*Editor’s note: This guest column was submitted by Observatory Hill resident David Bennett, with the support of City of Pittsburgh Park Ranger Nancy Schaefer.
By David Bennett | Contributor
We are lucky to have owls living in Riverview Park. Two of the species most often reported by birders are great horned and screech owls.
Screech owls are rather small owls that generally live in the cavity of a tree. These owls don’t actually screech, but are well known for their whinnying descending trill call that sounds more like a horse than an owl.
One screech owl can eat at least 1,000 mice a year, but also earthworms, large insects and frogs, so you can imagine how beneficial they are in the local ecosystem. Screech owls hunt at night, but you can sometimes see them perched high in the cavity of a tree, enjoying a bit of sunshine. We have gray and red morph screech owls in Riverview, and the two often interbreed.
Great horned owls are much larger, and are apex predators, sometimes eating screech owls, small hawks, rats, mice, rabbits, squirrels and opossums.
Great horned owls are one of the few predators that regularly eat skunks. Because of the great horned owl’s poor sense of smell, they are immune to the skunk’s main defensive weapon.
Owls have a delicate velvety fringe on the trailing edge of their feathers that allows them to be stealth flyers. They are able to silently swoop in and listen for prey.
Great horned owls don’t build nests; they typically steal nests made by hawks, crows, ospreys, squirrels and even bald eagles. They will also sometimes nest in the cavity of a tree.
The territory of a nesting pair of great horned owls is 1.5 square miles, which is considerably larger than Riverview Park, so nearby residents will often hear the owls calling outside the park, particularly in the month of November, to establish their territory. Their call is typically three hoots, followed by two additional hoots.
Both species of owls are helpful in maintaining a healthy balance of wildlife within Riverview Park.