“At night in the fall there are probably these little owls about the size of a soda can that weigh as much as a robin flying over [your] house and we're completely oblivious to it.” Scott Weidensaul in an interview with Terry Gross for Fresh Air, Oct. 20 2015. You can find the whole fascinating interview here.
That little soda can is the Northern Saw-whet Owl, a secretive Wisconsin breeder usually heard, rarely seen. If seen you'll notice their small size, yellow eyes, and dark beak. They may be confused with short-eared owls but can be distinguished by being much smaller and having reddish facial disks without a dark border. You also might wonder, why saw-whet? The sound of a saw on a whetsone resembles the owl's incessant call, which Scott Weidensaul called “psychosis inducing” after spending nights netting saw-whet owls by attracting them with 110 decibel calls. You might also wonder what a whetstone is—it's a fine stone used for sharpening tools.
Weidensaul annually nets about 500 saw-whet owls in migration at the Ned Smith Center in Pennsylvania. The first Wisconsin Breeding Bird Atlas reported 73 records of saw-whet owls over a five year period. So far, birders for the second Wisconsin Atlas have seen only a handful of breeding saw-whet owls throughout the state, mostly in northern counties. There may be a very small number of saw-whet owls in the Wisconsin, with larger numbers moving through during migration, or there may be a bias in recognizing the species. Atlases and Christmas Bird Counts don't do a great job of finding this nocturnal species.
Saw-whet Owls prefer dense woodland or occasionally savanna, often conifer or mixed forest. Obligate cavity nesters, the birds need dead trees for their survival. They will readily take to nest boxes, however.
The owls will overwinter in southern Wisconsin and feed on small mammals like deer mice, white-footed mice, and chipmunks. With young, females incubate and brood, while males provide almost all of the food. Males will continue to provide food after fledgling.
Saw-whet Owls exhibit a number of cool traits, such as controlling their head in order to keep their eyes on prey while executing aerial maneuvers. The owls also have asymmetrical facial disks, which allows them to exact stunning hunting intuition. An interesting tidbit is that you can see the eye of a Saw-whet Owl through its ear hole.
At Faville Grove, we found a perished Saw-whet Owl a few weeks ago. Upon closer inspection, the eye was visible behind the bird's facial disk! This interesting bird also had a mouse in its talons, and the specimen was a random way to discover that the furtive birds use the sanctuary over winter.
This March, you'd be lucky to see a Saw-whet Owl near the conifer planting along Faville Woods. The owls tolerate close approach without flushing, so if you stumble within inches of a saw-whet, look for the back of its eye through its ear!
Written by Drew Harry, Faville Grove Land Steward