The primary threat to the persistence of many of the world’s canid populations is human intolerance related to livestock predation. The applied aim of this research, which began as my Masters Thesis work, has been to encourage predator management strategies that facilitate coexistence of carnivores and humans in agricultural landscapes. Specifically, my colleagues and I used radiotelemetry of coyotes in sheep-producing regions to study the ecological context of carnivore predation on livestock. We found that a small proportion of the population was responsible for most sheep predation and that these individuals also were the least likely to be affected by standard predator control methods. This study system also presented opportunities to investigate several questions of basic ecological significance, including life history, foraging ecology, and interspecific relationships among meso-carnivores.

Ben Sacks radio-collaring a coyote (left); sheep in pasture at Hopland Research and Extension Center (center), Jennifer Neale radio-collaring coyote (right)

Collaborators
Jennifer Neale (American River College), Karen Blejwas (ALaska Fish and Game), Mike Jaeger (USDA/APHIS/WS/NWRC), Dale McCullogh (UC Berkeley), Gary Johnson (USDA/Wildlife Services), John Poor (rancher and brilliant naturalist), Hopland Reserach and Extension Center staff

Funding
This research was funded primarily by USDA/APHIS/WS/National Wildlife Research Center, as wells as Graduate Student Fund of the Dept. of ESPM at UC Berkeley.

Publications

Sacks, B. N., and J. C. C. Neale.  In Press. Coyote abundance, sheep predation, and wild prey correlates illuminate Mediterranean trophic dynamics.  Journal of Wildlife Management.

Sacks, B. N., and J. C. C. Neale. 2002. Foraging strategy of a generalist predator toward special prey: sheep in the coyote diet. Ecological Applications 12:299-306.

Blejwas, K. M., B. N. Sacks., M. M. Jaeger, and D. R. McCullough. 2002. The effectiveness of selective removal of breeding coyotes in reducing sheep predation. Journal of Wildlife Management 66:451-462.

Jaeger, M.M., K.M. Blejwas, B.N. Sacks, J.C.C. Neale, M.C. Conner, and D. R. McCullough. 2001. Targeting alphas can make coyote control more effective and socially acceptable. California Agriculture 55:32-36.

Neale, J. C. C., and B. N. Sacks. 2001. Food habits and space use of gray foxes in relation to sympatric coyotes and bobcats. Canadian Journal of Zoology 79:1794-1800.
Sacks, B. N. and J. C. C. Neale. 2001. Does paternal care of pups benefit breeding female coyotes (Canis latrans)? Southwestern Naturalist 46:121-126.

Neale, J. C. C., and B. N. Sacks. 2001. Resource utilization and interspecific relations of sympatric bobcats and coyotes. Oikos 94:236-249.

Sacks, B. N., M. M. Jaeger, J. C. C. Neale, and D. R. McCullough. 1999. Territoriality and breeding status of coyotes relative to predation on sheep. Journal of Wildlife Management 63:593-605.

Sacks, B. N., K. M. Blejwas, and M. M. Jaeger. 1999. Relative vulnerability of coyotes to removal methods on a northern California ranch. Journal of Wildlife Management 63:939-949.

Neale, J. C. C., B. N. Sacks, M. M. Jaeger, and D. R. McCullough. 1998. A comparison of bobcat and coyote predation on lambs. Journal of Wildlife Management 62:700-706.

Radiotelemetry was done using both handheld antennas (left, Jennifer Neale) and permanent stations (right); Female coyote 104 shown with green collar (center)