April 5, 2006
Killing wolves that prey on cattle, sheep and other livestock is not an effective long-term strategy for regional wolf control, according to a study by University of Calgary researchers.
The study, Seasonality and reoccurrence of depredation and wolf control in western North America, was published in The Wildlife Society Bulletin. Recently, several U.S. states considered removing the gray wolf from the federal endangered species list after populations that were once extirpated have been re-established.
The study’s findings could lead to changes in how ranchers and government wildlife authorities deal with depredation of livestock by wolves, said lead author Dr. Marco Musiani, assistant professor of environmental design at the University of Calgary.
Using lethal control to limit wolf numbers and curb depredation, said Musiani, requires that 30-50 percent of an area’s wolf population be killed every year. “Killing that many wolves would be difficult,” said Musiani. “If society wants to co-exist with wolves, it has to accept that there will be losses and address the real issue, which is that if ranchers lose some of their animals, or if animals are injured, it costs them money. There are also significant labor costs for increasing livestock surveillance to prevent attacks.”
Musiani cited two alternatives:
- Programs to compensate ranchers for livestock lost to wolves funded by conservationists.
- Activities planned by livestock producers and wildlife officials to prevent wolf attacks during high-predation seasons. These activities may include surveillance by livestock producers, use of guard dogs, fencing, translocation of wolves and the use of wolf repellents.
The study’s authors also noted improving animal husbandry, particularly during high-risk times of the year for livestock.
Musiani and colleagues analyzed wolf attack information for Alberta from 1982-1996 and for Idaho, Montana and Wyoming from 1987-2003. The data demonstrated that tracking and killing wolves that prey on livestock did not result in decreased depredation rates regionally, or over the long-term. Additionally, wolf attacks appeared to follow seasonal patterns reflecting the feeding needs of wolf packs, livestock calving and grazing cycles.
“This study shows that wolves are being killed as a corrective, punitive measure – not a preventative one,” said Musiani. “People hope that killing individual wolves that attack livestock will rid the population from offenders but this isn’t happening. It seems other wolves simply take their place and you have the same problem over and over again.”
Source: University of Calgary.