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In the 1980's, aerial surveys in South America established that the main wintering areas of Semipalmated Sandpipers (Calidris pusilla) were found on the north coast of the continent, especially in the Guianas (Suriname, French Guiana and Guyana). Although population trend analyses have consistently shown declines in numbers of Semipalmated Sandpipers, especially for birds on migration in eastern North America, until now surveys had not been undertaken to determine whether such declines were reflected in numbers on the main wintering areas. Between December 2008 and January 2011, aerial surveys of major wintering areas in Suriname (3), French Guiana (2) and Guyana (1) were carried out. Results showed dramatic declines, with an overall total of only 21% of the 1980s total—a decrease of 79%. A variety of reasons may have contributed to the declines and include habitat changes, range shifts, sustained hunting, or increases in predation, pollution or severe weather.
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Morrison et al. (2012) studied this question.
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