A research team from Northern Arizona University confirmed the presence of the endangered meadow jumping mouse in parts of Arizona and New Mexico. It’s the first regional survey in a decade, and the team is using ink to find the mice.

They’re using what’s called a “track plate.” It’s a box with an inkpad in the entrance. The mice leave distinct long-toed footprints when they enter the box to eat the bait.

Wildlife ecologist Carol Chambers leads the project. “Because the species are listed as endangered, we are very concerned about the population sizes and we’re looking hard this summer to try to find the animals in as many locations as possible,” she says.

The NAU team found jumping mice in the Santa Fe and Apache-Sitgreaves national forests. The mouse lives near riparian areas and hibernates most of the year. It was listed as endangered in 2014.

The new data will be used to develop a model of the mouse’s preferred habitat, which will inform land management decisions. The U.S. Forest Service has tried fencing off some sensitive riparian areas to keep cattle and elk out.

Earlier this year, the U.S. Fish and Wildlife Service designated 14,000 acres in New Mexico, Arizona and Colorado as critical habitat for the species.