I first heard the owl in the wee hours before dawn two years ago, in early October. I was in our courtyard, checking a moth sheet at that early hour. I’d never heard an owl before, but it was the unmistakable classic call: who, who – hoo, hoo, hoo in a clear baritone, seemingly right over my shoulder. In a moment, a lighter pitch repeated the call from further away.
Admittedly, it gave me pause; the loud one was on the roof of our house, seemingly just over my shoulder – I’m sure it was watching me. I quietly but swiftly crept back indoors. I later texted a birder friend who confirmed I was now the proud landowner of a pair of great horned owls (Bubo viginianus).
Female great horned owls are larger than the male, but males have the deeper sounding voice; great horned owls are the more vocal of the owl species.
As the sky got lighter, and I got braver, I grabbed my camera and long lens and was eventually rewarded with seeing the pair. Just before daylight, they swooped to the then largest tree on our property: the pre-freeze-killed Norfolk Pine. What a sight!
This summer, there were three. I watched them in the early morning, perched across the resaca on snags of a dead tree or flying into the top of a palm tree close to our house. The third owl was a juvenile, possibly about five months old by July. Juvenile great horned owls stay with their parents for six to nine months.
By mid-September, the juvie seemed to be beginning its familial separation. We happened upon it a couple of mornings, sitting by itself on the retaining wall, overlooking the resaca. We’ve since read that a parent would probably have been nearby, observing. The young one let us get quite close before taking off.
One morning, it was squatting in the shallow water between the resaca bank and the dock. I slowly got onto the dock and was allowed to study the bird and take photos while it sat eyeing me and turning its head, scanning all around. Eventually it lifted off and flew to a tree branch on the opposite bank of the resaca.
The great horned owl species is highly adaptable; they live across most of the Americas, from Alaska and Canada to Central and South America. They are permanent residents in their location; only those in the extreme north migrate. An average territory for a great horned owl is about two to five square miles and can be maintained by the same pair for five to eight years, according to different sources.
Common in Texas, great horned owls are the largest of the 11 owl species in the state at two feet tall and a wingspan to five feet, yet they weigh only about three pounds. They are one of the earliest egg-laying birds in North America. In Texas, breeding can begin in December, owlets born by February, and first flight attempts after six weeks. By October or November, young owls are fully independent and leave their parent’s home range to find their own hunting territory.
Great horned owls are fierce nocturnal carnivorous predators with some of the most diverse and well-balanced diets of any north American owl. Their prey includes about 90 percent mammals and 10 percent birds: skunks, opossum, rabbits, bats, rats, ground squirrels and mice, other birds, hawks, smaller owls and waterfowl including coots and ducks. They also eat insects, scorpions, snakes and other reptiles. Those living near water sources typically eat more amphibians and fish. They swallow small prey whole, larger prey is carried to a perch or nest and torn apart. They can carry prey weighing up to 15 pounds. Their powerful talons enable them to sever the spine of large prey; they are a danger to even osprey and Peregrine falcons. Their clenched talons require a force of 28 pound to open, according to All About Birds.
Although great horned owls are nocturnal, they can often be found hunting in the daytime, mostly on cloudy days. Adults may continue to hunt in the daylight when they are feeding their young. Juveniles will continue to hunt for prey after sunup if they haven’t been all that successful during the night. The young ones are more likely than adults to be found hunting on the ground.
The great horned owls’ iconic features
The horns, although iconic descriptors of the great horned owl, are a misnomer, they are actually feathered tufts called plumicorns and begin to appear when the owlet is around three weeks old. About 50 species of owls have plumicorns. The owls can make them stand straight up or flatten down on their head.
Plumicorns are not ears, the great horned owls’ ears are on either side of their head, underneath their feathers. It is theorized that plumicorns may mimic a mammal and aid the owl in appearing more frightening to mammal predators, or they may be a camouflage function in making the owl appear to be a broken branch.
Great horned owls have bright yellow cat-like eyes. The eyes do not move, but owls can turn their head up to 270 degrees to see in different directions.
They have excellent hearing and vision and excellent night vision because of the numerous rod cells in their eyes. Their vision is triggered by movement; they can spot a large target, such as a rabbit from nearly two miles away. They can hear sounds ten miles away.
The silence of the flight
In flight, great horned owls are nearly silent because they have very soft feathers that muffle the sounds their wings make when flying, according to Animals.howstuffworks.com. Owl feathers have velvety fringe on the trailing edge which streamlines airflow and absorbs the sound produced. This stealth allows them to swoop down silently and grab prey in their strong talons. They can fly up to 40 miles per hour. Owls’ wings are large compared to their bodies, and this lets them fly more slowly and with little flapping.
Young owls are covered with much of their adult plumage after two or three months, but it can take a couple more months to develop fully. An owl’s color varies by location and is designed to be camouflaged to their surroundings. Their brown, black, white and gray streaked plumage is darker in humid areas where they are more dark-brownish than in drier zones where they are a lighter shade.
Owls with large territories may spend each season in a different part of their territory. I have wondered if our great horned owls travel around. I check a moth sheet most mornings in the dark hours before dawn, when night temperatures are above 70 degrees Fahrenheit. I’ll hear the owls for several mornings in a row and then not for several weeks. When they’re overhead, they move around on their silent flights, calling to each other from different positions, who-hoo-ing back and forth. I now welcome their conversations, feeling safer in the dark when they’re chatty. My occasional hellos don’t bother them.
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These websites were helpful in writing this article:
featheredphotography.com/blog, willyswilderness.org, visitbigsky.com, birdfeederhub.com, animals.howstuffworkd.com, birdfact.com, wildliferesponse.org, allaboutbirds.org