December 5, 2012
Blogs, U.S.

Tracking a parliament of tiny owls

By RACHEL NUWER | Green | December 4, 2012 |

Each autumn, thousands of miniature owls fill the night skies in the Northeast, gliding over forests and fields, suburbs and cities. They cast minuscule shadows as they breeze by the Empire State Building. Where they are headed, no one knows exactly. But researchers are certain of one point: there are many, many more of these little raptors, known as northern saw-whet owls, than they had suspected.

“This is a little bit of the Canadian wilderness passing through,” said Scott Weidensaul, a natural history writer who has coordinated volunteer research on saw-whet owls for 16 years. “Pretty much wherever you live in the Northeast or even in other parts of North America, there are tiny owls weighing no more than robins flying over your house.”

Measuring about seven inches long, the northern saw-whet owl is one of the smallest owl species in North America. With its huge yellow eyes and handsome mane of creamy brown feathers, it is “cosmically cute,” Mr. Weidensaul said, and thus intriguing to both devoted bird watchers and the general public. But until recently, ornithologists considered these elusive birds from Canada to be quite scarce in many parts of the United States. “I’d been a birder my whole life and I think I saw one saw-whet in 40-odd years,” Mr. Weidensaul said.

As it turns out, however, saw-whets are not rare at all; they are just difficult to spot. In 1996, after hearing rumors of large numbers of saw-whets being netted on the Eastern Shore, one of Mr. Weidensaul’s colleagues set up backyard nets in eastern Pennsylvania. He caught 80 of the small owls. “At that point, we realized that the widespread assumption that saw-whets were rare had to be wrong,” Mr. Weidensaul said.

He secured a small start-up grant to create a network of owl banding stations in Pennsylvania. That autumn, he and a couple of biologist colleagues set up three field stations with the Ned Smith Center for Nature and Art in Millersburg, Pa., and recruited around 100 volunteers, from wildlife experts to housewives to plumbers. In 1998, the project gained further momentum when Mr. Weidensaul became the Pennsylvania volunteer coordinator for Project Owlnet, a collaborative saw-whet owl-banding network created by Dave Brinker, an ecologist with the Maryland Department of Natural Resources.

For the last 15 years, each evening at dusk between October and November, the volunteer crew has set up a line of mist nets, or veils of nearly invisible nylon mesh that ornithologists often use for safely snaring wild birds, in the woods. To attract curious owls, they play male saw-whet calls, a “high-pitch tooting” that resembles the sound of a garbage truck backing up, Mr. Weidensaul said.

Since the project began, the team has banded more than 10,000 saw-whet owls. This fall it secured extra funds for several new field stations and for equipping 39 saw-whets with radio transmitters so they could more closely follow their movements. All in all, they caught 3,677 saw-whets this season, 118 of which already carried bands from previous encounters in Ontario, Quebec, Pennsylvania and beyond.

When Mr. Weidensaul and other saw-whet enthusiasts around the country recapture banded owls, they share the data on a Listserv to better track the animals’ migration routes. This way, the Owlnet community can share notes on migratory routes and timing and on owl longevity. The data is also freely available to researchers who want to perform their own analyses. “It’s all a question of connecting the dots,” Mr. Weidensaul said.

Mr. Weidensaul says he hopes the saw-whets pass on a lesson of their own to the many volunteers, some of whom are as young as 11, that dedicate their time to the Ned Smith Center. “When you put an owl on the head or shoulder of a fourth grader, it creates a spark of interest in conservation and ornithology in someone who may not have had it before,” he said. “A number of kids have grown up in our project over the past 15 years, and some are now off doing amazing things in the field of science.”

The work may also help inform development decisions. Several hundred wind turbines already operate on the saw-whet’s migratory routes, and more may rise in years to come. Mr. Weidensaul often receives calls from turbine consultants asking how many owls are passing through, where they are going and at what altitude. Much of this information is still lacking, however. No one yet knows where the saw-whets wind up on their southern journey, for example, though birds have turned up as far south as Atlanta and Birmingham.

“You can’t preserve something about which you know very little, and I have more questions now than when we started 16 years ago,” Mr. Weidensaul said. “The natural world is bigger and more astonishing than we realize, even when it’s literally happening in our backyards.”

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