Northern Spotted Owl Habitat in British Columbia
photo from http://www.owlpages.com/species/strix/occidentalis/Default.htm
Introduction and conceptual outline
The Northern Spotted Owl is an endangered species that will likely be extirpated from Canada in the near future. The species is associated with the old-growth forests of the Pacific Northwest from northern California to southwestern British Columbia. However, this project will focus only on the B.C. habitat.
The spotted owl has received much attention recently in B.C. because of the rapid decline in population. From 1992 to 2001, the Population Assessment of the Northern Spotted Owl in British Columbia 1992-2001 (1) found that the population of its survey area fell by 49 percent. This same assessment estimated that there are fewer than 50 breeding pairs in the province. This drastic decline in population is due mainly to the logging of their habitat. Spotted owls prefer old-growth forests, which also contain the most commercially valuable timber.
photo from Wilderness Committee
This project intends to identify suitable habitat for spotted owls, which I predict will be small, fragmented areas. From this we can determine if there are contiguous areas large enough to support several pairs of owls. The activity area for a pair of owls is approximately 3321 hectares, while the overlap of ranges between pairs is from one to 47 percent (2). The area of suitable habitat already protected in parks and important areas that need to be protected can be determined as well.

To identify suitable areas, several criteria were established. Forest type (old forest, young forest, and selectively logged forest), biogeoclimatic zones, and elevation are important factors. While the owls prefer old-growth forest, they have been found in selectively logged forest with characteristics similar to those of old-growth (2), and younger forest stands (3). Their associated biogeoclimatic zones are the Coastal Western Hemlock (CWH) and the Interior Douglas Fir (IDF) zones, and they have been found at elevations up to 1370 meters (2). Roads and railroads, fresh water, urban areas, agricultural areas, recently burned forest, recently logged forest, snow and glaciers, and barren surfaces all constrain the habitat since they cannot live in lakes, in cities, on glaciers, etc. However, distances from urban areas, agriculture, and roads and railroads were used as factors because it is unlikely that the owls will live right on the edge of these boundaries due to the disturbances.

If the government of B.C. and logging companies that hold licenses in the suitable habitat were willing to protect the spotted owls and their associated ecosystem, this project would have policy implications and could be used to determine sites to protect from logging and other human disturbance.

The results could also be useful for a reintroduction program by helping to determine suitable areas to reintroduce the owls.