Body condition in three Calidris species during northward and southward migration in La Laguna de Tacarigua, Venezuela

Migratory shorebirds of the genus Calidris use Venezuelan wetlands during their migrations to non-breeding areas in South America and breeding areas in North America. Between July 2008 and April 2009, we examined body mass, level of subcutaneous fat, and flight range of 122 individuals of three species of shorebirds, Least Sandpiper Calidris minutilla, Semipalmated Sandpiper C. pusilla and Western Sandpiper C. mauri, at Laguna de Tacarigua, Venezuela. Least and Semipalmated Sandpipers had significantly higher body masses and fat scores on northward than southward migration. During southward migration, mean body mass was 18.4, 18.5 and 20.6 g, in Least, Semipalmated and Western Sandpipers, while during northward migration, mean body mass was 22.3, 22.0 and 21.4 g, respectively. Of the 122 color-banded birds, 24 were resighted in the study area, and seen for 2.1 ± 1.0 days during southward migration and 11.3 ± 12.5 days during northward migration. Least and Western Sandpipers had mean positive estimated flight ranges during both migratory periods ranging from ca. 100 km to 3,800 km. In Semipalmated Sandpipers, no individuals had the theoretical minimum weight required to migrate to areas more than 100 km from the study area. La Laguna de Tacarigua could be the first stopover site for some Least and Semipalmated Sandpipers after crossing the Caribbean Sea, while it is likely an accidental stopover site for Western Sandpipers. We proposed that during our study La Laguna de Tacarigua provided the resources these migrants need to improve their body condition and move to other nearby areas and hence it is an important site for continued monitoring and protection.