Introduction

Author: Erica Nol (EN), Dept. Biology, Trent University, Peterborough, Ontario, Canada.

The American Oystercatcher is a large, conspicuous shorebird, common in coastal salt marshes and sand beaches throughout the central part of its range. One of the few birds to specialize on bivalve mollusks living in saltwater, this species is completely restricted to marine habitats. Two races breed in North America—the eastern nominate race along the Atlantic coast from Massachusetts south, and a second race along the Pacific coast from northwestern Baja California south. While the eastern race has been studied extensively across its range both during winter and the breeding season, the biology of the western race is poorly known and this population may also be at risk both from coastal development and hybridization with the American Black Oystercatcher (H. bachmani). Eastern oystercatchers regularly winter in large flocks, from Virginia south along the Atlantic and Gulf coasts.

Although this oystercatcher inhabits coastal areas where human encroachment, habitat loss, and destruction are threats, large coastal reserves or refuges in the Mid-Atlantic States help to protect the center of its abundance, especially in winter. This species can breed on dredge spoil islands, and is often the most common breeder in such locations. Its future success, however, depends on its coexistence with humans in salt marshes and dunes areas, and possibly on the mitigation of factors affecting any rise in sea level.

The recognition, in 2000, that the entire North American population of this species numbered around 10,000 individuals (Brown et al. 2001), led to a flurry of research on its biology, including a concerted effort to document total numbers using a mixture of air, boat and land surveys (Brown et al. 2005). This work led to the realization that Virginia North Carolina and South Carolina were extremely important as both breeding and wintering areas (Sanders et al. 2004, 2008, Wilke et al. 2005, 2007, McGowan et al. 2005a and see tables 4 and 5 in the Demography and Populations section of this account)) and studies on disturbance (Sabine et al. 2008), and demography (using resightings of marked birds) across the range were initiated (McGowan et al. 2005a, Simons and Schulte 2010). Since the publication of the original BNA on American Oystercatcher (1994), nearly 30 papers have been published on the biology of this specialized forager and coastal inhabitant. This activity has resulted primarily from coordinated efforts of a team of interested managers and biologists who comprise the American Oystercatcher Working Group.