Methods and materials, for locating and studying spotted owls.

FORSMAN, ERIC D. Methods and materials for locating and studying spotted owls. Gen. Tech. Rep. PNW-162. Portland, OR: US. Department of Agriculture, Forest Service, Pacific Northwest Forest and Range Experiment Station; 1983. 8 p. Nocturnal calling surveys are the most effective and most frequently used technique for locating spotted owls. Roosts and general nest locations may be located during the day by calling in suspected roost or nest areas. Specific nest trees are located by: (1) baiting with a live mouse to induce owls to visit the nest, (2) calling in suspected nest areas to stimulate the female to call or fly from the nest, or (3) observing adults during prenesting diisplays. An effective technique for climbing large nest trees is to rig the.tree with a climbing rope. Mechanical climbing aids are then used to ascend the rope. The principal method used to determine the diet is identification and enumeration of prey in regurgitated pellets. The most effective method of trapping spotted owls.is with a noose pole. Other trapping methods include mist nets, bal-chatri traps, bow nets, and dip nets. Radio transmitters for long-term radiotelemetry studies are usuall’y attached with a backpack harness; the antenna should be reinforced to keep it fr0.m crimping or breaking. Keyword,s: Wildlife surveys, birds, owls (spotted). In recent years, a variety of methods for locating and studying spotted owls (Strix occidentalis) have been developed. Many of these techniques have spread by word-of-mouth among biologists but have not been well described in the literature. This manual describes the techniques that I (and other biologists) have found most effective for locating and studying spotted owls. I have written the manual with the inexperienced observer in mind, but it should be useful to experienced owl biologists as well.