Listening for our Great Horned Owls this winter...

On cold winter nights in December and January, I often listen for our local Great Horned Owl couple as they hoot back and forth from the treetops, calling out to each other in amorous devotion. All is quiet outside when they come through our neighborhood, and their sleepy and soothing calls flow easily in on the cold air. As I kneel beside the open window, looking out into the night, I always hope to see one fly by the window or see a silhouette of one perched against the moon, but I never do. These night creatures are for hearing only it seems, but in the cold and quiet of a winter's deep night, hearing is enough, and it might even be best because I see them through the sparkly eyes of moonlit imagination. Tonight the temperature will dip into the 30s again, and when I wake a hard frost will cover the plants and rocks and any other objects that got in its way, reminding me that I'll soon hear our two owls outside my window as they travel through the cold night...

Great Horned Owl (Bubo virginianus)

This owl's name is Sylvester, and he is another of RAPTOR, Inc.'s education birds. He's been around for a while, having been rescued in 1997. He was found with wing and leg fractures at the Lawrenceburg exit of I-275...hit by a car. Adult Great Horned Owls really have no natural enemies. Even a Bald Eagle will think twice before nesting in a Great Horned Owl's territory, so it was no surprise to see this bird was injured by humans. With its huge talons, it is one of our most powerful birds of prey. Sylvester is 22 inches long with a wingspan of 4 feet...needless to say, he was impressive sitting on the perch in front of us.

Great Horned Owls live in North America year round, but in our yard we usually only hear them hooting back and forth in late November, December, and January. This is when their courtship, which can start as early as September, really picks up. By January they have set up their territory and have selected their nest site. The female can lay eggs as early as mid or late January. Once the eggs are laid, the vocalizations calm down, and their calls become sporadic. We think the couple that visits our yard is a young pair. The first time we heard them hooting back and forth was January 12, 2009. In 2010 they became regulars. I hope they return to the same territory, and we get to hear them again this winter.

I had never heard the Great Horned Owl's nickname of "Cat Owl," but it was pretty easy to figure out where the name came from. The tufts of feathers that form the "horns" on their heads look like cat ears. Of course the ear tufts are not ears at all. The owl's ears are on its face, hidden beneath feathers and located below and behind the eyes.

Huge eyes...

A Great Horned Owl's eyes are about the size and weight of a human's eyes, but proportionately they take up a larger part of their face. If we compare our eyes proportionately to a Great Horned Owl's, they would be the size of tennis balls! (Source: "Intriguing Owls, Exceptional Images and Insigt" by Stan Tekiela, pg. 22.) Another difference, an owl's eyes are tubular shaped, not round like ours. The added length in the eye from front to back increases the focal length, which means the image appearing on the retina is larger than on a round eye. This is like walking around with a built-in telephoto lens (Tekiela, 23).

40% of all owls have ear tufts. The tufts work to help conceal the bird by fragmenting the outline of its body...or by simulating the top of a broken tree branch. Researcher Denver Holt (founder of the Owl Research Institute) studied owls with ear tufts when they were in the presence of a dangerous predator such as a cat. The owls immediately raised their ear tufts and even constricted their body feathers to appear thinner and taller, mimicking a branch (Tekiela, 62---if you're looking for an interesting book on owls, Tekiela's book, "Intriguing Owls, Exceptional Images and Insight" is a fantastic book. It's packed with interesting facts like this, plus phenomenal photos. It's one of my favorite owl books.)

"Tiger Owl"--another nickname I had never heard of! It's easy to see where it comes from, though. The colors and stripes of the feathers on the owl's belly resemble a Bengal Tiger...or maybe it's called a Tiger Owl because it's so ferocious when it's hunting!

My son read "Walden," by Henry David Thoreau this summer, so when he was finished with it I picked it up to re-read it. When I came across the following passage (Chapter XV: Winter Animals), I knew the quote would eventually end up on the blog. With November and winter fast approaching, it fits our Great Horned Owl couple perfectly...

"For sounds in winter nights, and often in winter days, I heard the forlorn but melodious note of a hooting owl indefinitely far; such a sound as the frozen earth would yield if struck with a suitable plectrum, the very lingua vernacula of Walden Wood, and quite familiar to me at last, though I never saw the bird while it was making it. I seldom opened my door in a winter evening without hearing it; Hoo hoo hoo, hoorer, hoo, sounded sonorously, and the first three syllables accented somewhat like how der do; or sometimes hoo, hoo only."

Many versions of Walden are available online. If you don't have a copy of the book at hand but want to read this chapter, click here for a link to Wikisource.

Note: RAPTOR, Inc. is a non-profit organization committed to the preservation of birds of prey. RAPTOR stand for the Regional Association for the Protection and Treatment of Raptors. Members of RAPTOR, Inc. rehabilitate and care for injured birds of prey until they can be released back into the wild. Click here for RAPTOR, Inc.'s HackBack newsletter and to learn how to donate to the organization, volunteer, or sponsor a banded raptor.