Shorebird Behavior at Two Sites on San Juan Island, Summer 2021

Abstract

Shorebird species have habitat preferences and feeding adaptations that help them reduce competition. The San Juan Islands support many of these shorebird species with its resources. We aimed to study and compare various aspects of shorebird behavior at Jackson Beach and False Bay, two locations on San Juan Island. We recorded abundance and species composition, as well as substrate use and behavior through focal animal sampling. We also compared high and low tide differences at Jackson Beach. Killdeer (Charadrius vociferus), western sandpipers (Calidris mauri), and greater yellowlegs (Tringa melanoleuca) were the most abundant species. Low tides at Jackson Beach had a higher abundance in greater yellowlegs and killdeer, while western sandpipers showed no major preference. Greater yellowlegs were found most often wading, whereas western sandpipers preferred algae, and killdeer used all substrates roughly the same amount. Lastly, the sandpipers at Jackson Beach and False bay spent most of their time foraging, while the killdeer spent most of their time standing at both sites. These findings suggest that killdeer use False Bay and Jackson Beach as a resting site, whereas the sandpipers are there to forage.