Morphological Correlates of Habitat Selection in a Community of Shorebirds (Charadriiformes)

Abstract

Habitat selection by six species of shorebirds (Least Sandpiper, Semipalmated Sandpiper, Dunlin, Short-billed Dowitcher, Lesser Yellowlegs, and Semipalmated Plover) was studied on wintering and breeding ranges. Features of the terrain that characterize the feeding microhabitat were compared to the surrounding habitat and examined in relation to culmen and tarsal length. The main results were, (a) The shorebirds tend to forage along edges adjacent to taller vegetation and deeper water than are typical of the feeding habitat; (b) The diversity of the feeding microhabitat is greater in summer than in winter; (c) Culmen length is positively correlated with vegetation height and diversity of the feeding microhabitat; (d) Tarsal length is positively correlated with water depth in the feeding microhabitat; and (e) The degree to which the utilized microenvironment is distinct from the surrounding area varies among the species. The bill of a shorebird is a versatile instrument and this is not obvious from morphology alone. An increase in bill length appears to produce an increase in versatility and exploitation of a more diverse environment.