Spotting the Spotted Owl

Deep in the forests of the Pacific Northwest, lives a nocturnal carnivore of unparalleled repute. Some say they’ve seen it swoop down on its victims in the dead of night and feast on the bodies among the branches of knotted, old trees. Others say its haunting call can be heard from a mile away. The mere mention of the creature’s name brings shudders to loggers and some local inhabitants. Fear over its existence has incited rallies, garnered the attention of three government agencies, and caused people to tie themselves to trees.

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Flying squirrels and wood rats are a spotted owl's favorite prey. (Photograph courtesy Jerry Mires)
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To scientists this animal is known as Strix occidentalis caurina, but it is commonly referred to as the northern spotted owl. For more than ten years environmental groups and logging corporations spent millions of dollars in attempts to control the fate of the bird’s old-growth forest habitat. Hardly a week went by in the late 1980s where there wasn’t a story about a protest rally attempting to save the owl or news of lawsuits being filed to stop the harvest of the owl’s habitat.

A northern spotted owl at home in the old-growth forests of the Pacific Northwest. As part of the plan to protect the spotted owl, biologists and land managers are using satellites to map potential habitat. (Photograph courtesy Janice Reid)
At the end of the decade the U.S. Fish and Wildlife Service put the owl on the Federal Threatened Species List, and the federal government devised a strategy to conserve the old-growth forests in western Oregon, Washington, and Northern California. While these government actions quelled the conflict between loggers and environmentalists, they created a whole new set of challenges for the scientists studying the owl’s habitat. The problem was that no one in the state or federal governments had a way to determine how many birds or how much old-growth forest existed in an area as vast as that specified by the government plan. For four years scientists from three government agencies toiled over a number of approaches.

Earlier this year a method to monitor the owls was finally decided on. With the help of Landsat 5 and the newly-launched Landsat 7, researchers plan to locate areas where owls are likely to live. They will then use this information, along with ground surveys, to map out the owl’s habitat and create a method for assessing the health of the owl population in the Pacific Northwest. Whether this strategy will succeed remains to be seen.

ornamentnext The Spotted Owl’s Checkered Past

The data used in this study are available in one or more of NASA's Earth Science Data Centers.

Because of the link between spotted owls and undisturbed forest, the threatened birds have been caught up in the conflict between environmentalists and the timber industry. (Photograph courtesy Sierra Club)