Night Owls

The changing season means that beloved migrating birds like the Swainson’s thrush and the rufous hummingbird have left for the winter. But in the early dusks and long nights of winter, listen for the hoot of the great horned owl. You may also hear the western screech owl, hooting in the rhythm of a ball that bounces faster as it loses momentum.

The great horned owl, the western screech owl, the barn owl, and the barred owl are all common species that nest in the islands. The saw whet owl migrates through in the autumn, and the the long-eared owl and short-eared owl are also seen here.

The western screech owl incubates and hatches its eggs in sequence, so the young in the nest are a variety of ages and sizes. If food is scarce, only the first few eggs survive.

Barbara Jensen of the San Juan Audubon Society said that great horned owls, the largest local owls, are fearless hunters known to “whack people on the head” for getting too close to their nests. They eat not only mice and rabbits but also small dogs and cats.

The barred owl, another large bird (about 20”), has recently been expanding its range in the San Juans. Its habitat somewhat overlaps that of the spotted owl, which it preys upon. “It may be the final straw to spotted owls,” said Jensen. The barred owl emits a variety of barking sounds that on a misty night might lead one to imagine the Hound of the Baskervilles is loose in the woods.

Serena Lockwood, senior rehabilitator at Wolf Hollow Wildlife Rehabilitation Center, said that barn owls are more frequently seen in the islands nowadays. The barn owl is one of the most distinctive-looking species, with its heart-shaped white face. Lockwood said the short-eared owl is sometimes seen on short winter afternoons, “quartering” back and forth over the fields at American Camp, looking for mice.

Owls are remarkably adapted to hunting. Many that hunt at night have one ear higher than the other, so they can pinpoint their prey’s exact position. Jensen said that owls’ eyes have also evolved for efficient hunting: one pupil can dilate while the other remains constricted, allowing greater depth of focus. The leading edge of an owl wing looks like a comb, with tooth-like feathers that break up the airflow. This lets the bird swoop silently down on its unsuspecting prey.

Lockwood said cars pose one of the major dangers to owls, particularly smaller species like the saw-whet, as they hunt near open roads, and especially near just-mown fields where they have a better bird’s-eye view of mice and voles. On October 9th a barred owl that had been hit by a car was sent from Lopez to Wolf Hollow. Sadly, its condition worsened and it was clearly suffering, so it had to be anesthetized.

Lockwood said that drivers might help reduce the rate of owl/auto collisions just by becoming more aware of the fact that owls are out hunting in the evening.

To learn more about owls and other birds, visit the reference section of your library and dive into the massive 18-volume Birds of North America, which describes some 700 species in exhaustive detail. The San Juan Audubon Society generously purchased three of these sets, at about $3,000 each, for the Lopez, San Juan, and Orcas libraries. The great horned owl is #372 in Volume 10; the barred owl is #508, Volume 13. The index will guide you to others.

To hear hundreds of different bird songs and learn about birds and other wildlife, check out enature.com, sponsored by the National Wildlife Federation.

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