I almost ran over it. At first it was just a lump in the road, then the head slowly turned (with something in its bill) and I hit the brakes, stopping just in time. As I slowly started to back up, the barred owl took wing, landing 30 feet away.
It was night, but the headlights provided light to see the owl, about 20 inches long with a weightlifter’s neck, dark eyes, large rounded head, brown barring on the breast, and a seemingly fearless attitude. We stared at each other for three or four minutes before it flew into the trees.
Barred owls’ traditional habitat has been Eastern forests but the owls have moved west and live in mostly second-growth forests. The first barred owl was identified in Washington in 1965.
Owls draw a lot of attention in part because of their ability to swivel their heads up to 270 degrees in either direction. Their eyes are set more toward the front of the head (rather than the eyes of most avian species, set to the side). The downsides to that placement are that the field of view for each eye is smaller and it leaves a blind spot behind the head. The upside: the visual fields overlap more in front to give a bird good depth perception and to distinguish distance.
Owls’ eyes are tubular rather than spherical. A tube-shaped eye provides a larger retinal image and owl-sized eyes provide outstanding night vision, a major factor in tracking down small prey in the dark.
It hasn’t been until recently that researchers zeroed in on how owls swivel their necks. Why don’t they damage the delicate blood vessels in their necks and heads and cut off the blood supply to their brains?
Using angiography, CT scans and medical illustrations, researchers from Johns Hopkins University found four adaptations that allow the injury-free swivels.
“Until now, brain-imaging specialists like me who deal with human injuries caused by trauma to arteries in the head and neck have always been puzzled as to why rapid, twisting head movements did not leave thousands of owls lying dead on the forest floor from stroke,” said study senior investigator Philippe Gailloud in a 2013 report.
The team found that the bone structure and vascular system in the heads and necks of owls have uniquely constructed necks and arterial systems that feed blood to the brain even while they are twisting their necks.
One adaptation is in the neck, where a major artery feeding the brain passes through bony holes in the vertebrae. The hollow cavities are about 10 times larger in diameter than the vertebral artery traveling through it. The extra space creates air-cushioning pockets that allow the artery to move around when twisted.
Just goes to show what you might find out when you keep your eyes on the road.
Columnist Sharon Wootton: 360-468-3964 or www.songandword.com.
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