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! The birds' eyes, like ours, have two types of sense receptors: rods and cones. Rods are good for contrast, and work well in dim light. Night predator birds like owls have more of those than we do. Cones are good for color discrimination. Canaries probably have more of these than we do. " ... the diversity of visual pigments found in birds' eyes, and the presence of an array of brightly colored oil droplets inside the cones, suggest that avian color perception may surpass our own." ¹
Human color blindness is usually the result of weak cones. In his book, "Island of the Colorblind," Oliver Sacks talks about a group of people with total colorblindness. They have NO cones. They do not see any color, and their eyes cannot tolerate sunlight.
I haven't found much research on canary eyes, but there is some on birds in general.
Do you remember your rainbow colors? The visible spectrum is Roy G. Biv: Red, orange, yellow, Green, Blue, indigo, and violet. We know that there is an infra-red at one end of this visible spectrum & an ultra-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 you hold a daisy close to your eye in sunlight, and look flat across the surface, 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. The only way we can see polarized light is by reflection. Sometimes, you can see a cloud in the sky in a stream, but that cloud is not visible when you look directly into the sky. In her book, "Pilgrim at Tinkers Creek," Annie Dillard has a delightful section about this.
Because the lead in window glass blocks the UV light, the world outdoors 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 manufacture Vitamin D. Breeders feed Vitamin D to birds behind glass, out of direct sun, usually in wheat germ or cod-liver oil. Most of us believe that a full spectrum bulb will give our birds UV, but some say that it isn't very effective. They point out that the bulb itself is made of light-blocking glass!
It is possible that your canary can see more than you, except in the night. Maybe they prefer a certain seed or leaf or pellet over all others is because of a beauty we can't even know? And maybe they fly into a panic at night because of something we can't perceive?
¹ Paul Ehrlich, David Dobkin, and Darryl Wheye, The Birder's Handbook, Simon & Schuster, 1988
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