Nature on Trail: Barred and Spotted Owls

By Sylvia Feder

You are walking through a needle-carpeted trail in an old-growth forest in Olympic National Park when a slight movement catches your eye. Perched above you, camouflaged against a backdrop of branches, is a beautifully patterned owl, about the size of a guinea pig, watching you curiously with dark round eyes.

Ten years ago, the bird most likely to be watching you would have been a northern spotted owl, the living symbol of mature conifer forests. Not so today. In fact, there is a battle being waged in old growth forests across the Pacific Northwest, and the spotted owl is, once again, at the heart of the conflict.

Long-time Washingtonians will remember that the spotted owl leapt from relative obscurity to the front pages when it was listed as a threatened species in 1990. More than a description, the term “threatened” was a formal designation under the federal Endangered Species Act, mandating action to help preserve the species. As a result, over the next few years, logging in old growth forests - the owl’s natural habitat - was greatly curtailed. Many Northwest residents have vivid memories of bitter protests and dying logging towns.

The Northwest Forest Plan, the legislation addressing the needs of old-growth forests, was developed to protect many more species than just the northern spotted owl. Nevertheless, the owl remained the symbol for those on both sides of the issue.

With large tracts of old growth forest protected from logging, one might assume that the spotted owl populations would have increased or at least stabilize. Unfortunately, recent studies have shown that the populations are continuing to fall. Speculators have proposed any number of reasons: decreasing habitat in spite of the legislation, climate change altering the ecology of the old forests, a genetic bottleneck restricting diversity. Valid as these reasons may be, the effect of another culprit may be more important.

Today, when you are walking on that trail in the Olympics, the owl that caught your eye is most likely to be a barred owl, not a northern spotted. Barred owls are non-native invaders from the east coast. They are a forest dwelling species, so historically the Great Plains prevented their dispersal west. Some scientists think that the warming climate allowed them to extend their range north into Canada and then move westward through Canada’s forests.

The barred owl is closely related to the spotted - slightly larger, but otherwise very similar at a first glance. A closer look reveals a different pattern of spots and bars and a good field guide is your best bet for telling the two apart. Unfortunately for the spotted owl, the barred owl turns out to be versatile and aggressive competitor. Living in the same terrain as the spotted owl, it eats a wider variety of food, breeds more frequently, produces more young, and on occasion even preys on its smaller cousin. When barred owls invades an area populated by spotted owls, the spotted generally disappears. Some studies in the Olympics suggest that their numbers may be decreasing by three or four percent per year.

This owl competition leaves biologists and wildlife managers in a difficult position. Should they allow nature to take its course, with the possible extermination of the spotted owl, or should they intervene? Studies and recommendations will undoubtedly be forthcoming. In the meantime, observant hikers have a front row seat to this ecological drama unfolding in our old growth forests.

This article was originally published in the July+August 2010 issue of Washington Trails magazine.