Wednesday, April 22, 2015

Well owl be...

Today I wanted to enlighten you about another little enclave of biodiversity -- owls. During my time on the airport I've had the great joy of observing four species of owl! Now some of them we have trapped and relocated, while others I've merely seen from afar.
First the ones we've successfully trapped and had relocated far away from the airport: Barn Owls (Tyto alba) and Great Horned Owls (Bubo virginiaus); Barn Owls are year-round residents to area and hunt by night for rodents; in our case here at the airport that means pocket gophers.

Barn Owl on a runway sign at night.
Great Horned Owl in a Swedish Goshawk trap.
Great Horned Owls are also year-round residents to the area, which I was initially surprised to learn as the last time I saw one was on our apartment balcony in Wyoming. GHOW's, as birders identify them, hunt rodents and rabbits, and just about everything else under the moon!
"Great Horned Owls have the most diverse diet of all North American raptors. Their prey range in size from tiny rodents and scorpions to hares, skunks, geese, and raptors. They eat mostly mammals and birds—especially rabbits, hares, mice, and American Coots, but also many other species including voles, moles, shrews, rats, gophers, chipmunks, squirrels, woodchucks, marmots, prairie dogs, bats, skunks, house cats, porcupines, ducks, loons, mergansers, grebes, rails, owls, hawks, crows, ravens, doves, and starlings. They supplement their diet with reptiles, insects, fish, invertebrates, and sometimes carrion." -- The Cornell Lab of Ornithology All About Birds

Do you see his nictitating membranes?
Burrowing Owl

Short-eared Owl
Now I've also seen Burrowing Owls (Athene cunicularia) which pause at the airport while migrating, as I've never seen them here for much longer than a few weeks at a time even though guidebooks show them as "year-round residents" throughout the southwestern boarder states. An interesting thing about Burrowing Owls: they exhibit no sexual dimorphism unlike most of their cousins where the females are larger. And the ones that stop by the airport mainly feast on beetle, which we have a pretty good supply of.  One more cool thing about Burrowing Owls is that they are diurnal, means active during the day.
A Burrowing Owl pellet to the right. That's a lot of beetle shells!



The other owl which I got only a fleeing glimpse and subsequent photo of is a Short-eared Owl (Asio flammeus) -- at the time I honestly didn't know what I had gotten a photo of until I reviewed it and perused my field guide, which also told me that unlike all of the previously mentioned owls, Short-eared Owl are only in the region during winter. Like Great Horned Owls they do hunt when ever it suits them -- day or night.

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