Migratory songbird breeding linked to wint...( e same habitat-specific signature. Sim...)

By testing for isotopes in American redstarts as they arrived at Hubbard Brook in the spring and settled into breeding areas, the investigators were able to determine that early arrivers were, indeed, those birds that had spent the winter in wet, tropical environments. Late arrivers carried the isotope signature of drier, scrub environments. Thus, even though the investigators did not know the actual wintering location of the individual redstarts arriving at Hubbard Brook, they could determine which type of habitat they had occupied during the preceding winter.

"These findings suggest that migratory birds in winter are competing for good quality habitats that are in short supply," says Holmes. "The consequences may show up at other stages of their annual cycle. Conservation efforts need to take into account this interplay of factors that affect these species throughout the year, including not only the quantity but also the quality of the habitats they occupy."

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Contact: Nancy Serrell
nancy.serrell@dartmouth.edu
603-646-2117
Dartmouth College
3-Dec-1998