Distribution and Abundance of Piping Plovers: Results and Implications of the 1991 International Census

Abstract

Assessing status and recovery of the endangered Piping Plover (Charadrius melodus) requires knowledge of the species' current distribution and abundance throughout the annual cycle. To address this issue, over 1,000 biologists and volunteers from 10 nations collaborated in the 1991 International Piping Plover Census. Approximately 2,099 sites were censused yielding the highest number of breeding (5,482 adults) and wintering (3,451 birds) Piping Plovers ever recorded. Most winter birds occurred in Texas (55%) and along other United States Gulf Coast sites (93%). Among winter birds, 51% used ocean beaches, 43% used sand or algal flats in protected bays, and 6% used areas where protected bays met ocean beaches. Breeding birds were widely distributed in small populations in the Northern Great Plains/Prairie (63.2%) and on the Atlantic Coast (36%). Few birds (N = 39) remain on the Great Lakes. Habitat use among breeding birds varied considerably across the species range. While most Atlantic (93.9%) and Great Lakes (100%) birds used sandy beaches, 59.6% of Northern Great Plains/Prairie birds used shorelines around small alkaline lakes, 18.2% used large reservoir beaches, 19.9% used river islands and adjacent sand pits, 2% used beaches on large lakes, and 0.4% used industrial pond shorelines. Change in status from previous censuses was difficult to determine. New populations were found in Montana, Colorado, and Saskatchewan, Canada; however, the distribution gap between Atlantic and Northern Great Plains/Prairie Piping Plover distribution grows as numbers decline in Minnesota; Manitoba, Canada; and the Great Lakes. Repeated international censuses every five years and a better assessment of reproductive success in local populations will help determine future population trends for the species.