The Carlisle Mosquito Online

Friday, February 7, 2003

Features


Great Horned Owl

Drawing by Laura Bortolin
Name: Great Horned Owl or Bubo virginianus. The species name refers to the Virginia colonies where the Great Horned Owl was first seen. It is also known as the cat owl, hoot owl and winged tiger. There are many subspecies.

When and where seen: Three were counted in the Carlisle Christmas Bird count in December 2002. I heard one frequently during November and December anytime from dusk through midnight. I also heard one in the Towle woods just before Christmas, at around 4:30 p.m. Christina Campbell, who reported last week on her sighting of the large number of coyotes on the Concord River, the same night saw a very large owl with tufts on its head. This was almost certainly a great horned owl.

Voice: "Hoo, hoo hoo, hooo hooo-hooo"; four to seven low, booming, rhythmic hoots that can carry distances of several miles. I sometimes hear the hooting in bed at night with all the windows closed. Great horned owls also make barking and shrieking sounds. You can listen to examples of all these sounds at www.owlpages.com.

Appearance:. BIG bird. The average length of adults is 22 inches from tip of beak to tip of tail and the wing span is in the range of 36 to 60 inches. The upper parts vary in color from reddish brown to sooty brown to brownish-gray. The underside has dark bars and the throat is white. The face of the eastern subspecies is tawny-orange, and the eyes are yellow. The great horned owl is most easily identified by the feather tufts or "horns" on the head. If you see a large owl with "horns", it is the great horned owl. The long-eared owl also has "horns" but it is a much smaller bird at about 15 inches long and it doesn't have a white throat.

Food: The great horned owl prefers to prey on small mammals like rabbits, rats, mice, squirrels, and skunks. A domestic cat is vulnerable. It will also take birds, including other owls, as well as reptiles, amphibians and insects. The food is eaten whole and the unwanted bones, fur and feathers are compacted and regurgitated. "Tastes great less filling." A pile of regurgitated pellets will indicate the location of a regular roosting place.

Nesting: Right now is the courting season for great horned owls. You may hear males and females hooting to each other. They will use the abandoned stick nest of another bird (such as a hawk, crow or heron) for the incubation of two or three eggs which hatch in about four weeks. Great horned owls are very aggressive in the protection of their young.

References: www.owlpages.com; Ken Harte for the Christmas Bird Count chart; University of Michigan Museum of Zoology; David Allen Sibley, The Sibley Guide to Bird Life and Behavior.


2003 The Carlisle Mosquito