Habitat complexity and patch choice: spatiotemporal distribution of foraging shorebirds on intertidal sand flats

This early-winter study correlated patch- and landscape-level factors with spatial and temporal shorebird foraging patterns on four discrete, yet connected, intertidal sand flats in the New River Inlet, North Carolina, USA. Shorebirds were distributed non-randomly among flats, with major differences in abundance and species composition strongly correlated with the benthic macroinvertebrate community. Sediment characteristics added explanatory power; benthic macroinvertebrate community and sediment composition together explained two thirds of the variation in shorebird community patterns. Influence of landscape characteristics such as area-to-edge ratio of the flat and nature of the surrounding habitat (indicative of varying predation risk) likely contributed to the unexplained variation. Sedimentary influence was exemplified when probing shorebirds avoided a sand flat that contained large amounts of coarse material (gravel, shell). Significantly higher prey (polychaete) densities on this flat suggested that the coarse material acted as a refuge for infaunal prey by deterring probing shorebirds