5-year roadkill effort tracks California's deadliest roads

SAN FRANCISCO — Busy freeways running alongside park land and marshes make San Francisco Bay Area roads a "ring of death" for wildlife, according to a new statewide roadkill report that tracks the deadliest traffic spots for wildlife.

Fraser Shilling, co-director of the Road Ecology Center at the University of California-Davis, used 29,000 volunteer reports of wildlife roadkill over five years to map the most lethal areas for the state's 680 native species of bobcats, barn owls, frogs and other vertebrates.

The idea is to identify stretches that need immediate action to try to protect wildlife — and to make clear the overall toll that California's car culture is taking on native species, Shilling said.

"Just having all the roads and traffic we have is resulting in really big changes in the ecosystem," Shilling said. "It's getting worse as you see more traffic and more roads."

Roadways — which kill not only by collisions with cars but by carving up habitat — are the third-biggest cause of wildlife death, and the biggest cause for some state species, like pumas, he said.

Besides Interstate 80 and California 101 in the Bay Area, where large numbers of wading birds and water birds die, top roadkill spots include San Diego County's California Route 94, which runs through wildlife habitat, and Interstates 80 and 5 in the Sacramento area under the Pacific Flyway migratory bird route.

One way to lessen deaths is to avoid planting roadsides with berries, blooms or other plants that attract wildlife. Highway crossings for wildlife - land bridges are best, but tunnels are more common — help some species, he said.

California's move toward such wildlife crossings is "really far too slow," Shilling said. "We need a 10-year program of 10- to 20 structures a year."

The California Department of Transportation looks at installing wildlife crossings as part of new highway projects, or on stretches of existing road where so many drivers are smacking into animals that it's a threat to driver safety, said Amy Bailey, chief of biological studies at the state agency's environmental analysis division.

Absent threats to driver safety, funding generally doesn't exist to try to ease wildlife deaths on existing roadkill hotspots, however, Bailey said.

Overall, "it's definitely something that the department is working toward addressing," Bailey said.

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Online:

Interactive map for California Roadkill Observation System http://www.wildlifecrossing.net/