Outdoors

Don’t underestimate the ferocity of the great horned owl

Posted Feb. 16, 2017, at 2:35 p.m.

I don’t know everything about birds. Sometimes I just have to fake it. For instance, I was recently asked if a great horned owl could take a cat.

No, I said to myself. Great horned owls only weigh about three pounds, give or take a few ounces. Cats weigh twice as much and more. Surely that would be too much for an owl to carry off.

Wrong.

Great horned owls are beastly. In a battle between an owl and an eagle, bet on the owl. Bald eagles can weigh up to 14 pounds. Their wings can spread to seven feet, which is two feet wider than the smaller owl can manage. But great horned owls are fierce. They begin nesting in midwinter, customarily taking over the nests of other large birds before those birds arrive in the spring. Occasionally, they commandeer eagle nests – nests that the eagles were planning to use. Scuffles follow. The owl usually prevails.

Great horned owls can carry up to four times their own weight. They will eat just about anything that moves, and even some things that don’t move. Carrion will suffice when the owl is hungry. Mostly, they’ll take rodents. Rabbits and hares are a prime target over much of their range. Fear of owls is one reason crows roost in big flocks this time of year.

The list of all species devoured by great horned owls is extensive. Opossums, muskrats, woodchucks, prairie dogs, and raccoons are on the list, though raccoons are rare. Great horned owls don’t think twice about snatching a skunk. They have a bad sense of smell and grab every skunk they can get. In fact, injured owls brought in for rehabilitation often smell strongly of skunk.

Great horned owls have been known to go after porcupines, and sometimes that doesn’t end well for the owl. There are documented cases of owl attacks on bobcats and fishers. Great horned owls take birds, including occasional ospreys, hawks, and other owls. They can take geese, which is impressive because a Canada goose can weigh up to 12 pounds.

Owls can do all this because they have strong, lethal talons. They can exert 28 pounds of pressure when squeezing sharp claws into a critter, quickly piercing organs and snapping the spine. They are silent on the attack and strike so hard that even larger animals are helpless before they know what hit them.

The contest between an owl and a peregrine falcon is less certain. Peregrines take their prey in flight by smashing into them. They will dive at a high rate of speed and strike smaller birds with their feet, usually stunning or killing the bird outright before the peregrine then grabs its limp body in midair. For larger birds, the falcon might try a glancing blow to a wing, disabling the bird.

They’ve been known to take prey as large as a sandhill crane. So an owl in the air would have its hands full, if it had hands.

But at night, owls reign supreme. They can snatch falcons off the nest or from cliff edge roosts. The predation is so severe that when falcons were being reintroduced in the eastern United States, including Maine, the first step for biologists was to survey for great horned owls in order to make sure there were none around.

Surveying for owls isn’t too hard. Since they tend to take over conspicuous nests, and they begin nesting so early, an aerial search may turn up a pair. More often, they can be found just by listening for mid-winter hooting. Great horned owl couples hoot a lot before egg-laying season begins. As with most raptors, female owls are bigger. But male owls have a larger voice box. Both owls hoot to each other, and his voice is lower.

All of this hooting activity should commence soon. In fact, other owl species will be joining the chorus presently. Expect more about hooting owls next week.

It’s no surprise that an owl this big and tough is widespread. It’s found throughout North America right up to the tree line in Canada, and down through much of South America all the way to Argentina. That encompasses a lot of different habitats. While mammals are the owls’ top prey, and birds are number two, owls of the desert dine on scorpions and consume many reptiles and snakes. Cottonmouths of the swamps and rattlesnakes of the prairie are on the menu.

So, yeah, they can take a cat.

Bob Duchesne serves as vice president of Maine Audubon’s Penobscot Valley Chapter. He developed the Maine Birding Trail, with information at mainebirdingtrail.com. He can be reached at duchesne@midmaine.com.

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