Northern Saw-Whet Owls

“I shall never forget the thrill I experienced when I first met this lovely little owl. … I had never seen so small an owl, or one so beautiful.”  Arthur Cleveland Bent, Life Histories of North American Birds of Prey, Part 2, August 8, 1938.

Mr. Bent was writing about the northern saw-whet owl.  Of the eight Ohio owl species the saw-whet is the smallest.  These little owls are nocturnal and elusive.  There may be a few of these owls that call Ohio home year-round, but the vast majority spend their summers in northern forests across Canada and from Alaska to the New England states. They are winter migrants to Ohio flying south from their northern breeding grounds to find shelter and food.  Their fall migration occurs from October through mid-December.  They find shelter in dense evergreen and conifer trees such as fir, pine and spruce trees.  And often these trees are near freshwater sources such as lakes, creeks and bogs. Saw-whets are not easy to see; first, they’re nocturnal and second, they survive during the day by disappearing into their surroundings.  They will roost motionless, camouflaged by their colors and markings and hidden by the branches of their chosen hiding spot.  While saw-whets are seldom seen during winter they are probably the most common owl calling Ohio home.

This little owl is built for the night!  Their bright yellow eyes are huge. If human eyes were as large proportionally as a saw-whet’s, they would be the size of a grapefruit.  Their retinas are packed with far more rods than cones.  Rods work in the dimmest light levels allowing the eye to see only in shades of gray, called scotopic vision.  Not as necessary for this owl, cones work in bright light allowing the eye to perceive color.   Compared to the size of their skull, saw-whets might have the largest ears of any animal.  All owls have asymmetrical ears but saw-whet’s have the most asymmetrical ears of any owl species. Not only is one ear a little higher than the other but the left ear, located low on the head, faces downward and the right ear that is higher faces upward. In addition, each ear is also shaped slightly differently than the other.  This owl will tilt its head until sounds reach both ear openings at the same time allowing them to instantly pinpoint and target their prey with incredible accuracy.  Their flight feathers are fringed with soft comblike extensions that muffle the sound of flight.  Their feet are strong, and the sharpness of their talons have been compared to a hypodermic needle.  Their prey, consisting mostly of rodents, don’t have a chance. Saw-whets will cache extra food in various locations. During winter the cached food may freeze.  They thaw the frozen carcasses by laying on them just like they are incubating eggs.

Saw-whets play a vital role in keeping ecosystem balance by controlling prey animal populations.  They are also considered an indicator species for forest health as they depend on mature forest habitats with cavity nesting sites.  The northern saw-whet is one very impressive little owl.  It hunts at night, mates at night and migrates at night. It needs the dark of night to thrive.  Owls, because of their scotopic vision, are particularly vulnerable to light pollution and the impacts of short wavelength blue light.  Long term exposure to light at night can cause permanent damage to an owl’s eyes.  Let’s turn off all unnecessary lights to help these owls continue to thrive at night and continue to play their part in the ecosystem.