It’s In Your Nature: All eyes on deer and owl
Hunters probably would have wanted me to include this information in an earlier column. I, and other hunters, have always assumed that the white-tailed deer is color blind.
Recent research has revealed that deer, as expected, have many more rods on their eye’s retina which collect light coming through the lens. In fact, they can collect 50 times the light that human eyes can. This allows them to be very active at night. But their eyes do have many cones which allows for color reception. Our eyes have many more cones than deer, but deer can see colors.
Deer don’t see longer wavelength colors like red and orange very well. But they do see the shorter wavelength colors like the blues of the spectrum. So, if you are a hunter, or someone dressing safely in hunting seasons, blaze orange is extremely visible to human eyes, but appears grayish to a deer.
However, don’t wear your blue outfit, that color range is easily detected. Remember your elementary science days and the colors of the spectrum. Red, orange, yellow, green, blue, indigo, violet. (ROY G BIV is how I remembered that.)
Also note, that deer eyes are mostly fixed in their sockets and aligned on the sides of their head. Their binocular vision is limited to about a 60-degree range compared to our 120-degree range. However, if they look directly at you or a predator, they then focus quickly.
Now how about a nocturnal predator - the owls. They have their retinas loaded with rods and can collect even more light than deer, and especially more than humans. In fact, they can gather about 100 times more light than us. They then have poor color vision having very few cones and are considered color blind. Owl’s eyes are fixed in their sockets but as you know they have the ability to swivel their heads nearly 180 degrees. They do have a great ability to see in low levels of light, but no, they are not blinded in daylight.
Hearing is maybe their best asset. Owls have facial discs, the concave feather arrangement on their heads, to better direct sounds to their ears. (Their ears, by the way, are not on the top of their heads, but on the sides at the edge of the facial discs. The feathers on the top of many owls’ heads are just tufts of feathers.
A barn owl, now unfortunately very rare in the state, has very obvious facial discs giving them a monkey face look. The owl species with the largest facial disks is also the largest owl, the great gray owl. “Great grays,” for the most part, live in northern Canada where more snow falls and remains on the ground much longer. Great gray owls have such great hearing that they can detect the sound of a mouse moving under the snow.
Finally, keeping with the owls, they have another great adaptation. Their wings are all edged with softer, fringed feathers. Hawks and eagles have stiffer feathers and stiffer feather edges. The owls feather adaptation allows them to fly “super” quietly giving them an edge over many night active prey animals that also have retinas packed with rods. An owl’s flight is almost undetectable.
Test Your Outdoor Knowledge: Owls have tremendous night vision, but no sense of smell. True/false: Deer have great night vision, average color vision, and like owls, have a poor sense of smell?
Last Week’s Trivia Answer: Chipmunks and striped skunks both use winter dormancy (winter sleep) during winter’s coldest months.
Email Barry Reed at firstname.lastname@example.org