Territorial species, such as the spotted owl (Strix occidentalis), are predicted to follow an ideal despotic distribution. However, debate exists on whether wild populations actually meet the assumptions of an ideal distribution, such as perfect perceptual abilities (i.e., the ability to recognize high- and low-quality sites without error). Because this hypothesis has important life history ramifications for spotted owls, we investigated whether occupancy rates of California spotted owl (S. o. occidentalis) territories in the San Bernardino Mountains of southern California positively correlated with a qualitative "potential fitness" (denoted by λpf) estimated from survival and reproduction of territorial owls. Spotted owls in our study tended to occupy territories with the highest λpf, supporting the assumption of ideal perceptual abilities within this population. However, this relationship was noisy, and we suggest that some individuals do not assess site quality accurately because of perceptual limitations, prey dynamics, and large territory sizes. Furthermore, dispersal processes, high survival rates, and long life spans of spotted owls may be other key factors preventing some individuals from selecting sites of the highest quality and, consequently, our ability to precisely estimate λpf.
Bibliographical noteFunding Information:
We thank our many field assistants. We also thank personnel of the San Bernardino National Forest and Big Bear Ranger District for their cooperation and assistance during this study. G. Gould, J. Palmer, J. Verner, D. Solis, and J. Robinson provided additional support. The California Department of Fish and Game, California Department of Natural Resources, Southern California Edison, Region 5 USDA Forest Service (contract #FS/53–91S8-00-EC14 to R.J.G.), Pacific Southwest Forest and Range Experiment Station, Snow Summit Mountain Resort, Big Bear Mountain Resort, Salad King, Inc., and the University of Minnesota provided funding for this project. R. Ydenberg and two anonymous reviewers provided comments that greatly improved the quality of the manuscript.
- California spotted owls
- Ideal despotic distribution
- Strix occidentalis occidentalis
- Territory occupancy