Wolf meal habits change with grazing season

Customers return to restaurants where they liked the food.

However, repeat visits are not exactly welcome when the customers are wolves and the food is the livestock bone yard.

“If you follow a wolf pack, they will systematically go from bone yard to bone yard to bone yard,” said University of Alberta biological sciences researcher Mark Boyce.

Boyce and his assistants, Andrea Morehouse and Joe Northrup, have been studying wolf activity in southwestern Alberta, specifically an area along the eastern slopes between Waterton Lakes National Park and Chain Lakes Provincial Park.

They found that wolves kill more cattle in the region than grizzly bears and cougars.

“Wolves are the real culprits and have been the biggest problem as it relates to beef producers,” Boyce told a Beef Cattle Research Centre webinar Nov. 17.

He and his team put GPS collars on wolves and tracked their activity using a “cluster analysis” of where packs spent their time, combined with a scat analysis to see what the wolves ate.

Their studies of 698 wolf clusters found that cattle made up 45 percent of wolves’ prey during the grazing season, followed by deer at 22 percent, elk at 13 percent and moose at nine percent.

Cattle made up 12 percent of wolves’ prey during the non-grazing season from the end of October to the end of May, compared to 37 percent deer, 23 percent elk and eight percent moose.

The rest of the wolves’ food, in both the grazing and non-grazing seasons, comprised scavenging and smaller prey that is difficult for researchers to measure.

“The most predominant prey of wolves during the grazing season … were cattle, and it’s actually more pronounced than as illustrated here because cattle weigh a lot more than these other prey,” said Boyce.

Put another way, cattle made up 74 percent of the biomass that wolves ingested during the grazing season.

There are 6,000 to 7,000 wolves in Alberta ,and ranchers are allowed to deal with them if they become a problem. There is no hunting season or limit on the number of wolves that can be trapped or shot by ranchers.

Compensation is available for ranchers who lose livestock to a proven wolf kill.

Southwestern Alberta ranchers make up 37 percent of all paid claims for kills by large carnivores, even though they occupy only three percent of the land base.

That shows the frequency of interaction in this area where the mountains and the prairie meet.

Boyce said his research showed 85 percent of wolves’ scavenging activity centres on bone yards, which is where ranchers put their dead stock.

Those sites are also major attractants for grizzly bears.

Incidents involving both types of large carnivores increased in Alberta after 2003, when tighter BSE regulations made it more ex-pensive to render dead animals.

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