The U.S. Geological Survey Oregon Cooperative Fish and Wildlife Research Unit led an effort to examine the status and trends of northern spotted owl populations throughout their range from 1985-2013 as well as the factors that affect the species' demographic rates. The resulting paper titled "The effects of habitat, climate and barred owls on long-term demography of northern spotted owls," was published in The Condor: Ornithological Applications. This research is part of the Interagency Northwest Forest Plan Monitoring Program supported by 10 federal agencies. This particular study was funded by the USDA Forest Service, Pacific Northwest and Pacific Southwest Regions, and Bureau of Land Management. A new U.S. Forest Service, Pacific Northwest Research Station website promotes awareness of the research.

The northern spotted owl was listed as federally threatened by the U.S. Fish and Wildlife Service in 1990 principally because of declines in its old growth forest habitat throughout the Pacific Northwest. In 1994, the Northwest Forest Plan (NWFP) was developed and implemented to conserve late-successional forest resources on federal lands to aid conservation of the spotted owl and other old growth forest dependent species. At that time, a long-term effectiveness monitoring program was developed to monitor the status of the spotted owl and through regular evaluation of the monitoring data, determine whether the NWFP was aiding in the species' recovery.

The newly released research reports on the effort to evaluate the status and trends in spotted owl demographic rates on 11 study areas across the species' range from 1985-2013. Researchers also examined the relationships between owl demographic parameters and the amount of suitable habitat, variation in local weather and regional climate, and competition with barred owls. Each year on each study area, field crews conducted surveys and determined whether historical territories were occupied by spotted owls and whether barred owls were also present on these spotted owl territories. Field crews also determined yearly survival and reproductive success of spotted owls by monitoring banded territorial individuals on each study area.

According to the research, northern spotted owl populations are declining in all parts of their range in the Pacific Northwest. Based on data from 11 study areas across Washington, Oregon and northern California, a rangewide decline of nearly 4 percent per year was estimated from 1985 to 2013. Researchers found evidence that the invasive barred owl is playing a role in the continued decline of spotted owls, although habitat loss and climate variation were also important in some parts of the species' range. Barred owls compete with spotted owls for space, food and habitat.

The paper is authored by Katie M. Dugger, USGS, Oregon Cooperative Fish and Wildlife Research Unit, Oregon State University Department of Fisheries and Wildlife; Eric D. Forsman, USDA Forest Service, Pacific Northwest Research Station; Alan B. Franklin, USDA APHIS National Wildlife Research Center; Raymond Davis, USDA Forest Service, Pacific Northwest Region, and 33 others.

The ONB features articles from Cooperative Fish and Wildlife Research Units across the country. Working with key cooperators, including WMI, Units are leading exciting, new fish and wildlife research projects that we believe our readers will appreciate reading about. This article was written by Katie Dugger, Assistant Unit Leader Ecology at the USGS Oregon Cooperative Fish and Wildlife Research Unit at Oregon State University.