Saw-whet captures have varied widely from year ... They use a blacklight to look at the underside of the owls’ wings and see their molt pattern, which helps determine their ages, a difficult ...

Once believed to be a threatened species in Pennsylvania, saw-whets are actually more common than previously thought.

They range in size from about seven or eight to ten inches in length, with wing spans of about 17 to ... especially during the nesting season. A saw-whet owl stands quietly, just observing.

Fedak demonstrated how an ultra-violet light was used to age the owls. Saw-whet wing feathers contain a pigment called porphyrin, which glows pink under UV light. New feathers glow more brightly ...