One late night recently when returning home from a business trip and driving across a remote stretch of highway near Grand Rapids, a large bird flew across the highway.
The headlights of the vehicle illuminated the bird and obscured its plumage coloration, but based on its size, it looked to be a great horned owl. Such a magnificent creature, owls are truly special birds.
If you were to ask any Minnesotan to name just one species of owl, I would bet most people would either say or describe “great horned owl.” Isn’t this the owl that first comes to your mind, or at least one that is large in body size with big yellow eyes and devilish-looking "horns" growing on top of its head?
The great horned owl is our most common Minnesota owl. Indeed, this large owl, though appearing smaller than the great gray owl, is heavier than the great gray. As well, the great horned owl is the only large owl with feathered ear tufts. Other smaller owls possess ear tufts too, such as the short-eared owl and screech owl. And no other owl has quite the same hoot as the great horned.
Most owls are nocturnal and all are birds of prey. Some, like short-eared owls, are daytime and twilight hunters. But for most species, dusk and night is the time for a shift-change at the raptor time clock.
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Replacing eagles, hawks and falcons as top avian predators of the daylight hours, owls are true masters of darkness and come equipped with adaptations unmatched in predatory birds.
Owls are perhaps one of the most unique and specialized birds I know of. Like most owls, barred owls hunt during the twilight and night hours. And like all other owls, their vision is extraordinarily acute.
On exceptionally dark nights, an owl’s pupils are at their largest, which in turn allows the maximum amount of light to enter into their eyes. Special light-sensitive cells contribute to an owl's amazing ability to see in the dark.
But unlike other animals, owls’ eyes are immobile. Owls cannot move their eyes. However, they can move their heads nearly completely around, about 270 degrees. This is possible because of an owl’s long neck and high number of vertebra. For comparison, we have just seven to the owl’s 14.
While owls certainly rely on vision to locate prey, sensitive hearing and pronounced facial disks help to pinpoint prey location and to reflect sounds of scurrying animals many dozens of feet away too. As well, soft feathers provide silent flight for capturing prey undetected while long and sharp talons on each foot serve as deadly weapons to hold prey securely once caught.
Twelve species of owls occur in Minnesota: great horned, long-eared, short-eared, barred, burrowing, great gray, northern hawk, eastern screech, northern saw-whet, boreal, snowy and barn owl.
Some species, like great gray, northern hawk, and snowy owls, occurs more frequently during some years than at other times. Other owls, like barn and burrowing owls, have a limited range in Minnesota.
Minnesota owls hunt prey from as small as insects and frogs to as large as rabbits and skunks. Small prey, such as mice and voles, are swallowed whole, bones and all. Larger prey is consumed in chunks that are torn from the carcass by using their hooked beaks.
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And since an owl's digestive system cannot process bones and fur, these parts are regurgitated in scat-like pellet form that can often be found beneath favorite roosting sites and nest trees. These owl pellets provide the interested observer an opportunity to learn what the bird was feeding on and where it may live.
And so it is, that these birds of prey — great horned owls and owls in general — alighting on tree limbs while surveying the forest and fields for prey, are all about us as we get out and enjoy the great outdoors.
Blane Klemek is a Minnesota DNR wildlife manager. He can be reached at bklemek@yahoo.com.
The Trust Project
