There are many answers to the riddle of why moose, elk, and deer cross roads. But the mystery WCS scientists are trying to solve is where these large mammals choose to cross.

In an attempt to decrease car accidents along U.S. Route 20 in Idaho, the researchers are radio-collaring moose and elk and tracking their movements via satellite. Called “the longest Main Street in America,” Route 20 was the scene of almost 170 collisions with moose, elk, mule deer, and white-tailed deer between 2005 and 2009. 

Determining how wildlife travels through the region and how species interact with the road will make the highway safer for the animals and for the people driving on it.

“Roadways are one of the biggest threats for wildlife populations in the twenty-first century,” said Jodi Hilty, program director for WCS-North America. “Fortunately, advances in the science of road ecology, as well as new tools, can help us address both greater human safety and wildlife conservation priorities in new and existing roadways.”

The moose and elk's GPS-collars will reveal the animals’ migration paths and preferred road-crossing points as they journey from their wintering grounds in Idaho’s St. Anthony Sand Dunes and Sand Creek Wildlife Management Area to their summer feeding grounds in the Island Park Caldera and Wyoming’s Yellowstone National Park. Citizen scientists are also volunteering to map the animals’ movements, but in the old-fashioned way. They will scan the roadway for hoofprints and other animal tracks and report the wildlife they see from their car windows—hopefully, at a safe distance.  

“This will be the most detailed data ever collected on elk and moose in the Sand Creek/Island Park area of Idaho,” said Shane Roberts, a wildlife biologist for Idaho Fish and Game. “It should provide a wealth of information on seasonal movements, survival, behavior around roadways, and road crossing sites that will be used to better manage these species and improve human safety along U.S. 20.”