Birds rely on their excellent vision to find, track and capture prey, choose a mate, and navigate while flying. They’ve evolved some unique adaptations to help.
The eye sockets of most birds is fixed, but some species can move each eye independently or focus on different tasks. Most have fixed eye sockets which can protect them from impact (think woodpeckers) but also requires the bird to swivel its head to change its gaze (think owls, like in this video).
They also carry a goggle-like eye cover, the nictitating membrane, which helps lubricate and protect the eye during flight or when diving into water. If you’ve ever been on a rollercoaster or opened your eyes underwater, you understand how having goggles could protect your eyes and improve your vision.
Avian retinas also contain four types of visual cells (mammals have three) plus each has a colored oil droplet to allow birds a great capacity to distinguish colors, including those in the ultraviolet range. And another cool thing... new research shows that biofluorescence is widespread among birds-of-paradise.