Overview of Shorebird Abundance and Distribution in Wetlands of the Pacific Coast of the Contiguous United States

We corrdinated censuses from April 1988 to April 1995 to obtain an overview of shorebird abundance and distribution in Pacific Coast wetlands of the contiguous United States. We attempted to acquire at least 3 years of data for all major wetlands from counts within a short time window each fall, winter, and spring. Fourteen abundant, 8 moderatcly abundant, and 21 rare-to-uncommon species were recorded. For temperate-zone breeders. peak periods of abundance were fall or winter and, when discernible for arctic breeders, mostly fall or spring. Arctic breeders were relatively more abundant than temperate-zone breeders in Oregon and Washington wetlands. All five of the most abundant temperate breeders were limited primarily to California wetlands in all seasons. Only for Western Sandpiper (Calidris mauri) and Dunlin (C. alpina) did the estimated total individuals present simultaneously in all wetlands exceed 100.000. Fifty-six of 66 sites surveyed had at least four counts and at least 100 shorebirds on one or more counts; 38 of the 56 sites held at least 1% of 1 of 13 key species during at least one season. San Francisco Bay accounted for 24-96% of the estimated totals for key species; Grays Harbor, Willapa Bay, Humboldt Bay, Tomales Bay, Point Reyes Esteros, Bolinas Lagoon, Elkhorn Slough, Morro Bay, Mugu Lagoon, Bolsa Chica, Mission Bay, and San Diego Bay held at least 1% of at least half the key species in at least one season. The usefulness of five criteria for selecting key wetlands for shorebird conservation are examined and potential threats are discussed.

[1]  S. Haig,et al.  Monitoring species richness and abundance of shorebirds in the western Great Basin , 1998 .

[2]  Cohen,et al.  Accelerating invasion rate in a highly invaded estuary , 1998, Science.

[3]  J. Burger.  EFFECTS OF MOTORBOATS AND PERSONAL WATERCRAFT ON FLIGHT BEHAVIOR OVER A COLONY OF COMMON TERNS , 1998 .

[4]  Donald R. Strong,et al.  Status, prediction and prevention of introduced cordgrass Spartina spp. invasions in Pacific estuaries, USA , 1996 .

[5]  John T. Cayford,et al.  Population estimates for waders Charadrii wintering in Great Britain, 1987/88–1991/92 , 1996 .

[6]  R. Nicholls,et al.  Adapting to sea‐level rise: Relative sea‐level trends to 2100 for the United States , 1996 .

[7]  J. Turpie,et al.  Prioritizing South African estuaries for conservation: A practical example using waterbirds , 1995 .

[8]  G. Page,et al.  Shorebirds in western North America: Late 1800s to late 1900s , 1994 .

[9]  S. Skagen,et al.  Toward Conservation of Midcontinental Shorebird Migrations , 1993 .

[10]  John C. Callaway,et al.  The introduction and spread of smooth cordgrass (Spartina alterniflora) in South San Francisco Bay , 1992 .

[11]  S. Senner,et al.  Approaches to the Conservation of Coastal Wetlands in the Western Hemisphere , 1991 .

[12]  T. Dahl,et al.  Wetlands Losses in the United States 1780's to 1980's , 1990 .

[13]  J. Goss-Custard,et al.  RATES OF CHANGE IN THE NUMBERS OF DUNLIN, CALIDRIS ALPINA, WINTERING IN BRITISH ESTUARIES IN RELATION TO THE SPREAD OF SPARTINA ANGLICA , 1988 .

[14]  J. Buchanan.  THE ABUNDANCE AND MIGRATION OF SHOREBIRDS AT TWO PUGET SOUND ESTUARIES , 1988 .

[15]  S. Herman,et al.  INTERHABITAT MOVEMENTS OF WINTERING DUNLINS IN WESTERN WASHINGTON , 1985 .

[16]  R. Morrison.  Migration systems of some New World shorebirds , 1984 .

[17]  S. Senner,et al.  Conservation of Nearctic Shorebirds , 1984 .

[18]  R. W. Storer.  The Seasonal Occurrence of Shorebirds on Bay Farm Island, Alameda County, California , 1951 .