As oil washes ashore along the Gulf Coast, the Cornell Lab of Ornithology is asking birders to keep an eye on nesting birds -- not just near water, but hundreds of miles inland.

"Wildlife biologists are monitoring species such as pelicans and plovers in the immediate path of the oil," said Laura Burkholder, an extension specialist at the Cornell Lab of Ornithology. "But we need bird watchers across the country to help us find out if birds that pass through or winter in the Gulf region carry contamination with them, possibly creating an 'oil shadow' of declines in bird reproduction hundreds of miles from the coast."

To help, Burkholder said that anyone with an interest in birds can learn how to find and monitor nests as part of the Cornell Lab's NestWatch project. It involves visiting a nest for a few minutes twice a week, and recording such information as how many eggs it contains, how many chicks hatch and how many leave the nest.

"Many birds that nest in backyards all across North America, such as red-winged blackbirds and tree swallows, spend part of the year along the Gulf of Mexico, where they could be affected by the oil spill," Burkholder said. "Toxins often have profound effects on reproduction, and it's possible that toxins encountered in one environment can affect the birds in another environment, after they arrive on their breeding grounds."

When participants across large regions contribute information, Burkholder said, scientists can assess changes in nesting success in relation to such environmental factors as habitat loss, climate change and pollution.

Citizen-science participants have helped the Cornell Lab monitor the success rates of nesting birds for 45 years. Now, Burkholder said, it's especially critical to capture data on nesting birds to reveal the health of birds before they encounter the oil spill -- as well as in the years ahead, to detect possible long-term effects.

To help the effort, visit http://www.nestwatch.org. In addition to accepting observations from the general public, NestWatch is available as a data repository for wildlife agencies and scientific organizations to support their research on the impacts of the oil spill.