Sediment ingestion of two sympatric shorebird species

Black-bellied plovers (Pluvialis squatarola) have short bills and primarily peck while foraging whereas Willets (Catoptrophorus semipalmatus) have lon g bills and primarily probe with bills open in sediments. Intestinal digest a were collected from these species at sympatric overwintering sites in sou thern California near San Diego to relate sediment ingestion to bill length and feeding behavior. Plover digesta contained an estimated 29% sediment, and Willet digesta an estimated 3% sediment. Techniques based on acid insol uble ash and on the elemental markers of Al, Fe, and Ti in digesta provided similar results. High Ca concentrations in Willet digesta along with our o bservations suggested that the Willets in our sample fed primarily on mollu scs and crustaceans. Sediment ingestion may be species-specific, not necess arily linked to bill length or probing behaviors, and may greatly affect a bird's exposure to environmental contaminants in sediment. (C) 1998 Publish ed by Elsevier Science B.V. All rights reserved.