HANOVER, NH Researchers from Dartmouth College, Stanford University and the Smithsonians National Museum of Natural History are now one step closer to understanding the elusive migratory patterns of a songbird species called the black-throated blue warbler. The findings of this study link this species summer breeding grounds in eastern North America with its wintering sites in the Caribbean, and they help to identify where these migratory birds are most vulnerable. Black-throated blue warblers belong to a group known as Neotropical migrant songbirds, some of which have been declining in abundance in recent years.
In a paper published in the Feb. 8, 2002, issue of Science, the researchers linked the summer and winter ranges of the black-throated blue warbler by analyzing stable isotopes in feathers. The research team determined that these songbirds segregate in their Caribbean wintering grounds according to where they live and breed during the summer months in North America. The findings will be useful in developing more effective conservation initiatives for Neotropical migrants, which are a significant part of bird diversity in North America, as well as in the Neotropics, an area that encompasses Mexico, parts of South America and the Caribbean.
"Because these animals are distributed widely and travel long distances each year, it has been difficult to track and study their migratory movements with conventional techniques, such as bird banding or radiotelemetry," said Dustin Rubenstein, senior author of the paper, a 1999 Dartmouth graduate and currently a Ph.D. student at Cornell University. "We used the relatively new technique involving measurements of stable isotopes to learn where specific groups of breeding birds spend their winter. Ultimately, we hoped the results might help us understand why some populations were declining."