Are Barred Owls and Northern Spotted Owls Fighting Over the Same Territory?

Barred OwlPhoto: TerrenBarred Owl

Barred owls, also famous as hoot owls, are best described as an opportunistic predator. As many as 160 types of owls exist all around the world, among them the typically large, about 3.5 feet tall barred owls, which are widely distributed throughout North America.

In the last 30 years, these owls have expanded their range into the Pacific Northwest, which is also the range of their close relative, the northern spotted owl. Based on the survey methods developed for barred owls, a team of scientists has determined that this expansion has resulted in a lack of critical resources for these species. The barred owls are competing with the spotted owls, sharing the same environment and habitat. Is there any relationship between the increasing number of barred owls and the dwindling population of northern spotted owls? Well, research is still going on.

Northern Spotted OwlPhoto: Hollingsworth, John and KarenNorthern spotted owl

A study was published in the Journal of Wildlife Management, April 2011 issue, whose purpose it was to determine the degree to which barred owls were going undetected during calling surveys directed at spotted owls.

David Wiens, a USGS scientist and lead author of the study says: “We wanted to study the competitive interactions between these two owl species, but before we could do that, we needed to be certain we were using survey methods that worked equally well for both species. By using methods specifically designed for barred owls, we were able to more accurately assess the occurrence and distribution of barred owls over an extensive forested landscape.”

Barred OwlPhoto: Frank KovalchekBarred Owl

David Wiens and his co-authors are still working on this project, which is funded by the U.S. Fish and Wildlife Service, National Park Service, U.S. Forest Service, Bureau of Land Management, Oregon State Department of Forestry, Oregon State University and Boise State University. Eric Forsman, U.S. Forest Service scientist and co-author of the study, said: “Habitat requirements are more critical than ever when you have two species that are closely related, occur in the same areas, and likely are competing for food and space.”

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