Coal Oil Point Reserve

During the May 2015 Refugio Beach oil spill, federally threatened western snowy plovers (Charadrius nivosus nivosus) were feeding with their recently hatched chicks on southern California beaches. They primarily forage on invertebrates in the wrack and wave-washed swash zone and were directly threatened by both the oil and the actions of the clean-up crews. During the spill, the extent and location of oiling observed on western snowy plovers at Coal Oil Point Reserve, in Santa Barbara, were documented. In addition, annual monitoring of reproductive success was conducted (i.e., number of nests, number of eggs laid, number of chicks fledged, etc.), contributing to data collected on this population since 2001. Although no direct mortality of western snowy plovers was observed during the spill, a spike in the percentage of infertile eggs was observed in the year following the spill. As part of the Natural Resource Damage Assessment, estimated oil ingestion rates were compared to exposures associated with reproductive harm in other avian oil toxicity studies. A plausible connection between oil ingestion via preening and feeding and the increase in egg infertility in western snowy plovers at Coal Oil Point Reserve was demonstrated.