ABUNDANCE AND DISTRIBUTION OF MIGRANT SHOREBIRDS IN DELAWARE BAY

Northbound migrant shorebirds (Charadridae and Scolopacidae) were surv eyed weekly by air on Delaware Bay beaches on the Atlantic coast of No rth America in May-June 1986 through 1992. The single day peak count o ccurred between 26-30 May when an average of more than 216,000 birds w as counted. The most abundant species were Semipalmated Sandpiper (Cal idris pusilla), Ruddy Turnstone (Arenaria interpres), Red Knot (Calidr is canutus) and Sanderling (Calidris alba). Our surveys documented hig h hemispheric counts for each of these species, and established Delawa re Bay as the most important spring stopover in the eastern U.S. for t hese shorebirds. Counts of Sanderlings and Semipalmated Sandpipers dec lined significantly over the seven years; no trends for other species were detected. Differences among species in distribution along bay bea ches were attributable partly to habitat factors. We suggest that a th orough understanding of shorebird abundance and habitat use in Delawar e Bay is necessary to develop a conservation strategy for regulatory p rotection and conservation of migrant shorebirds using this area.