Other Birds - Sounds Wild
Bird Eyes


Download Episode: Bird Eyes (MP3 file 3,524 kB)


Bird eyes

A chilly but calm winter day finds me at the beach watching seaducks. Winter in Southeast Alaska is a great time to see overwintering waterfowl and seabirds. Today, mixed flocks of Barrows and common Goldeneye are rafted up just offshore. These ducks are aptly named, they really do have goldeneyes. I see loons as well, with their bright red eyes. Bird eyes can be striking colors, but they are even more amazing in their functionality.

Bird eyes are incredibly well adapted and varied, and their vision can be very different from ours. We have three different types of color receptor cells or cones in our retinas that detect red, blue, and green light, but birds have an extra one that allows them to see into the ultraviolet end of the spectrum. They also have oil in their cone cells which may enable them to detect even more variation in color - useful in finding mates and food. Birds can detect ultraviolet light reflecting off urine trails of rodents – which helps them track their prey; they can distinguish fruits and stages of ripeness, and can see greater color variations and patterns in other birds.

Birds vision is critical. They fly, dive, and swim – hitting breakneck speeds, swooping through narrow branches, plunging underwater, swimming through raging rivers, and pursuing insects and other birds from far away and high above. Their eyes have built in goggles and binoculars, they can see underwater, detect colors unknown to us, and they can see the very magnetic fields of the Earth.