the eye. Try to spot the quick sideways blink. Slow the video down if you can. How many blinks did you catch?

Outro

Birds have a thin, see-through third eyelid that slides sideways across the eye. It wipes away dust, spreads moisture, and protects against wind and sand, and diving birds use it like built-in goggles. Science is amazing! Keep wondering and keep exploring! Share what you learned with someone at home, and see what they think! Crafty Clover can be found on Amazon Books, Google Bookstore, and Apple Books. Available for purchase or download! Bye for now!