Sharp eyes fail

You would think that birds, especially owls, with their exceptional eyesight would be able to see the finest details and avoid trouble. They do -- most of the time.

An owl got into trouble recently on the Lazy Z Ranch, just east of Sisters.

Angie Spencer, a lovely young lady who pushes water (irrigation) for the Lazy Z, found it twisted up in the top strand of a barbed wire fence on the ranch.

Angie noticed the owl had a broken wing and knew what to do and how to get it out of the fence without causing further damage to the bird. After placing it in a container she called the vet and the owl was on its way to recovery, if the broken wing could be saved.

How did an owl got itself tangled up in a barbed wire fence? Easy.

When owls (and hawks and eagles as well) spot what they want to eat, they can actually zoom in on that object, thanks to the central and temporal fovea in the retina -- but everything else is out of focus.

Neither Angie nor I were there when the owl hit the fence, but it's safe to say that it was swooping into the field after a gopher and just didn't see the wire between itself and the meal it was after.

The legendary eyesight of owls is part of a complicated design.

Most owls have a facial disk and a somewhat flat face with eyes that are forward looking. This provides phenomenal binocular vision. In the case of great horned owls, their eyes are larger than their brain.

The usual hunting stance of owls is to perch quietly on a tree, fence post or pole and watch everything around them.

Most owls can turn their heads almost 270 degrees without stopping -- but not 360. This stealthy hunting technique enables them to note the slightest movement -- thanks to about a million visual cells per millimeter in each eye.

However, there are a few limitations to this design -- the bulk of the eyes being one. Because the owls' eyes are so large they are encased in their skull in such a way that they can not move them; they're held firmly in place by a thin, bony structure known as the sclerotic ring.

If we humans want to see something to the side, above or below, we can easily move our eyes in those directions. Owls cannot do that; they have to move their entire head. To compensate, they have twice the number of vertebrae in their neck as you and I, which makes it easier to rotate their head.

Years ago, Sam Moorhouse, an old buckaroo from the Fort Rock country, pulled a good one on me.

"Hey, Jim," he drawled as we met at Reub Long's ranch in the shadow of Fort Rock, "I seen one of them little cuckoo owls (burrowing owls) the other day and he twisted his head clear round."

"Oh, sure, Sam," I replied skeptically.

"No kiddin', it really did," Sam insisted. "That little owl was sittin' on the top of an old fence post and me and my horse rode clear 'round him four times and he just kept turning his head 'round and 'round."

"You bet, Sam," I replied.

"It did, honest," he said. "Then you know what happened?"

"Yeah," I answered, "The owl's head fell off."

"Nope," Sam said with a twinkle in his eye. "My horse got dizzy and fell down."

About that owl at the Lazy Z: When last heard from, the owl was doing as well as could be expected and the wing was healing. Will it go back into the wild? It's too soon to tell.