Photo: Scott Weidensaul. Little larger than a robin, northern saw-whet owls were long considered rare in the East.

Our thanks to Green Blog for this wonderful item:

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.
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