Here we are on Tuesday in the Pacific Northwest of North America, so it’s time again for Monochrome Madness over on Leanne Cole’s blog. She has a lot of new participants in the challenge this week, so head on over and check them out!
I’m back to posting images of critters again this week, and this Great Horned Owl (Bubo virginianus) moved into the bird sanctuary back in the fall, presumably from somewhere further north. Most of these guys tend not to migrate, but some of those who live up north will do so. This magnificent creature didn’t seem too bothered by my presence at all, s/he’s glaring at me here, but slept through most of the visitors. S/he’s actually safely tucked away in a very high tree, tho it doesn’t look like it in this image.
Great Horned Owls hunt by perching on snags and poles and watching for prey, or by gliding slowly above the ground. From high perches they dive down to the ground with wings folded, before snatching prey. Prey are usually killed instantly when grasped by its large talons. They also hunt by walking on the ground to capture small prey or wading into water to snatch frogs and fish. They have been known to walk into chicken coops to take domestic fowl. Rodents and small rabbits can be swallowed whole while larger prey are carried off and ripped apart at feeding perches or at the nest. Birds are often plucked first, and legs and wing tips discarded. An extremely wide range of prey species (over 250 identified) are captured, but rabbits and hares are its preferred prey. Mammalian prey includes all coexisting rodents, squirrels, mink, skunks, raccoons, armadillos, porcupines, shrews, moles, muskrats, and bats. They may sometimes take small domestic dogs and cats. Bird prey includes all other Owls (except Snowy Owl), grouse, woodpeckers, crows, turkeys, pigeons, Red-tailed Hawks, bitterns, Great Blue Heron, ducks, swans, gulls, etc. Reptiles include snakes, turtles, lizards, and young alligators. Amphibians include frogs, toads, and salamanders. Other foods include fish, large insects, scorpions, centipedes, crayfish, worms, spiders, and road killed animals. A Great Horned Owl is powerful enough to take prey 2 to 3 times heavier than itself.
Nesting season is in January or February when the males and females hoot to each other. When close they bow to each other, with drooped wings. Mutual bill rubbing and preening also occurs. They do not build a nest of their own but utilize the nests of other birds such as the hawk, crow and heron. They may also use squirrel nests, hollows in trees, rocky caves, clumps of witches broom, abandoned buildings, or on artificial platforms. They are extremely aggressive when defending the nest and will continue to attack until the intruder is killed or driven off. Families remain loosely associated during summer before young disperse in the autumn. Adults tend to remain near their breeding areas year-round while juveniles disperse widely, over 250 km in the autumn. Territories are maintained by the same pair for as many as 8 consecutive years, however, these Owls are solitary in nature, only staying with their mate during the nesting season. Average home ranges in various studies have been shown to be approximately 2.5 square kms.
A long-lived Owl, captive birds have been known to live 29 to 38 years, and wild Owls up to 13 years. Most mortality is related to man – shootings, traps, road kills and electrocutions. The only natural enemies are other Great Horned Owls and, occasionally, Northern Goshawks during disputes over nest sites. Peregrine Falcons have also been observed attacking Great Horned Owls.
Great Horned Owls are found throughout North America from the northern treeline and then in Central and South America. They are resident year-round, however, birds living in the northern part of the species’ range may migrate south.