This Food is for the Birds

Nature Watch
December 21, 2007

By Susan Benson
Director of Education
Cable Natural History Museum

I returned home late one evening last week and was walking up to the house when I heard it. Actually, I felt it more than I heard it. There was a deep resonant sound that beat in my chest. I stopped. It was about 25-degrees, and my breath formed small clouds as I stood in the driveway listening. Then, from out of the forest came a deep voice: Who’s awake? Me too. A quieter, single-note response followed from a second bird and then the silence returned. The male owl repeated his question and answer: Who’s awake? Me too, and the female bird responded again with a single note. After listening for a few minutes, I went into the house. It was clear that this conversation between a pair of Great Horned Owls would continue for a while.

There are eight species of owls that nest in Wisconsin, but only about half of them can be found in Bayfield County. The Great Horned Owl is perhaps the best known of these because it is found in every Wisconsin county, and because it is the most “owl-looking” owl. Even if people don’t know this common species by name, they likely think of it whenever someone says the word “owl.”

Great Horned Owls are large birds, nearly two-feet tall, with yellow eyes and feather tufts that stick up on each side of the head like ears. In our area, only the Barred Owl comes closest in height, standing 21-inches high. But Great Horned Owls can be distinguished from Barred Owls by their eyes. Barred Owls are one of only four species that have dark brown eyes rather than the piercing, bright yellow eyes found on the Great Horned and 14 other owl species in North America.

I heard the Great Horned Owls calling that evening because these dark nights and cold days of winter are the beginning of the mating season for them and most other owls. Adults are calling back and forth to each other, looking for mates and cementing relationships. They will soon be building nests and settling down to lay eggs and raise young. In Wisconsin, eggs are laid as early as February 6, and the first young are hatching a little over one month later.

Habitat for the Great Horned Owl varies from the deciduous woodlands between open grass- and croplands, to gaps within the heavily wooded northern forest. They feed on a wide variety of small birds, mammals, and snakes, but their favorite foods are mice and cottontail rabbits. Nests are typically made of large sticks, but the owls do not build a nest themselves. Instead, they will take one over that has been built by some other bird, usually Red-tailed Hawks, but sometimes ravens or the occasional squirrel. The Red-tailed Hawk nests are particularly favored because the hawks migrate and do not return before owl nesting begins. Great Horned Owls also nest in tree cavities and stumps, and even occasionally (but rarely) on the ground.

Great Horned Owls, like most of their other relatives, are most active at night. With a bit of searching, you might find one roosting high in a tree during the day, often sitting right next to the trunk. I once found one in Ashland’s Prentice Park, perched among the bare branches of an aspen tree. I could see its yellow eyes clearly burning right into me even from the great distance that separated us.

If you are fascinated by these birds like I am, you might want to join me on one of the “Owl Prowls” sponsored by the Cable Natural History Museum. One evening a month from June through October, I take people out into the woods to call for owls. Usually we only see Barred Owls, but we are sometimes lucky enough to find a Great Horned Owl or perhaps one of the more uncommon species such as the tiny Northern Saw-whet Owl. Incidentally, if you would like to hear an exchange between a male and female Great Horned Owl like the one I heard a few nights ago, you can find a recording from California on online at www.owling.com/Great_Horned.htm#recordings. Click on the recording labeled “Silverado Canyon, California, October 2000” on the far right. You can also hear the Great Horned Owl and the other species found in Wisconsin at the Museum’s Owl Booth, which is part of our “Birds in Focus” exhibit. Stop in and listen to “who’s awake?” and “who cooks for you all?”!

Nature Watch is brought to you by the Cable Natural History Museum. For 40 years, the Museum has served as a guide and mentor to generations of visitors and residents interested in learning to better appreciate and care for the extraordinary natural resources of the region. The Museum invites you to visit its facility in Cable at 43570 Kavanaugh Street or on the web at www.cablemuseum.org to learn more about exhibits and programs.