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Barred Owl Threat

Image of Barred Owl (Wikipedia)

Encroaching Competitor Adds to Spotted Owl's Struggle

The U.S. Fish and Wildlife Service has identified competition from barred owls as one of two main threats to the northern spotted owl’s continued survival (habitat loss is the other). We are conducting an experiment to test the effects of removing barred owls from certain areas of spotted owl habitat to see if it would benefit spotted owls. 

To date, the Barred Owl Removal Experiment has demonstrated success with reduced and declining populations of barred owls and indications of improvement in spotted owl apparent survival rates.  We have decided to continue the Experiment through August 2021 to allow us to validate the initial results.

This continuation is within the maximum duration (10 years) of barred owl removal set in the Final EIS and does not substantially change the proposed action.  In addition, there are no significant new circumstances or information and the estimated total number of barred owls to be removed remains within the number estimated in the Final EIS, simply spread over a longer period.

View study update.

  • Barred owls are native to eastern North America. It is believed they began expanding west of the Mississippi River around the turn of the 20th century. This could have been a natural range expansion or human-caused, or a combination of both. The most common theory is that the barred owl’s westward movement was caused by changes to the environment in the Great Plains as people increasingly settled there and dramatically altered the landscape. This may have removed natural barriers that previously inhibited the barred owl’s westward expansion.

    Barred owls now outnumber spotted owls in many portions of the latter’s range. Researchers have seen strong evidence that spotted owl population declines are more pronounced in areas where barred owls have moved into the spotted owl’s range. Declines are greatest where barred owls have been present the longest. The U.S. Fish and Wildlife Service is concerned that without barred owl population management, the spotted owl is likely to go extinct in some parts of its range.

    Barred owls are larger, more aggressive, and more adaptable than northern spotted owls. They displace spotted owls, disrupt their nesting, and compete with them for food. Researchers also have seen a few instances of barred owls interbreeding with or killing spotted owls. Because the spotted owl is already struggling due to its reduced habitat, the effect of the barred owl’s presence is an added stressor. An already vulnerable population has a much more difficult time withstanding dramatic changes in the ecosystem such as the encroachment of a competitor. A healthy population, on the other hand, has more flexibility to adapt to changes.

    The goal of this experiment is to test the feasibility of barred owl removal to determine whether it improves conditions for spotted owls on a small scale. We will remove barred owls on less than one twentieth of one percent of the range of the barred owl. If the experimental removal of barred owls results in improved spotted owl populations, we may consider proposing wider scale treatments as part of a barred owl management strategy. We would initiate a separate environmental review, with an extensive public review and comment process before making any such decision.


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