THE BIRD GROUP ™

Peregrine eggs. Photo: Brian Latta

Janet Linthicum has been collaborating with biologists and toxicologists from the University of California, Berkeley, California Environmental Protection Agency, Carnegie Institution for Science, and the University of California, Santa Cruz on investigations of contamination of Peregrine Falcons and their prey with brominated flame retardants (PBDEs) and PCBs.  By providing Peregrine egg contents for analysis and data on nesting Peregrines and their prey collected since the 1970s Janet has been contributing to the knowledge of the pathways and extent of flame retardant contamination in the environment. 

These studies have detected unusually high levels of flame retardants in California Peregrine Falcon Eggs, especially those from urban nest sites.  Animal studies have shown PBDEs to be neurodevelopmental toxins, disruptors of thyroid function, and liver toxins.

Survey Manager Gregg Doney on the Padre Island flats with a juvenile peregrine. photo: Brian Latta

In collaboration with Earthspan, Centers for Disease Control, the Falcon Research Group, and other researchers, TBG field biologists have been participating annually in the Padre Island Peregrine Falcon Survey, gathering data for various studies on Peregrine Falcons during their fall migration for over 20 years.  These Peregrines originate and breed across the Northern Hemisphere from Alaska to Greenland and winter as far south as Tierra del Fuego, Argentina.  Padre Island on the Texas Gulf Coast is a major stopover point for Peregrines during their fall southward migration and the only known stopover location for falcons migrating northward in spring.  Biologists survey the island for Peregrines, trap and band them, take morphometric measurements, collect blood and feather samples for DNA and stable-isotope analysis to determine their natal origin, and collect samples to monitor the spread of West Nile Virus and Avian Influenza.  The birds are released unharmed to continue their migraton. TBG biologists participate in the survey on a volunteer basis each fall.

Radio-tagged Prairie Falcon in Central California

Brian Latta is collaborating with East Bay Regional Parks District Wildlife Biologist Dr. Doug Bell on a multi-year radio-telemetry study of the movements of Prairie Falcons nesting in the East Bay Hills of Contra Costa and Alameda Counties.  The study area ranges from Mt. Diablo south to the ranch lands around Calaveras Reservoir.  This study is concerned with the movements, range, habitat use, and nest site fidelity of adult Prairie Falcons and has implications for future management and land-use decisions.

Photo: Brian Latta

Brian Latta is working with Paul Collins of the Santa Barbara Museum of Natural History and Gary Roemer of New Mexico State University on an investigation of Golden Eagle predation on the Channel Islands using stable-isotope analysis.  By analyzing prey remains from Golden Eagle nests and feather samples collected from Golden Eagles we captured on the islands, we hope to shed more light on the factors leading to and supporting the invasion of Golden Eagles to the California Channel Islands that resulted in the near extinction of the Island Fox on three of the northern islands.

Golden Eagle chicks in the nest. Photo: Brian Latta

We are awaiting microsatellite and mitochondrial DNA analyses of Golden Eagle blood and eggshell membrane samples we collected from the CA Channel Islands which is being performed by Sandy Talbot at the USGS Alaska Science Center with funding provided by Channel Islands National Park.  We hope to determine the relatedness of all the Golden Eagles we removed from the Channel Islands, determine which eagles originated from island nests, and test the hypothesis that the island population (42+ individuals) originated from a few founders that dispersed there from the mainland in the late 1980s.

Young peregrine prior to release. Photo: Brian Latta

We are continuing to collaborate with University of Illinois, Chicago Ph.D. candidate, Isabel Caballero, John Bates, Associate Curator at the Field Museum of Natural History, and Doug Bell of East Bay Regional Parks on a study using newly developed microsatellite markers to explore a number of questions about the current genetic structure of the North American peregrine population.  Brian Latta and Joel Pagel (USFWS) have been collecting blood samples from California and Oregon peregrines for DNA analysis for over a decade and a half and have submitted these samples and the corresponding data to Isabel for this study.  Among the questions being asked are how have reintroductions effected peregrine genetic diversity and how does this differ between eastern, western, and Canadian populations.

Brian Latta and TBG associate Nick Todd work with Paul Collins of the Santa Barbara Museum of Natural History to excavate historic Bald Eagle nests on the Channel Islands that have been vacant since the species was extirpated from the islands by DDT contamination by the 1950s.  We have been collecting and identifying prey remains from these nests attempting to determine the eagles’ pre-DDT era diet and to detect shifts in their diet in response to changes in the prey populations and the introduction of non-native prey species.  We are also collecting eggshell fragments for measurement in search of direct evidence of the effect of DDT/DDE contamination.