In the last Nature Nut column, I mentioned the preparations many animals make for winter, including those who migrate south for winter.
One of the most interesting of these winter migrants is the Saw Whet Owl.
These miniature looking owls, smallest in Minnesota at less than a quarter pound, move silently through the state in large numbers from further north each fall. Even though I would estimate there are hundreds of thousands of these ‘furballs’ passing through woods, fields
and even many backyards, they are almost totally unknown to most state residents.
Flying silently, as most owls do, and moving almost totally in the dark of night, Saw Whets are rarely seen by humans.
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Unlike many of our resident owls, such as the small Screech Owls or large Barred and Great Horned varieties, the Saw Whets don’t do much vocalizing, except in their breeding grounds further north.
Over the past few decades bird banders, including myself, have tried to learn more about these elusive birds by capturing them in fine mist nets. Audio lures are used to draw them in on dark fall nights when we might net five to 10 birds in forests near Rochester or the Weaver Bottoms near Kellogg.
Nights when the moon is crescent or absent seem to work best as these little owls may not move or hunt much on bright nights for fear of being hunted themselves by larger owls.
Some northern Minnesota banders often catch dozens, or more than a hundred owls, on some nights.
Once captured, the owls are examined carefully to try to determine gender and age. Gender is based upon weight and measurement of wing length, with females usually larger than males.
Age is determined by close examination of the wing underside under a black light that reveals pink coloration in different amounts depending upon how old the bird is. A small aluminum tag is then placed on the lower leg giving the owls an identification number.
When all is done, birds are released to go about their southward movement in search of field mice, their favorite food, which they may tear in half for two meals.
Because the owls move late at night, it is difficult to do programs or involve members of the public in the owl banding. However, this year we have been able to collaborate with a professor and students from St. Olaf College to study the owls.
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Students spending the night at the Weaver Dunes Nature Conservancy Field Station have been able to take part in the owl banding on several nights. Many found the owls are amazingly docile as they lay upside down on the digital scale, or perch on their shoulder for pictures that are soon posted on FaceBook.
Although the late nights get a bit harder each year, we hope to continue catching owls in future years to learn more about these amazing little birds which may be flying silently through your backyard.
