Background

Photo showing three Peregrine Falcon chicks in a nest after banding.

Scientists find three Peregrine Falcon chicks in a nest during the 2007 survery and place markers on them.

Peregrine Falcons are among the many bird species that were impacted by high levels of DDT contamination in the southern California marine environment. This project was developed to monitor the natural recovery of the Peregrine Falcon on the Channel Islands. This program monitors the distribution, number of pairs, reproductive success, recruitment, and foraging behavior of Peregrine Falcons on the Channel Islands. An essential part of this program also includes contaminant analysis of eggs that didn’t hatch and measuring eggshells found in the nest. The Montrose Setttlements Restoration Program (MSRP) funded a Peregrine Falcon survey on Catalina Island in 2004 as part of the restoration planning process. In 2007, the first comprehensive Peregrine Falcon monitoring effort across the Channel Islands was completed. Later, annual Peregrine Falcon monitoring surveys on all of the Channel Islands were started in 2013 and are still ongoing.

Peregrine Falcon Project Updates

2007 Channel Islands Survey

During surveys in 2007 on all eight Channel Islands, biologists visited 35 Peregrine Falcon territories. Twenty-five territories were active with resident breeding pairs, including 7 pairs on San Miguel Island, 8 pairs on Santa Rosa Island, 7 pairs on Santa Cruz Island, 2 pairs on Anacapa Island, and 1 pair on Santa Barbara Island. Also in 2007, a total of 16 pairs successfully hatched eggs, producing 35 young. As part of the effort, eggshell thickness was analyzed for any eggshell fragments and four fail-to-hatch eggs were also analyzed for DDT contaminant levels.

Annual Channel Islands Surveys (2013-2015)

Biologists from the Institute for Wildlife Studies (IWS) completed surveys of Peregrine Falcon nesting pairs throughout the Channel Islands in 2013 and 2014. Biologists surveyed potential territories using binoculars and broadcasted Peregrine Falcon vocalizations to increase the likelihood of detection. Biologists documented nest site occupancy, timing of nesting, and reproductive success during the survey. They also band falcon chicks from nests that are accessible. During nest entries, biologists also collected any failed eggs, eggshell fragments, and prey remains for future contaminant analysis.

The Peregrine Falcon population remained steady in 2014 with 48 territories discovered, which is up slightly from the 45 territories recorded in 2013. Biologists also counted 59 chicks that hatched and more than half of them were banded.

Peregrine Falcons are definitely rebounding on the Channel Islands. The current population exceeds known historic levels and the productivity, or numbers of chicks produced per occupied territory, as well as nest success are increasing.

Project Reports