07/14/2026
On large sheep operations studied across the western United States, 90 percent of livestock kills came from one or two individual coyotes, even when five separate packs held territories on the same property. The other coyotes, the ones sharing the same fences and the same pastures, left the sheep alone.
Ohio State University's Extension wildlife program published that finding in its coyote management guidelines, citing decades of research. The pattern held across multiple studies and multiple states: most coyotes living near livestock do not kill livestock. The depredating individuals are almost always the alpha breeding pair, and usually only during pup-rearing season when the energy cost of feeding a litter drives them to take the easiest available protein. The rest of the resident coyotes hunt rodents, rabbits, insects, and fruit, and they defend their territory aggressively against any outside coyote that tries to enter.
That territorial defense is the part nobody expected to matter.
A bonded coyote pair that holds territory on ranch land and does not kill livestock is, functionally, a livestock guardian. Their territorial behavior excludes other coyotes, including the transient, desperate, and risk-taking individuals that are most likely to attack sheep. Shivik and colleagues documented this in a 2003 study. If the resident pair is not killing livestock, their presence prevents the arrival of coyotes that will. Marcus Webb, a rancher in western Colorado, described the arithmetic: you can maintain one coyote that minds its own business, or you can have five coyotes vying for territory, all taking risks.
The problem begins when someone kills the well-behaved coyotes.
Sacks and colleagues, publishing in 1999, found that snares set to protect sheep preferentially killed non-offending subordinate coyotes rather than the older, wiser breeding adults that were actually doing the killing. The subordinate coyotes were easier to catch because they were less cautious. They were also the territorial defenders whose presence was excluding the real sheep-killers from the property. Removing them opened the territory. The sheep-killing adults, formerly blocked by the territorial structure, moved in and began depredating.
A 14-year USDA study at the University of California Hopland Research and Extension Center confirmed the pattern at scale. Conner and colleagues tracked coyote trapping effort and lamb losses from 1981 to 1995. Their finding was counterintuitive enough that it required the full 14 years of data to be convincing: as trappers worked more hours, more lambs were killed by predators. Not fewer. More. The trapping was removing the territorial coyotes that had been suppressing depredation, and every removal opened the door to incoming animals with no established territory and no reason not to kill sheep.
Oregon State University's Small Farms program titled their summary of the research with a question that captured the disbelief: Using Coyotes to Protect Livestock. Wait. What? Benton County, Oregon, built an entire Agriculture and Wildlife Protection Program around the principle. Instead of contracting with USDA Wildlife Services for lethal removal, the county shifted to non-lethal deterrents, fladry, guard dogs, foxlights, and improved fencing, specifically designed to keep territorial coyote pairs in place rather than destroying them.
USDA's own technical series on coyote damage management notes that coyotes frequently kill in one pasture and never touch the identical animals in the neighboring one. They avoid pastures with guardian animals, heavy human activity, and open terrain where they are exposed. They select pastures near water courses that serve as travel corridors, with brushy cover and broken ground that gives them approach routes and escape options. Every attack is preceded by an assessment. The coyote reads the pasture, the guardian, the terrain, and the risk before it commits. Most of the time it does not commit.
A coyote standing at the edge of a sheep pasture at four in the morning is running a cost-benefit calculation that accounts for the guardian donkey, the fence height, the distance to cover, the number of animals, and the presence or absence of the territorial pair that was there last week. If that pair was trapped and removed last Tuesday, the calculation just changed. The pasture that was defended is now open. The sheep that were protected are now available. The trapper solved a problem that did not exist and created one that does.
Source: Ohio State University Extension / Conner et al. (1998), Hopland Research and Extension Center / Sacks et al. (1999) / Shivik et al. (2003) / Oregon State University Small Farms Program / USDA APHIS Wildlife Services.
