Finished projects

Bighorn sheep ram with a curled lip.
Photo credit: Tayler LaSharr

Harvest Records Project

Hunting is an important part of wildlife management, but there is concern over how harvest might affect the size of horns and antlers of ungulate species over time. This project evaluated how the size of horns of hunted bighorn sheep changed through times, and identified the mechanisms that caused change.

Among the 72 hunt areas we studied, horn size remained unchanged in 44, decreased in 19, and actually increased in 9. The researchers found evidence that all three mechanisms caused changes in horn size, depending on the hunt area in question. In fewer than half of hunt areas where horn size declined, evidence pointed to hunting as the cause of evolutionary change. In the others, nutrition and changing age structure appeared to be driving down horn size. In all, current harvest regimes in most hunt areas do not appear to be reducing horn size in bighorn sheep.

A large female moose stands in the open sagebrush, looking directly at the camera. Her coat is thick and healthy, and the sky behind her is a clear blue.
Photo credit: Alex May

Snowy Range Moose Project

Moose have evolved to thrive in cold-weather environments of northern latitudes, but as moose distribution has expanded south in the last century, the warmer temperatures of these regions may be challenging their ability to manage heat stress. The Snowy Range Moose Project, completed in 2019, focused on how the thermal needs of moose at the southern end of their range and how they may be combatting rising temperatures behaviorally.

We found that moose select for bed sites that have cooler temperatures and are either moist or wet as compared to bed sites that were in areas that increased the risk of overheating during the day. As days got hotter, use of standing water and wet grounded bed sites increased. This project conclude that moose are behaviorally mitigating their risk of overheating by seeking out day beds that allow them to lose heat to the ground or the water they are in contact with.

Three male elk with large antlers stand on a grassy hill, morning sun glancing off their coats.
Photo credit: Tayler LaSharr

Sierra Madre Elk Project

Widespread mortality of pine trees following the bark-beetle epidemic can change the ways wildlife and people interact with these formerly intact forest habitats. Elk, for example, rely on intact conifer forests for thermal refuge and escape from predation (e.g., natural predators and human hunters), but as beetle-killed trees fall, the subsequent changes to canopy cover and understory structure can alter forage abundance, thermal cover, and locomotive costs for elk. Behavioral responses of elk to changes in forest structure may, in turn, shift how people hunt them, affecting the way we manage this highly valued species and their habitats.

We found that elk typically avoid beetle-killed conifer habitat, instead choosing to spend their time in intact conifer forests and in grassy meadows. During the autumn hunting season, however elk selected for beetle-killed forests, perhaps as an escape tactic from hunters. GPS tracking of human hunters also showed that hunters were willing to follow elk into and use beetle-killed areas for hunting purposes, particularly when more elk were there.