| It is estimated that there were 15-30 pairs of breeding American peregrine falcons (Falco peregrinus anatum) on the California Channel Islands in the early- to mid-1900s, but they were extirpated by the early 1960s, likely as a result of DDE (a metabolite of DDT) contamination of the Southern California Bight. Small-scale reintroductions occurred on several islands between 1983 and 1998, but there were few comprehensive surveys conducted after the mid-1990s. We conducted annual surveys for peregrines on all 8 California Channel Islands in 2013-2015 to determine population size, nesting success and productivity. We located 45-48 occupied territories each year and the estimated population size now exceeds that of the pre-DDT era. Nesting success averaged 68%, with mean productivity of 1.5 chicks per occupied territory. Although the levels of productivity appear sufficient to maintain the population, factors such as juvenile/adult survival and emigration/immigration rates play an important role in population persistence. Continued population monitoring and banding of young could provide an improved understanding of these population parameters for the Channel Island peregrines and help determine whether contaminants or other issues are negatively impacting the population. |