This
study, The Use of StableIsotopes to Link Seasonal Habitats and Identify
Sub-populations of Migratory Shorebirds, will analyze flight feathers
taken from birds during four phases of their annual cycle—winter,
spring migration, breeding, and fall migration—and will focus on
three species: the Pectoral Sandpiper (Calidris melanotos), Baird’s
Sandpiper (Calidris bairdii), and White-rumped Sandpiper (Calidris
fuscicollis). Specific objectives are to:
1. Verify and calibrate the isotopic and trace element signatures of feathers collected across the winter range. Flight feathers will be collected on the winter (non-breeding) habitat after molt and just before spring migration across a range of latitudes between Brazil and southern Argentina. Small samples of precipitation, plants, and invertebrates will also be collected at each site. The feathers, precipitation, plants, and invertebrates will be analyzed for a suite of isotopes including hydrogen, carbon, nitrogen, and sulfur as well as the trace elements 207Pb/206Pb and 87Sr/86Sr. The data will be used to construct predictive relationships between the isotopic compositions of feathers and latitude.
2. Assess the degree of population subdivision on the breeding grounds. Flight feathers will be collected from nesting females across their Arctic breeding grounds between 90ºE and 90ºW longitude. The null hypothesis that a bird’s breeding location cannot be predicted from knowledge of its non-breeding latitude (i.e., birds are mixed on the breeding grounds) will be tested.
3. Assess the degree of mixing on specific migration stopovers. Feather samples will be collected, both early and late during spring and fall migration, across an east-west gradient in the migration corridor (roughly between the Atlantic coast and eastern Colorado). The null hypotheses to be tested are: (a) a bird’s migration path is not related to its non-breeding latitude, and (b) a bird’s timing of migration is not related to its non-breeding latitude.
U.S. Department of the Interior | U.S. Geological Survey
URL: http://www.fort.usgs.gov/resources/spotlight/shorebird_isotopes/isotopes_studyobj.asp
Page Contact Information: AskFORT@usgs.gov
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