Beginning in the 2013 breeding season, IWS biologists will survey known Peregrine Falcon territories for activity on all eight Channel Islands. We will also search for new territories in conjunction with other research efforts on the islands. A primary goal of peregrine monitoring under the Montrose Settlements Restoration Program is to determine breeding chronology and outcome, including egg laying and incubation periods, reproductive success/failure, recycling attempts, and number of young produced and fledged.
Peregrine falcon nestlings at a Channel Islands nest after being banded.
Photo by Jim Campbell-Spickler
Adult peregrine falcon perched near nest site.
Photo by Jim Campbell-Spickler
American peregrine falcons (Falco peregrinus anatum) historically were common residents on all the Channel Islands (Howell 1917, Kiff 1980, Willett 1912), although the highest number of reported nests in a single year was 15 (Kiff 1980, 2000). Because peregrines and their nests are less conspicuous to casual observers than are other raptors historically found on the Channel Islands, such as bald eagles (Haliaeetus leucocephalus) and osprey (Pandion haliaetus), historical estimates of the number of peregrines on the islands were almost certainly too low (Kiff 1980) and could have been 30 or more pairs (Hunt 1994).
American peregrine falcon numbers plummeted across much of the northern hemisphere starting in the late 1940s (Hickey and Anderson 1969). North American peregrines were at their lowest numbers in the 1960s and early 1970s, at which time they were extirpated from the eastern United States and across the Midwest and reduced to a few hundred pairs in the western United States and Mexico (USFWS 2003). Approximately 100 peregrine nests in California were producing young each year until at least the mid-1940’s, with more than a third of the verified or suspected peregrine nest sites occurring within 10 miles of the ocean, including the Channel Islands (Herman et al. 1970). By 1970, the number of breeding peregrines had dropped by at least 95% in California (Herman et al. 1970, Herman 1971). It appears that nests along the southern coast suffered the earliest reductions and the peregrine population on the Channel Islands was drastically reduced or extirpated by 1955 (Herman et al. 1970), with the last reported sighting of a probable Channel Islands breeding adult occurring on Anacapa Island in 1949 (Kiff 1980). Overwhelming evidence indicated that declines in peregrine falcons and other bird species feeding higher on the food chain were a result of the eggshell-thinning effects of DDE, a metabolite of DDT (Kiff 1980, 2000, Mesta 1999; see our Bald Eagle page).
Photo by Nancee Wells
American peregrine falcons were listed as endangered in 1970 under the Endangered Species Conservation Act of 1969, and later under the Endangered Species Act of 1973 (Mesta 1999). Populations rebounded following restrictions on the use of organochlorine pesticides in Canada and the United States (banned in 1970 and 1972, respectively) and successful management activities, including the reintroduction of captive-bred and relocated peregrines (Mesta 1999). Between 1983 and 1998, the Santa Cruz Predatory Bird Research Group released 37 peregrines on the Channel Islands (Latta 2012). During a 1992 survey, Hunt (1994) located nine active nests on four of the Channel Islands. American peregrine falcons were removed from the Endangered Species list in 1999, at which time breeding targets for the Channel Islands (5 pairs) and the Pacific Coast (185 pairs) had been greatly exceeded (Mesta 1999). Another survey in 2007 located 25 active pairs on five of the eight islands, but also found that DDE contamination still appeared to be reducing the reproductive success (Latta 2012).
Herman, S.G. 1971. The peregrine falcon decline in California II. Breeding status in 1970. American Birds 25:818-820.
Herman, S., M.N. Kirven, and R.W. Risebrough. 1970. The Peregrine Falcon decline in California: I. A preliminary review. Audubon Field Notes 24:609-613.
Hickey, J.J. and D.W. Anderson. 1969. The Peregrine Falcon: life history and population literature. Pages 3–42 in J.J. Hickey (ed.). Peregrine Falcon populations: their biology and decline. University of Wisconsin Press, Madison, WI U.S.A.
Howell, A.B. 1917. Birds of the islands off the coast of southern California. Pacific Coast Avifauna 12.
Hunt 1994. Peregrine falcon studies on the Channel Islands. Expert testimony for US, et al. V Montrose, et al. 7 pp.
Kiff, L.F. 1980. Historical changes in resident populations of California Islands raptors. pp. 671673 in Power, D.M. (ed.). The California Islands: proceedings of a multidisciplinary symposium Santa Barbara, California, Santa Barbara Museum of Natural History.
Kiff, L.F. 2000. Further notes on historical Bald Eagle and Peregrine Falcon populations on the California Channel Islands. Expert report to the U.S. Department of Justice in connection with the United States vs. Montrose Chemical Corporation et al. Boise, ID. 38 pp.
Latta, B.C. 2012. 2007 Channel Islands Peregrine Falcon Study, Final Report. Prepared for the
U.S. Fish and Wildlife Service, Carlsbad, CA. Project No. 9820002.
Mesta, R. 1999. Endangered and threatened wildlife and plants; final rule to remove the American Peregrine Falcon from the federal list of endangered and threatened wildlife, and to remove the similarity of appearance provision for free-flying Peregrines in the coterminous United States. Fed. Reg. 64 (164): 46542–46558.
U.S. Fish and Wildlife Service. 2003. Monitoring Plan for the American Peregrine Falcon, A Species Recovered Under the Endangered Species Act. U.S. Fish and Wildlife Service, Divisions of Endangered Species and Migratory Birds and State Programs, Pacific Region, Portland, OR. 53 pp.
Willett, G. 1912. Birds of the Pacific slope of southern California. Pacific Coast Avifauna 7.