One group of birds simultaneously fascinates while remaining nearly unknown in practice: the owls. Owls are not uncommon in Marin. Many neighborhoods are home to great horned owls, screech and barn owls are widespread in the appropriate habitat and several additional species are scattered throughout the county in small numbers, including spotted, saw-whet, short-eared and burrowing owls. It is not surprising that they intrigue us: Owls are fearsome hunters, incredible watchers and listeners in the night and beings that exist in what seems like another world, the dark and shadowy realm after the sun goes down.
The most common of our local owls — by a wide margin — is the great horned owl. This is the owl that makes the classic and distinctive hooting call we often think of when we think of owls, a stuttering “hoo-HOOO-HOOO-hoo” in variable patterns. You will often hear single birds declaring their territories in this way, but great horned owls are also one of the minority of birds that sing duets, with paired male and female birds exchanging hoots as they reinforce their pair bond, male voices lower and female voices higher. You can already hear great horns duetting in the evenings as they make an early start to their long nesting season: It takes some seven months from the laying of a great horned egg until the full independence of their young.
This is largely the consequence of their size: Great horned owls are the largest owls in North America by weight. They are imposing creatures: well over 2 feet in height, with a wingspan of over 4 feet. Great horns are easily recognized by their overall large dimensions and prominent “ear tufts.” Great horned owls punch above their substantial weight class in the wide diversity of their prey. While they will eat insects, small rodents and songbirds, they have also been recorded killing and eating skunks, porcupines, great blue herons, bald eagles and other adult great horned owls. These are the fiercest hunters in all the world of birds, and they are calling outside your window.
But we do have other owls as well. In broadleaf oak woodlands, we can encounter western screech-owls, a kind of mini horned owl that stands about 9 inches tall and weighs about a third of a pound. While their territorial calls bear some broad resemblance to the hooting of the great horns, they are both higher pitched and follow a distinctive “bouncing ball” pattern, a trill that starts out slowly before accelerating and then abruptly ending. Despite their name, our screech owls do not screech: They are close relatives of the eastern screech owl, which has been known to screech when its nest was being invaded by an early ornithologist. Ours just bounces.
If you do hear screeches in the night, they most likely belong to a barn owl. Barn owls are the most distinctive of our owls and belong to an entirely different lineage than all our other species. This is reflected both in their voices and in their unique appearance: largely white, with tawny highlights, featuring a flat “moon-shaped” face and an entire lack of ear tufts. Barn owls are open country hunters: Look for them on the edges of wetlands, agricultural areas and open fields, where they focus on hunting small, nocturnal rodents including rats, gophers and voles.
How can you see owls? One shortcut if you hear barn or screech owls around your home is to install an owl box, a larger type of bird house intended just for them. (Great horned owls are too big for houses and instead take over nests constructed by weaker creatures like ravens or red-tailed hawks.) Visiting open fields at dusk near local wetlands such as at Las Gallinas in San Rafael or Hamilton in Novato are good places to look for barn owls, as well as crepuscular species like burrowing and short-eared owls. But the easiest place to start is with great horned owls, which are present in most neighborhoods. Great horns are not hard to find, but require a change from our normal human habits: Turn down your inside sounds and listen to the evening out of doors. And when you hear the fearsome hooting from the cold January trees, shed the cozy comfort of your home and look for the taloned hunters calling in the night.
Jack Gedney’s On the Wing runs every other Monday. He is a co-owner of Wild Birds Unlimited in Novato and author of “The Private Lives of Public Birds.” You can reach him at jack@natureinnovato.com.
