Predatory bird populations in the east Mojave Desert, California

We surveyed 7 species of predatory birds weekly during a 12-month period (D ecember 1992 through November 1993) in the east Mojave Desert, California. The Common Raven (Corvus corax) was the most frequently observed species wi th an average of 6.9 sightings per 100 km. Turkey Vultures (Cathartes aura) , Red-tailed Hawks (Buteo jamaicensis), Loggerhead Shrikes (Lanius ludovici anus), American Kestrels (Falco sparverius), Golden Eagles (Aquila chrysaet os), and Prairie Falcons (Falco mexicanus) were seen in decreasing order of frequency of observation through the study period. Ravens, Red-tailed Hawk s, Loggerhead Shrikes, American Kestrels, and Prairie Falcons were seen thr oughout the year. Turkey Vultures were not present during winter months, wh ile Golden Eagles were seen only during November and December. Turkey Vultu res, Red-tailed Hawks, and ravens were most numerous on agricultural lands, while Loggerhead Shrikes were most common at urban areas. Raven numbers in creased with increasing number of linear rights-of-way parallel to the surv ey route. Perching was the most common behavior type, although Turkey Vultu res and ravens were often observed sealing, flying, or standing on the grou nd near highways. Transmission powerline towers and telephone poles were us ed as perch sites disproportionately to availability.