By Terry W. Johnson
Now that the Peach State is in the icy grip of winter, it’s hard to imagine that a handful of birds are actually nesting. One of these is the great horned owl, and it may be sitting atop a nest in your backyard right now.
There was a time in the not too distant past when great horned owls nested almost exclusively in areas little frequented by man. However, over the past several decades as much of our countryside has been blanketed by development, great horned owls have been nesting in increasing numbers in these newly created urban and suburban settings. Today you are as likely to find great horned owls nesting within sight of high-rise buildings in Atlanta or in wooded residential developments on the outskirts of Albany or Brunswick as you would in Big Lazer Creek Wildlife Management Area.
I have seen great horned owl nests in places such as the front yard of a suburban home in Sumter County, the wooded backyard of a residence in Forsyth and beside a busy street and construction site on Sea Island.
Great horned owls begin looking for nest sites as early as September. The owl doesn’t build its own nest. Instead, it commandeers the nests of hawks, crows, ospreys, squirrels and even bald eagles. However, the nests of red-tailed hawks seem to be preferred. These nests are often 40-70 feet above the ground in the crotch of a tree. Once a pair of great horned owls decides to take up housekeeping, they may use the nest for three to four years and then, for no apparent reason, abandon it.
Although great horned owls are excellent parents, home repair is not their strong suit. In fact, they do little if anything to repair a nest site. Consequently, it is not uncommon for their eggs or young to fall through gaping holes in a dilapidated nest.
If a pair of great horned owls nests in your neighborhood, it is unlikely another pair is nesting nearby. This is because the owls will vigorously defend their nesting territory from other owls and hawks. These nesting territories can range in size from one-third to 2 square miles.
The nuances of the great horned owl’s courtship remain shrouded in mystery. However, we do know that in Georgia it typically takes place in December and early January. For this reason, this is the best time for you to venture into your backyard at night and listen for the birds’ eerie, muffled love calls and their more typical resonant, low-pitched hoo hoo hoooo hoo hoo. (Listen to their calls.)
In this neck of the woods, female great horned owls usually lay only two eggs. If they are destroyed, she will rarely nest again that season. The second egg in the clutch is laid some three days after the first. However, unlike most birds, which begin incubation only after an entire clutch of eggs is laid, great horned owls begin incubation immediately after the first egg appears. Consequently, one owlet hatches well before its nest mate. Thus, a great horned owl nest often contains one owlet that is much bigger than its later-hatching sister or brother.
Nesting occurs in the dead of winter. It is hard to believe that the birds can nest in weather as cold as it has been this year. However, as bone chilling as temperatures have been, nesting great horned owls have coped with them easily. In fact, great horned owls are so well adapted to nesting in the cold they have been found nesting in temperatures that dipped below minus-20 degrees Fahrenheit.
As you might expect, however, winter is harsh on the birds’ eggs and young. Eggs are incubated solely by the female. Since the eggs can freeze, she spends little time away from them during incubation. In the case of the owlets, they have been found trying to keep warm burying themselves beneath tufts of hair from the prey brought to them as food.
After the eggs hatch, both parents vigorously defend their young and provide them with a steady supply of food. Young owls enter the world about the size of baby chickens and grow rapidly. One biologist found 18 pounds of birds, mammals and fish surrounding two 4-day-old hatchlings. A typical diet for the growing youngsters might include rabbits, mice, hawks, crows, fish and even skunks. In only four weeks, the young are nearly full grown, although they don’t fly well until they are 3 months old.
As I was saying earlier, young often fall from a nest. Remarkably, these unfortunate owlets will actually climb 40 or more feet back up to the nest. If they can’t make the arduous climb back to their nest, their parents will continue to feed them on the ground.
Great horned owls swallow their prey whole. Some of these food items are quite large. In one instance, an adult great horned owl was able to swallow a 1-pound muskrat in one gulp! Great horned owls regurgitate much of what they can’t digest in masses called owl pellets.
If you find a great horned owl nesting in your neighborhood, be on the lookout for these pellets. They are grayish-brown to black and measure 3-4 inches long and about an inch-and-a-half in diameter. If you tear apart a pellet, you will get a pretty good idea what the owl that left it fed on. The pellets commonly contain a mix of bones, hair, teeth, claws and feathers.
The next time you step out your backdoor on a bitterly cold, clear winter night, ponder on the possibility that great horned owls may be nesting nearby. It is comforting to know that the warm sanctuary of your home is but a few steps away. Realizing that owls have no way of escaping the deadly cold, you can’t help but admire the fact that these magnificent aerial predators are up to taking the worst that winter has to offer.
Terry Johnson is a former Nongame program manager with the Wildlife Resources Division, a backyard wildlife expert, and executive director of TERN, the friends group for Wildlife Resources' Nongame Conservation Section. Terry’s column is a regular Georgia Wild feature.