Living with wildlife: Owls attack from third dimension

By Gary Raham
Nature Writer and Illustrator

Back to Gardening Articles List

Being the relatively large terrestrial creatures that we are, we can often safely ignore the third dimension. Few dangers lurk above our heads, unless we're in a construction zone.

Mice, shrews or even something as large as a skunk ignore the third dimension at their peril. Daily, they risk the danger of being pierced by the talons of stealthy hunters like the great horned owl that swoops out of the sky on wings hushed by sound-deadening filaments at the tips of their flight feathers. Urban naturalists may want to study the third dimension on behalf of their pets, as cats and small dogs could find themselves unexpectedly airborne in unfriendly skies.

Great horned owls (Bubo virginianus) patrol Wellington now and then. Some years ago I saw our cat sitting outside on top of the doghouse looking up with intense concentration. I stepped to the doorway and followed her gaze. Perched majestically on top of the utility pole, a great horned owl looked back with a certain sinister gravitas. When I opened the door, the cat scooted inside. She was not used to being on the receiving end of such malevolent intentions.

Great horned owls fare pretty well in suburban habitats. Their series of four or five deliberate, resonant hoots let us know that something wild is out there in the trees. Males make the most noise, declaring territorial rights. Males hoot with a deeper pitch, though they are smaller than females. These owls may also hiss, bark, whistle and scream during various aggressive or courtship interactions and produce distinct clicking sounds when they snap their bills.

Males set up territories in late fall, and then proceed to dazzle a prospective female with bowing, some elegant feather fluffing and a flashy spread of wings. Males have also been known to resort to hopping around on the ground, snapping their bills with élan and bringing some good food to eat--a general pattern certainly recognizable to females of many species. When the lady's made her choice, the pair set off to steal a nest, quite often using the former residence of a red-tailed hawk. Great horns also have been known to use the nests of crows, herons and squirrels; take up residence in caves and on cliff ledges; or even nest on the ground.

Females lay one to six eggs beginning as early as February with a one- or two-day spacing between eggs. Females begin incubating eggs as soon as they are laid and males will relieve their mates now and then, allowing them to hunt. This early season child-rearing strategy appears to give great horns a head start on other bird species whose nestlings sometime fall prey to owls.

Great horns possess excellent hunting tools, including eyes that can see 10 times better than ours in daylight and 100 times better at night. Offset ears on either side of their heads provide stereoscopic reception, and wicked talons make them 3 pounds of flying nightmare for rabbits, snakes and rodents of all persuasions - not to mention grad students or other naturalists who might choose to poke around their nests. One researcher said, "I felt as if I was being hit with a sharp brick," when describing an owl attack after coming away with a badly torn shirt and bleeding neck.

He had forgotten that all-important third dimension.

The so-called "horns" that give this owl its name are actually feather tufts called plumicorns. They don't aid hearing at all but are instead owl "mood indicators" that can be flattened or extended as desired and may help provide the owl with a silhouette that appears less predator-like to potential prey.

When I was volunteering for the Rocky Mountain Raptor Program some years ago, I enjoyed seeing these amazing predators up close. Their eyes, as large as a human's and raptor intense, demand attention. They swivel their necks in ways that make mine hurt just watching them, but this ability provides them with an excellent 270-degree field of vision. Volunteering for the Rocky Mountain Raptor Program, by the way, can get you up close and personal with a variety of birds of prey. The program has a web site, www.rmrp.org, and just moved into new quarters on Vine Drive in Fort Collins. I also recently ran across a RMRP volunteer and blogger who is a fan of the great horned owl. Visit with him at featherweather.blogspot.com/2005/12/cool-birds-2-great-horned-owl.html.

Should someone wish to become an owl voyeur, Xcel Energy provides an owl cam stationed at the Valmont Power Station in Boulder. Go to birdcam.xcelenergy.com/dayinthelife_owl.asp and click on a time. The owl cam provides hourly looks at a nest frequented by owls.

While the great horned owl is mostly nocturnal, it will hunt by day--especially near dawn and dusk--as my cat discovered that day she paid attention to this amazing raptor peering at her from the third dimension. The great horned owls leave pellets in their wake stuffed with the bones and other hard remains of the many critters that failed to do so.