Comparative Behavioral and Diversity Studies of Shorebirds in Marine and Freshwater Habitats at San Juan Island

Abstract

Shorebirds are found in marine and freshwater, and provide a variety of ecosystem functions. Our study took place on San Juan Island, Washington, USA where we observed sandpiper and plover species and how they interacted with the environment around them via diversity, substrate, and behavior scans. We used spotting scopes at a marine site at Argyle Lagoon and a freshwater site at Zylstra Lake. At these locations, morning and afternoon sessions provided temporal comparisons. We found that in correspondence with their hunting strategies and the ecological niches available, Greater Yellowlegs (Tringa melanoleuca) spent most of their time in water and Killdeer (Charadrius vociferus) were found on rocks at Argyle and vegetation at Zylstra Lake. Greater Yellowlegs fed more at Zylstra Lake but foraged equally between the two locations. We only observed Western Sandpipers (Calidris mauri) at Zylstra Lake, mainly along the shoreline in mud. The Western Sandpipers also spent the majority of their time foraging and feeding. These results indicate that prey availability and selection, and vegetation cover could play a role in substrate choice and behavior. We recommend that future studies consider seasonal changes in species diversity and environmental conditions, and how human disturbance may play a role in affecting shorebird natural life history.