Southern Alberta ranchers will soon roundup and move 20,000-plus head of cattle on to timbered government lands in the Rocky Mountain foothills in an annual event that delivers waiting wolf packs with easy, calorie-rich meals.
With calving season over and cattle drive rituals into the high country beginning in June, recently completed research suggests those cows, calves and yearlings will likely make-up a whopping 74 per cent of the “biomass” in an average wolf ‘s summer diet.
That’s the result of a thesis study by University of Alberta student-biologist Andrea Morehouse, supervised by professor Dr. Mark Boyce and recently published in Ecology and the Environment. By studying hair content in wolf scat and visiting kill sites over a year- long period, Morehouse discovered southern Alberta wolf packs switch from a winter diet of wild ungulate prey to domestic stock once its delivered.
Its easy to see why. Herds of slow, plodding cows and calves make easy targets and long lasting meals.
“It surprised me, but not the ranchers,” said Morehouse of her findings of the high percentage preference for summer beef. “There was nothing in the literature that would make you believe it was that high.”
In fact, most previous studies looked only at winter feeding patterns simply because its easier to locate kills and collect droppings on snowy ground. During the winter, when cattle are scarce or non-existent, deer and elk are preferred followed by moose.
Improvements in satellite technology have made it easier for Morehouse to monitor collared wolves and their summertime haunts. Her fridge last year held up to 400 containers of wolf feces collected in the area. A total of 161 kill sites were pinpointed from 698 GPS “clusters” that also included dens and scavenging sites. It’s a relatively simple matter to analyze hair in the collected droppings and discern domestic from wild prey.
Although no one knows precisely how many wolves reside in the Morehouse study area between Waterton Lakes National Park and Chain Lakes Provincial Park, 125 air kilometres due north, ranchers have a good grasp of how many cattle they turn loose and how many return home.
The first major wolf population study in the region, meanwhile, is to begin this summer.
“A lot of cattle that don’t return just end up being classed as missing,” said Morehouse. “One thing that might come out of this is a review of compensation for those missing animals.”
The province now reimburses ranchers 100 per cent of the fall cattle value for confirmed wolf kills and 50 per cent for likely kills. But it offers nothing for “missing” animals; some of which may be the victims of illness or accident or the targets of rustlers and poachers. It’s believed between one and two per cent of the free-range cattle go missing each year, but documented loses are ambiguous.
Last year 37 per cent of all reimbursement payments, approaching $150,000 for livestock depredation claims, were sent to this area, which comprises less than three per cent of Alberta’s landmass. All compensation monies come from hunters who purchase Alberta licenses and not general revenues.
The livestock “grazing season timing coincides with wolf pup rearing season,” notes Morehouse’s thesis report. “And the nutritional demands of wolves are considerable during this period due to the need to satisfy growing pups.”
The report also shows scat analysis “only reveals what the wolves ate and not necessarily what they killed.” A lot of scavenging, especially in “boneyards” takes place year-round.
Boneyards are out of the way locations where ranchers haul livestock carcasses. Animals that die of natural causes used to be hauled away by rendering processors who paid for carcasses. But that practice was halted for health reasons with the discovery 10 years ago of BSE, commonly known as Mad Cow Disease.
While local rural municipalities contemplate funding for an enclosed carcass composting plant, many carcasses are being dumped in open pits or scattered across the landscape to be scavenged by birds and mammals, a practice allowed by the province.
The result has been increased use by both wolves and grizzly bears. In fact, private lands with boneyards, on the edge of the Alberta forest reserve, have been declared “hot zones for grizzly bear encounters” by a paper recently published in The Animal Conservation Journal. More than 300 grizzly incidents involving humans and livestock have been recorded on these ranchlands during the past 10 years and the number is rising according to the Journal.
The Morehouse findings also surprised provincial range and land managers as well. “We knew it occurred but not to that degree,” said Mike Anderson of Alberta Sustainable Resources.
“The percentage is shocking; its higher than I would have imagined,” added Rob Dunn of Alberta Agriculture.
In Alberta wolves can be hunted year round with no limit on the number of animals taken. Trapping is allowed from November through February. Still it appears their number remains constant, or according to local ranchers, is more likely growing. The study area remains the eastern slope of a major carnivore travel corridor between Banff and Glacier National Park in Montana.
Blaine Marr, a third generation local rancher and Western Stock Growers Association board member, says his organization doesn’t want a wolf-free zone, but does want numbers kept in check. Among other things, he’d like to see the trapping season run through the end of March.
Earlier this year the association held a trapping seminar that was fully booked months in advance. “Interest is at a peak,” he says. “A wolf is the hardest animal there is to trap. They’re exceptionally smart, and even the most skillful trapper has a difficult time.”
Prime pelts sell for up to $350.
“We don’t want the landscape wiped free of wolves, but at the same time we don’t want packs of 10 or 12 that can kill anything that crosses their path.” †