You don't have to be a birder to be fascinated with owls. In fact, owls have been worshipped and feared by many cultures for millennia, from the ancient Greeks and Romans to today's Harry Potter books. Because of their nocturnal habits, owls have long been associated with witchcraft, no doubt because we humans are almost helpless in the dark. Owls have been considered both wise and foolish, and harbingers of death and even the weather. The Tlingit Indians of southwest Alaska would rush into battle hooting like owls to strike fear into their enemies.
Depending on the classification system you happen to endorse, there are between 150 - 220 species of owls in the world, living on every continent except Antarctica, and ranging from alpine forests to the deserts. Most are nocturnal, with incredible adaptations to allow them to be efficient predators of the small mammals, insects, fish, and sometimes other birds that they consume.
All owls have keen hearing due to several interesting adaptations. Their ears are asymmetrical in both size and placement on the head. This gives them a triangulation effect to be able to pinpoint subtle sounds, like the footfall of a deer mouse walking on the snow. Also, the arrangement of the facial feathers into that classical disc-shaped face acts like a radar dish to funnel sounds to the ears.
The eyes of an owl are extremely large and in some species account for 5% of the body weight, and are extremely sensitive in low light situations. They are fixed in bony eye sockets, and because of this they cannot move their eyes, so must turn their head to see around them. Owls can turn their head a full 270 degrees. Almost, but not quite all the way around like some used to believe.
To round out their predatory prowess, owls are capable of quiet flight. With their broad wings and light bodies, they are capable of slow, moth-like flight, and because the edges of the flight feathers are soft they are very silent fliers. With their eyesight, hearing, and stealth mode, that aforementioned deer mouse doesn't have a chance.
In this part of the world, there are nine species of owls. The two species that most locals are aware of, birder or no, are the Barn Owl and the Great-horned Owl. These are our two largest owls and can be quite common. The Barn Owl gives a quite un-owl-like call — a high pitched screech — and interestingly, is in a separate family from the rest of the "true" owls. The ground below their roosts can be deeply littered with their pellets, the undigested hair and bones of their prey, regurgitated after every feeding. Farmers and vineyard owners often place Barn Owl nest boxes around the property for rodent control.
In the drier, eastern part of the county the two resident owls are Short-eared and Burrowing Owls. They both are ground nesting birds — in fact the Burrowing Owl nests underground in old squirrel holes. They both are active during the day, and both are considered species of concern because of habitat loss and the dangers of ground nesting with the introduction of cattle, and domestic dogs and cats.
My favorite owl has to be the Northern Pygmy Owl. This sparrow-sized, aggressive owl hunts other birds mostly at dawn and dusk, but it can be active during the day. The small passerine prey of this owl often "mobs" it, and it can be a way to find one roosting. In Pygmy Owl territory, a whistled imitation of its call can attract small birds, upset and vocalizing, trying to find and discourage their nemesis from the area.
Rounding out our county owl list are Long-eared Owl, Western Screech Owl, the very uncommon Northern Saw-whet Owl, and in darkly wooded and wet canyons, the Spotted Owl, the bane of loggers everywhere.
Because owls are often hard to see, it can be advantageous to learn their calls. An internet search will return many owl call sites, such as the Cornell Lab of Ornithology site. Enter the name of the owl for information about the species and a recording of its call.
