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DATE: Oct. 12, 2005

25,000th bird banded at UM-Dearborn's Rouge River Bird Observatory

DEARBORN---A juvenile white-throated sparrow banded yesterday (Oct. 11) was the 25,000th new bird banded by the Rouge River Bird Observatory (RRBO) at the University of Michigan-Dearborn since the observatory was established in 1992.

This white-throated sparrow was the 25,000th new bird banded at the Rouge River Bird Observatory.

White-throated sparrows (Zonotrichia albicollis) breed across Canada, northern New England, and into northern Minnesota, Wisconsin, and Michigan, according to Julie Craves, an ornithologist at the RRBO.

"They spend the winter south of their nesting range, mostly in the southeastern U.S." Craves said. "While a few will winter in southeast Michigan, most are just passing through. It is one of the most common migrants in this area, and we have banded nearly 1,600 of them since 1992."

The RRBO has banded an average of more than 80 white-throated sparrows each fall over the last 14 years. "More than 10 percent of them are recaptured a day or more after banding during their fall migration here, making them one of the 45 species that are part of a long-term study on the importance of urban natural areas to migrant birds," Craves said.

Each day during the migration season, birds need to find a safe place to rest and refuel, she said. "Data collected on banded white-throated sparrows that stop on the UM-Dearborn campus in fall show that they stay an average of 4.6 days and gain an average of about 2 percent of their body weight, indicating that they are finding suitable resources in the area."

Similar data has been gathered for other species banded at the RRBO, showing even more dramatic results. "For example, compared with the white-throated sparrow the gray-cheeked thrush (Catharus minimus) breeds even further north, in boreal Canada, and winters much farther south, in South America," Craves said.

Nearly 20 percent of the gray-cheeked thrushes banded on the UM-Dearborn campus are shortly recaptured. During their average five-day stay, they gain nearly 10 percent of their body weight.

"No other bird observatory in North America has this type of data for migrant birds in urban areas," Craves said. "This type of life history data, along with determining which resources are important to different species, is critical in making informed conservation decisions which will help to preserve habitats for migratory birds throughout North America."

The Rouge River Bird Observatory, located in UM-Dearborn's Environmental Interpretive Center, is dedicated to research on the importance of stopover sites for migratory birds.

Craves and colleagues study why birds stop at one site and not others, how long they stay in one area and what habitat features help the birds migrate successfully. "These questions are critical conservation issues. Many bird populations, particularly those of birds that migrate to the tropics, have been declining at an alarming pace," Craves said. "Our research indicates UM-Dearborn is a very important area for migratory birds."

The Rouge River Bird Observatory is supported by donations from corporations, foundations and individuals. For more information see





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