This week’s owl captures picked up from last week, mostly thanks to five captures on the night of the 24th. For the week, nine Northern Saw-whet Owls (NSWO) and one Long-eared Owl (LEOW) were banded. April 24thwas the most eventful night of the week, with the 100th owl of the season captured and the first confirmed male owl of the season.
Like last week’s Barred Owl, this week’s LEOW came in to the NSWO audio lure. As with the last LEOW captured, this bird was an adult female.
This female NSWO was the 100th owl captured for the season. She also had a well-developed brood patch: a bare patch on the belly lacking feathers that allows head to be efficiently transferred to eggs during incubation. Since brood patches this time of year mean a bird is getting ready to nest or already nesting, I have to wonder if this bird was a local breeder.
Since male NSWO are generally smaller than females, banders determine the sex of NSWO using a combination of mass and wing chord (wing length), although there is an overlap causing many intermediate-sized birds to be classified as unknown. The majority of NSWO captured this year have been females, with a few likely males towards the lower end of the overlap zone between the sexes.
Shortly before I banded the 100th bird (a female) on the night of the 24th, I banded the first confirmed male NSWO of the season (photo above). It is my hand in both photos – notice how much smaller the male is than the female also pictured in this post!
-Evan Buck, spring 2022 owl bander
Breakdown of each night’s catch:
|Date||Newly Banded NSWO||Recaptured NSWO||Newly Banded LEOW|
Note: recaptures originally banded spring 2022 at Mill Creek Historic Park are not included.