Recovery Plan for the Northern Spotted Owl - DRAFT

II.A. Natural History of theNorthern Spotted Owl*1. Introduction2. Natural HistoryDescriptionThe northern spotted owl (Strix occilentalis caurina) is one of the most studiedand best known owls in the world. The research effort on this subspeciesrivals that on some European owls (Southern 1970, Saurola 1989, Nero et al.1987). This degree of scientific attention is the result of this owl's associationwith late seral stage conifer forest of high commercial value in the PacificNorthwest (Forsman et al. 1984). The bird is the topic of vigorous debateamong foresters, wildlife ecologists, academics, politicians, social scientists,and economists (Heinrichs 1984, Dawson et al. 1987, Dixon and Juelson 1987,Simberloff 1987, USDA 1988, Gup 1990).Because of this widespread interest, three major management plans have beendeveloped to protect the viability of the northern spotted owl (USDA 1988,Thomas et al. 1990, USDA 1991). These documents have been reviewed byscientists (Murphy and Noon In Press) and special interest groups alike (Boyce1987, Green 1991, Reich 1991, Sheriff 1991). Two reviews of the owl's ecologicalstatus have been conducted by the FWS (Gore et al. 1987; USDI 1990).These plans have received widespread scrutiny in the scientific literature, andthe press, by government agencies, and the courts (Simberloff 1987, Gup1990, GAO 1989, Portland Audubon Society v. Lujan 1991, respectively). Inaddition, several literature reviews and critiques have been written during thepast decade that document the history of knowledge acquisition on this uniquenocturnal predator (Solis 1980, Forsman 1984, Gutierrez 1985, Gutierrez andCarey 1985, Dawson et al. 1987, Gore et al. 1987, Forsman 1988a, Thomas etal. 1990, USDI 1990). The objective of this section is to summarize the ecologyof this controversial animal.The seminal work on the natural history of the northern spotted owl isForsman et al. (1984). However, Thomas et al. (1990) will serve as a referencepoint for specific data on certain aspects (home range size, habitat, and foodhabits) of the natural history of the northern spotted owl in this literaturereview since that work represents the most complete data yet assembled aboutthe northern spotted owl.The northern spotted owl (Strix occidentalis caunna) is a medium-sized owlfound in the Pacific Northwest. It is chocolate brown with round to ellipticalwhite spots on the body feathers and white bars on the tail. Other common* Prepared by R. J. Gutierrez1 1