Road Kill Stats Surprise Scientists

April 17, 2008 -- All Dirty Jobs jokes aside: A surprising new study on road kill suggests some species, particularly amphibians, are so often victims of motorists that the phenomenon may help explain the decline of entire populations.

Even the researchers who worked on the study had close calls while counting and identifying mangled animal bodies alongside roads in Indiana, where the research was conducted.

To find their study subjects, the researchers drove slowly in vehicles marked with light beacons, said coauthor David Glista. They worked in two-person teams "so there were extra eyes to observe traffic," he said, adding that there were frightening instances "where we had to question some motorists' skills."

"I didn't want to become one of my own data points," added Glista's colleague, Andrew DeWoody.

The scientists focused their survey on four Indiana roads covering 11 miles, through urban and rural areas. Glista, then a Purdue University researcher who is now a scientist with the Indiana Department of Transportation, and colleagues DeWoody and Travis DeVault counted road kill on the routes twice weekly for over a year. They used a GPS unit to mark locations, also noting the weather and surrounding habitats.

Back at Purdue, they compiled the information into a database and were shocked by the results.

During the survey, they found 10,500 dead animals representing 69 species. Ninety-five percent were amphibians and reptiles, with bullfrogs and other frogs, often too damaged to fully identify, topping the list. The most frequently listed birds and mammals were opossums (79) and chimney swifts (36). The bodies of shrews, skunks, voles, muskrats, mice, raccoons, squirrels, Eastern cottontails, song sparrows, European starlings, American robins, turtles and snakes were also documented.