Although flight feathers should, in theory, reflect isotopic ratios of the non-breeding habitat, the isotopic ratios of individual feathers may vary due to several factors, including large-scale movements of shorebirds during the period when feathers are being grown. If large movements and isotopic variations occur, the use of isotopes to identify the non-breeding “site” would be more difficult to accomplish. Recent isotope analyses of Pectoral Sandpiper wings by the USGS laboratory in Denver, however, show that carbon and nitrogen isotope ratios vary little among individual flight feathers (see figures below). These data provide support for the notion that Pectoral Sandpipers may be very local in their movements, at least during the molt period of December and January. They also serve as encouragement for continuing to investigate isotopic analysis as a means of identifying non-breeding grounds of neotropical migrants.
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Ratios of 13C in flight feathers of a Pectoral Sandpiper wing. |
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Ratios of 15N in the flight feathers of a Pectoral Sandpiper wing. |
U.S. Department of the Interior | U.S. Geological Survey
URL: http://www.fort.usgs.gov/resources/spotlight/shorebird_isotopes/isotopes_wings.asp
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