This Halloween Owl Visitor to PA is a Frightening Predator

October 24, 2014

Our smallest owl in the eastern United States—the northern saw-whet owl—is literally the size of a pint glass. A mere seven inches in height with a large, round head and blazing pumpkin-colored eyes, it is arguably one of the most adorable birds in North America. Nevertheless, saw-whets are frighteningly good predators. To quote the Cornell Lab of Ornithology: “Where mice and other small mammals are concerned, this fierce, silent owl is anything but cute.”

Northern saw-whets' favorite prey are mice, but they’ll also devour the occasional beetle, bird—or even bat. They begin their nightly breakfast hunts not long after sunset and search for lunch around 2 a.m. They often consume only half of their second meal—usually just the head and shoulders, brains and all—and save the rest for a midday snack. If their stashed morsel is frozen, they’ll tuck it into their belly and warm it up before devouring the rest.

Each and every fall, many saw-whet owls migrate south from Canada and the northern U.S. to spend their winters in the balmy southern or central United States. In years after rodent population booms, saw-whets come south by the thousands during October and November. The median arrival date here in Pennsylvania is—you guessed it—Halloween. 

Researchers use ultraviolet lights to determine the owls' age. Fresh wing feathers are fluorescent under UV light, while older feathers are more gloomy. Photo courtesy Luke DeGroote

So while children take to the streets, researchers will haunt the forests to study this mysterious owl. They’ll lure them in with the “toot toot toot” call using a car stereo amplifier, speakers and tractor battery "Frankensteined" together.  

Researchers with Project Owlnet use ultraviolet lights to determine the owls' age. Fresh wing feathers are fluorescent under UV light, while older feathers are more gloomy. Finally, they will assess each bird’s condition and affix a small, numbered metal band to track them over time. But you don’t have to have this special equipment to appreciate the northern saw-whet owl. As you’re out walking in the cover of darkness this Halloween, keep an ear out for their eerie fall conversation. You might just hear something both spine-chilling—and amazing.

Locally, you may have a better chance of seeing the northern saw-whet owls—and Project Owlnet researchers at work—in November at Sewickley Heights Borough Park in Pittsburgh, Ned Smith Nature Center in eastern Pennsylvania and Valley Falls State Park in West Virginia.

Bird calls for the audio recording of this segment come from The Macaulay Library at the Cornell Lab of Ornithology, recorded by William W. H. Gunn, Geoffrey A.. Keller, and Scott Weidensaul.