Hunting for roadkill data

08/02/2012

If you’ve driven through Bear Valley much this summer, chances are you’ve seen deer crossing the road. And you might have passed dead deer, and perhaps more disturbingly, dead fawns. With well over 1,000 black-tailed deer in Point Reyes National Seashore, seeing struck animals comes as no surprise. What might be surprising is the sight of seashore bio-technician Tim Bernot snapping a photograph of the same fresh roadkill.

This isn’t art; it’s documentation. Mr. Bernot has devoted the last several weeks to keeping count of every deer strike in and around the seashore. During the day he’s busy observing elk and searching for non-native fallow deer that survived extermination, but when Mr. Bernot gets a call via radio about a road-struck deer, he gets in his truck, drives to the animal, and takes a few photos of its remains. He captures a familiar landmark in the background, or, if the location is ambiguous, he notes its GPS coordinates. He is gathering a new body of roadkill data.

“It’s something that the park decided to work on so that in case we want to do something about this with the county, then at least we’ll have something to show,” Mr. Bernot said. “Nobody wants to come to Bear Valley Visitor Center and see a dead deer on the road, so we try to prevent that.”

While 2010 and 2011 have been better years for black-tailed deer, 2009 was a blood bath, according to Mr. Bernot. Summer is an especially common time to find deer near roads. “Deer probably don’t recognize crossing the road as something dangerous. All they’re concerned with is getting from one point to another for food, water, bed site or any other resource,” University of California, Davis research biologist Dr. Dirk Van Vurten said. “[And] as summer progresses in California, food quality declines dramatically and deer might have to look more widely for food and water sources.”

Still, Mr. Bernot believes deer strikes can be mitigated, and that one of the best ways would be by replacing the standard deer-crossing sign posted on Bear Valley Road. “Signs generally are not effective. The only time people will slow down at all is if the sign is flashing or if it is a mobile sign,” Fraser Shilling, director of road ecology at Davis, said. Mr. Shilling, who is currently working on a study of black-tailed deer movement around I-280, says flashing and mobile signs have been proven to slow drivers by at least three miles per hour.

Researchers at Davis and elsewhere are also studying the effectiveness of animal detection systems—equipment that alerts drivers as animals near the road.

Fences throughout the seashore are one reason Mr. Bernot believes deer fall victim to road strikes. Just weeks ago, after noticing several deer popping out of an area near the seashore’s headquarters, he saw a hazard. “The gate was funneling them away from the shoulder area where drivers could more easily see them,” Mr. Bernot said. Since then he and other rangers removed the remnant gate, as well as other unused fences, which Mr. Bernot believes were stopping deer from moving quickly across roads.

Fences in private backyards, particularly mesh fences, are also problematic. Once Mr. Bernot saw two fawn idle on Highway One near Dogtown, so he stopped to slow traffic for them. “They kept trying to get through [the fence], banging their heads against the mesh and bouncing back to the road,” Mr. Bernot recalled. “A deer will come to a fence and turn back and walk back to another one on the other side, and panic, causing [it] to run back and forth.” A barbed wire fence would allow deer to pass through, he said.

But while seashore employees have worked diligently to remove fences, Mr. Shilling said the answer to fewer strikes might just be more fencing. “In order for this to work the fence would have to be complete. When you have that, then you have a pretty effective method. Most animals, including deer, would be put off by an eight-foot fence,” he said, adding: “But they have to have an alternative walking route. There has to be a place for them to cross.”

The fences Mr. Shilling envisions would guide deer to an undercrossing, a place where animals could safely cross beneath roads. But such a project comes with a big price tag—placing an undercrossing under a two-lane road like Bear Valley or Highway One would cost over $100,000, Mr. Shilling estimates—so he suggests more economically friendly alternatives. “There are existing places where streams go under highways. If you can utilize the places where roads are already made permeable and make them wildlife-crossing friendly, it’s an affordable alternative.”

Perhaps the main factor responsible for road strikes are speeding drivers. “Commuters use Bear Valley as a short cut from Olema to Inverness,” Mr. Bernot said. “When people are commuting in the evening and the morning, that’s when deer are most active.” Although most people probably don’t notice the deer sign, a large number of people also seem to not notice the speed limit. “If people complied with the speed limit they would at least have a chance to see [the deer] and stop,” he said.

Furthermore, Mr. Bernot claims Bear Valley Road is no shorter than the alternative route, Levee Road.

Mr. Bernot hopes the community will speak up on the issue. “I’d love to see some sort of community-action committee do a campaign or something to get the word out,” he said. And if not for the safety of the animals, for their own welfare. “You might not only kill a great animal, but yourself,” he said.

According to the U.S. Department of Transportation, white-tailed deer kill around 130 Americans each year in car accidents. In the worst of years, 1994, 211 people were killed. And the 1.5 million annual deer collisions cost Americans more than $1 billion in insurance claims. “I myself hit a vulture once. There was a dead deer on the side of the road and I just hit it dead on,” Mr. Bernot said. “It cost me $250 just to get a new grill.”