Dispersal and population dynamics of the New England American oystercatcher (Haematopus palliatus)

Report submitted in fulfillment of a 2006 Nantucket Biodiversity Initiative grant Dispersal is a crucial ecological process that drives such processes as range expansion and colonization. Since the early 1900’s the breeding range of the American Oystercatcher, Haematopus palliatus, has expanded north along the Atlantic Coast. Since the 1970’s the species has assumed a prominent role as a nesting shorebird along the Atlantic Coast including Cape Cod, Massachusetts and the surrounding islands. We examined the productivity and movement of a population of oystercatchers from 2005-2007 in Nantucket County, Massachusetts. From 2005 to 2007, a total of 144 oystercatchers (100 adults, 44 juveniles) were individually marked using a coded color band. Movement during the breeding season and persistence of oystercatchers at nesting grounds were recorded for marked individuals. Auxiliary markings continue to provide new information about nest site fidelity and have the potential to provide information about the population dynamics of the oystercatcher in Massachusetts. Of the 67 adults marked in 2005-2006, 43 (64.2%) have been resighted during the non-breeding season in an array of sites throughout the accepted winter distribution. In 2006, 20 of 26 marked adults returned to their respected beaches in Nantucket County, which supports a characteristic often assumed for the American Oystercatcher, breeding site fidelity. This measure of fidelity (or return rate) can be used as an early, baseline estimate of adult survival. Based on this mark-resight model for estimating return rate, adult survival is ≥0.77 (0.084 SE)