Abundance and Distribution of Migrant Shorebirds in Delaware Bay

Abstract

JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact support@jstor.org.. University of California Press and CooperOrnithological Society are collaborating with JSTOR to digitize, preserve and extend access to The Condor. Abstract. Northbound migrant shorebirds (Charadridae and Scolopacidae) were surveyed weekly by air on Delaware Bay beaches on the Atlantic coast of North America inMay-June 1986 through 1992. The single day peak count occurred between 26-30 May when an average of more than 216,000 birds was counted. The most abundant species were Semipalmated Sandpiper (Calidris pusilla), Ruddy Turnstone (Arenaria interpres), Red Knot (Calidris canutus) and Sanderling (Calidris alba). Our surveys documented high hemispheric counts for each of these species, and established Delaware Bay as the most important spring stopover in the eastern U.S. for these shorebirds. Counts of Sanderlings and Semipalmated Sandpipers declined significantly over the seven years; no trends for other species were detected. Differences among species in distribution along bay beaches were attributable partly to habitat factors. We suggest that a thorough understanding of shorebird abundance and habitat use in Delaware Bay is necessary to develop a conservation strategy for regulatory protection and conservation of migrant shorebirds using this area.

Avian Influenza Virus Infection Dynamics in Shorebird Hosts

“…4). Migrants typically arrive at Delaware Bay asynchronously during late April-midMay, but depart en masse over a few days in late May-early June (Clark et al, 1993;Gillings et al, 2009). Assuming that arriving birds have similar masses regardless of arrival date (Gillings et al, 2009), we compared the expected antibody prevalence among Ruddy Turnstones at the mean arrival mass (96 g; Niles et al unpublished data, cited in US Fish and Wildlife Service, 2003) to the estimated antibody prevalence on the mean departure date (1 June; unpublished data), or 48% and 99%, respectively.…”

“…The sudden aggregation of susceptible Ruddy Turnstones at Delaware Bay could provide the population threshold (Lloyd-Smith et al, 2005) needed to initiate and sustain annual AIV epidemics (Krauss et al, 2010). Up to 80% of the A. interpres morinella population migrates through Delaware Bay each year (Morrison et al, 2001), and aerial counts have exceeded 100,000 turnstones on a single day (Clark et al, 1993). During the breeding, fall migration, and wintering periods Ruddy Turnstones are typically much more dispersed, often seen individually or in small flocks (n,50;Nettleship, 2000).…”

“…An estimated .1 million shorebirds use Delaware Bay each spring (Clark et al, 1993), where, by feasting on eggs of horseshoe crabs (Limulus polyphemus) on spawning beaches, they rapidly gain up to 70% of their arrival body masses to fuel long-distance flights to breeding grounds in the Arctic (Robinson et al, 2003). Each year, shorebirds begin arriving in early May following migrations from wintering and stopover areas in South America and the Caribbean (Myers et al, 1990;Morrison and Harrington, 1992) and depart for breeding grounds during late May-early June (Robinson et al, 2003).…”

The Role of Horseshoe Crabs in the Biomedical Industry and Recent Trends Impacting Species Sustainability

“…The migration of many shorebirds, such as the red knot (Calidris canutus), semipalmated sandpiper (Calidris pusilla), ruddy turnstone (Arenaria interpres), and sanderling (Calidris alba), correspond to horseshoe crab spawning (Clark et al, 1993). The rufa subspecies of the red knot (Calidris canutus rufa), for example, is a shorebird with one of the longest migrations in the animal kingdom, traveling up to 19,000 miles from its wintering regions in the southeastern U.S., northeastern Gulf of Mexico, northern Brazil, or the southern tip of South America to its breeding ground in the Canadian Arctic (U.S. Fish and Wildlife Service, 2015).…”

The Horseshoe Crab, Limulus polyphemus: 200 Million Years of Existence, 100 Years of Study

“…According to Botton et al (1994), staging areas serve as intermediate stopover points for the birds to feed before continuing their migration. An estimated 425,000 to 1,000,000 birds stop in Delaware Bay staging areas during May and June (Myers, 1981(Myers, , 1986Myers et al, 1987;Shuster, 1982a;Clark et al, 1993), as they travel from their South American wintering grounds to their Arctic breeding grounds (Myers, 1986). The timing of their migration north is critical, as the birds need to reach the Arctic while the snow is melting to ensure their eggs will hatch in time for the annual insect hatch, which comprises the primary diet of the young shorebirds (Clark, 1996).…”