Amanda T Martinez; CSULB;; Christine R. Whitcraft

The California least tern (CLT: Sternula antillarum browni) is an endangered seabird. Its phenology brings the CLT to the coast of California and Mexico each year to nest in colonies. An important factor believed to contribute to nesting success is prey availability; this study focuses on CLT foraging habits and prey availability at three colonies in southern California (2018-2020): Huntington Beach, Seal Beach, and Burris Basin. Foraging surveys were used to identify habitat use near each colony. Fish surveys were used to describe fish communities in areas where foraging had been observed. Community metrics from fish surveys were compared to guano and dropped fish to understand how food availability relates to CLT diet. CLT had higher use of open water habitats in close proximity to breeding grounds. Overall fish communities varied among habitat types and the combination of diet metrics suggested that CLT had access to high abundances of slender-bodied fish they were able to catch and consume. Suggesting prey availability did not limit the nesting success of the CLT, other factors may be influencing their population decline. Information from this study can help guide management of CLT colonies, provided a greater understanding of prey availability and diet of CLTs.

Birds III   Student Paper InPerson Presentation