Peregrine Falcon Survival and Resighting Frequencies on the Washington Coast, 1995-2003

Abstract

We estimated survival for Peregrine Falcons (Falco peregrinus) in beach-dune habitat along the Washington coast. We captured and color-banded 76 Peregrine Falcons during 438 surveys by vehicle on three coastal beaches in Washington from January 1995 to May 2003. We captured 45 females and 31 males; 68% (52) were <1 yr old and 32% (24) were ≥1 yr old. Based primarily on photographs (N = 72) showing plumage coloration, 76% (N = 55) of the individuals captured were F. p. pealei, 7% (N = 5) were F. p. anatum, 3% (N = 2) were F. p. tundrius, and 14% (N = 10) showed intermediate characteristics and could not be identified to subspecies. Thirty-nine (51%) of the color-banded individuals were observed alive at least once after banding. Using program MARK, we estimated that the apparent survival rate (Φ) for all age and sex classes over a 3-mo interval was 87.9 ± 2.0% (±SE) and the annual survival rate was 59.7 ± 5.4%. We found relatively high use of the study areas by peregrines in fall, winter, and spring, and low use in summer. Resighting probabilities (P) were lower in summer compared with other seasons. During fall, winter, and spring, the 3-mo resighting probability (P) was 45.4 ± 7.9% for juveniles, 35.9 ± 5.0% for adult females, and 16.7 ± 4.5% for adult males.