Through conservation breeding and adaptive management, endangered California condors have returned from the brink of extinction to a current population of over 400 at sites in California, Arizona and Baja California. Yet California condors feeding in coastal habitats are showing signs of reproductive problems such as eggshell thinning, which can be caused by exposure to certain pollutants known as endocrine-disrupting compounds. This project provided a detailed assessment of dietary contaminant exposure for condors living in coastal habitats.
The project screened for environmental organic contaminants by a novel non-targeted analytical technique and then determined their endocrine-disrupting potential via in vitro hormone receptor assays. The project also established that consumption of marine mammals is the likely primary source of these halogenated organic compounds (HOCs). This project assessed the chemical profiles of Baja California condors and compared those profiles with California-based coastal and inland condors by measuring endocrine-disrupting chemicals in marine mammal carcasses collected from the coast of the upper Gulf of California and found California condors living in reintroduction sites in Baja California have 300-2000 times less DDT burdens than condors living in the state of California.
These results can help inform wildlife managers who make species management decisions, including habitat selection, for condor reintroduction efforts by highlighting the value of the Baja California reintroduction site. The project also strengthened biomonitoring techniques and informed decision-makers about contaminants of concern in the coastal region.