Raccoons, deer, cats, birds, turtles, even humans - all will make tracks under busy highways when they can, or must.

That's the upshot of a fun but practical new study from the Appalachian laboratory of the University of Maryland Center for Environmental Science.

Researchers spent more than two years capturing critters on infra-red cameras as they moved through 265 different road and highway culverts around the state. They tallied up 57 different species using the underground structures, many of them put in when the road was built merely to channel a stream from one side to the other.

“I was surprised at the sheer number of species using these culverts, from birds to reptiles to mammals,” study author Ed Gates said in a release. 

The critter caught most frequently by far on the cameras was the northern raccoon, followed by common house cats and then white-tailed deer.  But barn swallows, mallards and great blue heron were up there, too. So were humans, oddly or naturally enough.

The study was done for the State Highway Administration so they can figure out how to get more animals to use the culverts. It enables wildlife to move about in habitat increasingly carved up by pavement and avoid becoming roadkill - or worse, killing or maiming motorists.

I wrote about this effort a year ago in the Baltimore Sun.  You can read that story here.  And to see some more "wildlife candid camera," check out UMCES on Facebook.

(Photos courtesy University of Maryland Center for Environmental Science)