Published in the Pacific American Singer newsletter, volume 6, number 2, April 1999.
Nope. They may see more than we do, at least in daylight! Thebirds' eyes, like ours, have two types of sense receptors: rods andcones. Rods are good for contrast, and work well in dim light. Nightpredator birds like owls have more of those than we do. Cones aregood for color discrimination. Canaries probably have more of thesethan we do. " ... the diversity of visual pigments found in birds'eyes, and the presence of an array of brightly colored oil dropletsinside the cones, suggest that avian color perception may surpass ourown." ¹
Human color blindness is usually the result of weak cones. In hisbook, "Island of the Colorblind," Oliver Sacks talks about a group ofpeople with total colorblindness. They have NO cones. They do not seeany color, and their eyes cannot tolerate sunlight.
I haven't found much research on canary eyes, but there is some onbirds in general.
Do you remember your rainbow colors? The visible spectrum is RoyG. Biv: Red, orange, yellow, Green, Blue, indigo, and violet. We knowthat there is an infra-red at one end of this visible spectrum & anultra-violet at the other, but our eyes can't see them.
As it turns out, hummingbirds can see ultraviolet (UV) light,making bright patterns on some nectar plants. They see it on daisies,for example, where we see plain white petals. I've heard that if youhold a daisy close to your eye in sunlight, and look flat across thesurface, you can see the faint glow of these patterns. "Black light"can give us an idea of what UV looks like.
Pigeons can see UV, too. They can also see polarized light. Theonly way we can see polarized light is by reflection. Sometimes, youcan see a cloud in the sky in a stream, but that cloud is not visiblewhen you look directly into the sky. In her book, "Pilgrim at TinkersCreek," Annie Dillard has a delightful section about this.
Because the lead in window glass blocks the UV light, the worldoutdoors must look quite different to them than the world indoors,perhaps the way things change for us when we put our sunglasses on?
UV light is what birds' and people's bodies use to manufactureVitamin D. Breeders feed Vitamin D to birds behind glass, out ofdirect sun, usually in wheat germ or cod-liver oil. Most of usbelieve that a full spectrum bulb will give our birds UV, but somesay that it isn't very effective. They point out that the bulb itselfis made of light-blocking glass!
It is possible that your canary can see more than you, except inthe night. Maybe they prefer a certain seed or leaf or pellet overall others is because of a beauty we can't even know? And maybe theyfly into a panic at night because of something we can't perceive?
¹ Paul Ehrlich, David Dobkin, and Darryl Wheye, The Birder'sHandbook, Simon & Schuster, 1988
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