By Tom Warren

In the night sky over the Monadnock region a tiny forest owl about 8” long is migrating. However, a number of these owls remain in our region all winter.

A few facts about owls: Owls have large eyes and their vision is 2 to 3 times better than humans and can admit 3 times as much light as ours. They can focus their eyes 10 times faster than humans so that they can see obstacles quickly.

They have asymmetrical ears (one higher than the other) and this allows them to perceive sound sooner in one ear than the other ear, as little as 3/100,000 of a second which means that they can locate sound with remarkable accuracy. It is with their ears, not their eyes that allow them to capture much of their prey, which occurs mostly in the dark. Their large facial disk also aids in the amplification of sound.

Female owls are 40% heavier than males.

The Saw Whet Owl, the smallest of our owls is this area has long, broad wings with a wingspan of 17-21 inches and relatively light wing loading, which allows it to fly through heavy shrubs and trees. Wing loading is the amount of body weight supported by a small area of the wing.

The Saw Whet Owl nests in holes in trees, usually those cavities made from Flickers and Pileated Woodpeckers. They will also nest in bird boxes. Between the months of March and July, the female lays 5-6 eggs, which will hatch in 28 days. In another 30 days the young leave the nest cavity.

They eat a large number of mice, voles, red squirrels as well as small numbers of birds during migration. They eat their own weight in mice every 3-4 days.

They have 9 different vocalizations with the most common being a whistled toot note, which can be used to call them out of the forest on fall and winter nights. They also make loud, sharp squeaking calls that sound like a farmer or forester filing a large mill saw. It gets its name from this call note.

On several occasions I have been able to call this owl from the forest by mimicking its call note. On two occasions, the owl picked my woolen hat from my head before realizing it was not a mouse or that I was the “other” owl.

The Saw Whet Owl has been the subject of one of the major banding projects by Antioch graduate student, Chris Volonte. Her research the past three years has revealed that hundreds of these owls are migrating through the region in October and November.

Tom Warren, a Dublin resident, is a Trustee of the Harris Center for Conservation Education and New Hampshire Audubon.


Night Line – The Saw Whet Owl