Abstract 286 – Low-stress herding reduces cattle predation by grizzly bears

Matt Barnes

A conservationist partnered with two grazing permittees and the Shoshone National Forest on
the Union
Pass Allotment, in the Wind River Mountains of northwestern Wyoming, USA, to improve cattle
management, and by extension maintain land health and reduce conflicts with wildlife,
particularly grizzly bears, which had killed several cattle each year, and gray wolves. The group-
size effect is a well-known anti-predator behavior of many prey species, including ungulates.
Strategic rotational grazing increases stock density (concentration), and low-stress livestock
handling increases herd instinct--two parallel ways to facilitate the group size effect in livestock.
The Forest Service developed a grazing plan that involved combining the two herds, and
rotation through 7-9 grazing management units but only one cross-fence. Prior to the project,
the cattle did not form a single herd, self-segregated into small social units, and in some cases
repeatedly traveled down from the mountain allotment to their home ranch. We-cohosted
training in low-stress livestock handling, and for 3 years the permittees applied low-stress
herding to the best of their ability. The cattle formed larger groups but never formed a single
cohesive herd. In the 3 years prior to the project, there was predation by grizzly bears every
year; during the 3 years of the project, there was no confirmed predation. One herd reduced
annual confirmed losses to bears from mean 2.6% (maximum 6.7%) to 0%; losses to unknown
causes from 3.9% (maximum 7.9%) to 2.0%; and total losses from 10.6% (maximum 19.1%) to
4.3% per year. (The other herd did not have adequate records of pre-project losses.) In this case
study we cannot rule out other factors, but it appears likely that low-stress herding in a
strategic rotation led to reduced bear-livestock conflict. Strategic grazing management and low-
stress herding may be important aspects of a strategy for reducing livestock vulnerability to
predation by large carnivores.