Nesting season has begun. Birds of prey take a long time to fledge young, so their breeding season starts early. For example, great horned owls incubate their eggs for five weeks and the young do not take their first flight for another seven or eight weeks. Owls are courting now, accomplished mostly by vocalizations. Now is a great time to go owling.

Let’s consider the three most common owls in the state. We’ll cover their distinctive calls as well as their morphology, diet and habitat preferences.

Barred owls are common residents of woodlands, particularly around lake shores and swamps. These birds are gray with distinctive vertical black and white lines on the underside. Barred owls have large, brown eyes; all the other owls in the state have yellow eyes.

Barred owls are active at night and twilight. They are heard far more often than they are seen. The booming call of the barred owl has been described as “Who cooks for you? Who cooks for you-all?” Once you have heard the call, it becomes instantly recognizable.

Barred owls have a fairly broad diet. Small mammals like mice, voles and squirrels compose much of their diet, although foxes, birds up to the size of belted kingfishers, turtles, and even insects may be taken.

Great horned owls are perhaps nearly as common as barred owls in Maine. Unlike a barred owl, a great horned owl has two tufts of feathers on the top of its head that form the “horns.” With a wingspread up to 5 feet, these are impressive birds. The plumage is generally brown with some white feathers on the throat and cross-barred markings on the breast.

Capable of flying on silent wings and equipped with massive talons, great horned owls are efficient predators. Like the barred owl, great horned owls hunt mainly at night and at dawn and dusk. These birds can kill birds as large as pheasants, red-tailed hawks and barred owls, and mammals as large as mink and domestic cats.

The call of the great horned owl is a five- or six-note call, consisting of resounding hoots in the following cadence: hoot hoot-hoot hoot hoot.

The last of our common owls is the small northern saw-whet owl. Only eight inches long, saw-whet owls are endearing little predators. They feed primarily on mice, young squirrels, chipmunks and small songbirds.

The common name of this owl presumably comes from one of its calls that can be likened to the sound that is made when a mill saw is sharpened or whetted. The typical call is a series of monotonous whistles that seem to go on forever.

Saw-whet owls are birds of dense forests, especially coniferous forests. These owls are strictly nocturnal.

An owl prowl may well yield all three of these owls by aural identification. All of these owls will respond to imitations of their calls. You might enjoy driving some back roads after dark, stopping periodically to listen for the sounds of owl courtship.

The eastern screech-owl is a common bird throughout the eastern United States to our south but is quite rare in Maine. The Maine Bird Records Committee recognizes only four records for the state, all from the central part.

Eastern screech-owls give two distinctive calls. One is a long, tremulous trill, and the second is a whinny string of descending notes. Evan Glynn, Josh Fecteau, Andy Aldrich and Kevin Couture heard an eastern screech-owl in York on March 22. They were able to get a recording to confirm the record – a very nice discovery!

To prepare yourself in advance of an owl prowl, I recommend visiting the Cornell Laboratory of Ornithology’s website, allaboutbirds.org. You can search for any species of North American bird. The information will include several sound recordings.

Herb Wilson teaches ornithology and other biology courses at Colby College. He welcomes reader comments and questions at:

whwilson@colby.edu