Since 1975, 101 peregrine falcon breeding sites have been documented in Arizona, New Mexico and western Texas. Eyries were found in either riverine or montane canyons, habitats which supported dense and diverse av
Since 1975, 101 peregrine falcon breeding sites have been documented in Arizona, New Mexico and western Texas. Eyries were found in either riverine or montane canyons, habitats which supported dense and diverse avian prey and provided structural characteristics that may increase prey vulnerability. Approximately 85% of the sites visited each year were occupied. Egg-laying (mid-February to mid-May) typically occurred first in the south and at lower elevations, and later in the north and at higher elevations. Mean productivity of adult pairs (mean =1.55 young/year) was comparable to rates reported for healthy populations. Poor productivity and decreased territorial occupancy in western Texas and southeastern New Mexico occurred in the presence of high levels of environmental DDE. Estimates of the breeding pop