Allison Korte and Gary Worthington peer through binoculars and listen intently from a bank of the Boise River.

Korte makes some marks on a clipboard, notes that 10 minutes are up, and the two mount their bikes, peddle to the next stop and repeat the process.

This is what Korte's summer will look like - at least for the next few weeks.

Along with three volunteers, the Boise State biology graduate student will perform bird counts over a six-week period at 50 spots along the river between Lucky Peak Reservoir and Star, noting all birds seen or heard within about 50 yards of each stop.

Next summer, Korte will repeat the bird-count exercise and then analyze the data for her master's thesis on the impact of urbanization on Ada County's bird populations.

"I came up with the idea of conducting this study during one of my daily walks along the Greenbelt," said Korte, a Boise native. "Through the years I have seen Boise grow and grow and have noticed a big increase in Greenbelt use ... The community has strived to keep the riparian habitat fairly well intact along the river, which creates a great study site for the effects of urbanization and human disturbance on riparian wildlife."

The Boise River runs through natural, agricultural, residential and commercials areas. Just like people, some birds prefer city life while others prefer the living in the country. As agricultural and natural areas are developed, the kinds of bird species living in an area can change. Some species, like crows, robins and starlings, are well adapted to city life and human disturbances, while other species like flycatchers and orioles do not like being in cities and close to people, Korte said.

"Urbanization can lead to the simplifying of habitats, eliminating many important resources needed for certain species, therefore, yielding an ecosystem with a few dominant species rather than many species," Korte said.

She and her volunteers will note both birds and vegetation and surrounding landscape at each site, to see if the species change as the landscape does.

"The number of species seen may also be larger in the outskirts of town since it is a more complex habitat that can support larger numbers and a wider range of species," Korte said.

Urbanization can have many effects on wildlife and the environment, some positive, some negative, Korte said. "It can lead to fragmentation or elimination of natural habitat, making it more difficult for native animals to travel, nest, forage and feed," she said.

But in arid Southwest Idaho, urbanization means more trees, flowers and grass, which provide food for some bird species. Insect-feasting birds, though, often cannot find enough to eat in the concrete and asphalt jungle, which also can be hazardous for ground-nesting birds.

"City living is not easy on birds," said R.L. Rowland, who has participated in more than 20 annual Boise bird counts with the Golden Eagle Audubon Society and is helping Korte with her bird counts. "A city is a relative biological desert except for people who grow trees, put in feeders or native plantings."

Over the years he has noticed a marked trend as the Treasure Valley supplanted natural and agriculture lands and riparian areas with houses and other development - raptor numbers are declining, while starling numbers are "increasing grossly."

"The trends are disturbing," he said. "The numbers are looking bad. Birds, for us, are an indicator species. The more diversity of bird life you have the more healthy your environment is."

Cynthia Sewell: 377-6428