PHONE: (313) 593-5518
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.
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
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
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
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 http://www.umd.umich.edu/dept/rouge_river/.