Kristin Gadd, 334/844-5741


AUBURN -- Through applying a combination of the sexual selection theory and biogeography, two Auburn University researchers are trying to determine why some species of birds are common in one location, but rare in others.

Assistant Professor Douglas Robinson and Associate Professor Geoffrey Hill of the Department of Zoology and Wildlife Sciences are studying plumage to explore possible reasons for sporadic distribution among different species.

The knowledge that female birds choose to mate with males that display bright plumage suggests that feathers may be an indicator of not only individual health, but population health as well, according to Hill.

"The brilliance of a male's plumage is dependent on how healthy he is when he grows his feathers," Hill said.

To reach his peak, the male must live in a good environment, he added.

The researchers are examining geographic range -- the area containing all sites in which a species is known to occur -- and distribution. The abundance of a species is greatest near the center of the range and declines towards the edge of the distribution, Robinson says. Optimal environmental conditions are found in the middle of ranges and decrease towards the edge of the range, leaving males there with dull plumage.

Robinson and Hill believe that the less-brilliant plumage indicates reduced condition of birds in the outer parts of the range, eventually reaching a point where individuals no longer can survive.

The researchers will test their prediction first by measuring plumage traits of several bird species in three large museum collections at Louisiana State University, the Field Museum of Natural History in Chicago and the National Museum of Natural History in Washington, D.C. They then will focus on one species, the Painted Bunting, and take measurements on live birds in the field.

The two faculty members have been awarded a $3,000 grant through AU's Faculty Mentoring Program to pursue their research.

"We will use the award to travel and gather preliminary data needed for constructing a convincing grant application to the National Science Foundation," Robinson said.

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