Mining for Bats

Mark Hayes

Mark Hayes spent time researching abandoned mines that led to an article on hibernation sites of Townsend big-eared bats. Photo by Lea’ R. Bonewell

University of Northern Colorado doctoral student Mark Hayes recently completed a multi-year study that helps identify attributes of abandoned mines that attract a species of bats in southwest Colorado.

Hayes examined nine years’ worth of data, including conducting fieldwork in the mines, in co-authoring the most thorough article to date on hibernation sites of Townsend’s big-eared bats, a species of conservation concern. The article appears in the current edition of the Journal of Wildlife Management.

The research is being used by wildlife managers to inform them of abandoned sites that should be considered in preserving winter habitats for the species. The research recommends conducting winter surveys of abandoned mines before deciding on closures or reclamations.

“Abandoned mines are dangerous places, and Colorado has been trying to close unsafe sites, but at the same time looking for important bat roosts and saving those sites used by species of conservation concern,” Hayes said.

Townsend’s big-eared bats were found in 33 of the 138 abandoned mines surveyed, with nearly all of the bats hibernating independently. Sites with more than one opening and temperatures near zero-degrees Celsius were more likely to serve as winter homes.

“We haven’t found large groups of Townsend’s big-eared bats hibernating in abandoned mines in southwestern Colorado,” Hayes said. “This is surprising, as we are beginning to wonder if there are any large congregations in Southwestern Colorado and if so, where are they?”

Hayes’ interest in the research piqued after completing his bachelor’s degree in Environmental, Population and Organismic Biology at the University of Colorado at Boulder. That’s when he volunteered with the Colorado Division of Wildlife to conduct bat surveys at abandoned mines — a project that led to meeting his wife, Lea’ Bonewell, who has chronicled his fieldwork through photos, including the one above.

“As I became more and more involved with this project, I realized that there were a lot of unanswered questions about the ecology and conservation of bats in Colorado,” Hayes said.

Hayes’ advisor is Professor Rick Adams, an authority on bats in his own right (see story).

“Perhaps one of the key events that inspired me to become a bat biologist was attending one of Rick’s talks,” Hayes said. “He was funny and very knowledgeable. He helped me realize that bats were extremely important from an ecological perspective.”

- Nate Haas