Tracking Great Basin Rattlesnakes Before and After Prescribed Fire

In the summer of 2023, researchers from the University of Nevada, Reno, working with a National Park Service wildlife biologist, set out to monitor Great Basin rattlesnakes (Crotalus lutosus) at Great Basin National Park, along with the small mammals the snakes eat. They wanted to know where the snakes go during their active summer season and how far they travel from their hibernacula, the dens where they spend the winter.

A before-and-after study

Prescribed burns were planned for the study area in November 2023. The 2023 season provided baseline data from before the burns, so that surveys in 2024 could show how fire changes where the snakes and their prey live.

Following the snakes

From April to October the team captured about 50 rattlesnakes. They chose 19 — 11 males and 8 females — in the Baker Creek watershed and, after anesthetizing them, surgically implanted radio transmitters so their movements could be tracked each week. The most adventurous snake traveled 4.14 miles to and from its den, starting at 7,311 feet and reaching 9,314 feet.

Every snake caught was sexed, weighed and measured and scanned for a PIT tag — a microchip like those used for pets — to see whether it had been caught before. The researchers also took blood and scale-clip samples for genetic study.

Counting the prey

In July the team caught 156 small mammals in live traps set both in the Baker Creek watershed, where burns were planned, and in the Lehman Creek watershed, where they were not — allowing a comparison of burned and unburned areas. Each animal was sexed, weighed, aged and given a numbered ear tag so it could be recognized if caught again. The catch included chipmunks, voles, shrews and a great many deer mice.

Sharing the work

Over the summer the researchers gave campground talks about fire ecology and the role of rattlesnakes in the ecosystem, including in limiting the spread of disease among some small-mammal populations. They also made interesting observations of the snakes feeding, mating and socializing. In 2024 they planned to report more on the relationship between rattlesnakes and their prey and how the prescribed burns affected it.

Sources

• Colton Irons and Kevin Shoemaker (University of Nevada, Reno) and Bryan Hamilton (National Park Service), "Monitoring Habitat Use by Rattlesnakes," first published in The Midden, Great Basin National Park, Vol. 23, No. 2, Winter 2023: https://www.nps.gov/articles/000/rattlesnakehabitatstudy.htm
• The photographs on the source page, credited to individual researchers, are not reproduced.