There are some new kids on the block at the Old Man on His Back (OMB) Prairie and Heritage Conservation Area that will help to bring vitality and diversity to the bison herd.
The Nature Conservancy of Canada (NCC) is adding five young bison bulls to the herd as part of a revised management plan to grow the herd.
The bulls have already arrived at OMB and will be integrated with the herd during the annual roundup, when the herd is moved to their winter pasture.
“It will definitely shake things up a little bit, because the existing bulls in the herd are all quite a bit older than these ones,” NCC Program Director for Southwest Saskatchewan Michael Burak said. “We don't anticipate that they'll consider them to be too much of a threat necessarily. … There definitely will be a couple of squabbles here and there. It will really depend largely on the attitude of the five that we just brought in. If they're really trying to push boundaries and trying to test some of those older animals, they'll be put in their place pretty quickly.”
The introduction of the young bulls during the annual roundup is done on purpose to make their arrival less noticeable, because there is a lot of movement and change during the herd’s shift from the summer to winter pasture.
“Everybody is a little bit confused and there was a really big kind of change and a shift that happened,” he said. “They all go through a handling system. So they're all a little bit stressed out. It's kind of the perfect time to just push everybody out into their winter pasture at the same time and hopefully they will not notice that there's all of a sudden these extra individuals that weren't there previously.”
The five bulls arrived about a month ago. They were released into a separate paddock to give them time to adjust to their new surroundings and their health can also be monitored before their introduction to the herd.
The date for the roundup will depend on when the herd decides to come into the corral, which usually only happens when there is already a good snow cover and they can be attracted with bales of hay.
All five bulls were born in 2017 and they are around two-and-a-half years old. They were born and raised in Canada, but their lineage can be traced back to the northern United States, including the bison herd at Theodore Roosevelt National Park in North Dakota.
They came from three different producers. Three are from different areas of Saskatchewan. Two are from a producer in the Prince Albert area and another one was obtained from a producer near Shaunavon. Two came from a producer in central Alberta.
The OMB herd is genetically pure plains bison and the new arrivals were evaluated to confirm they are also the same. Genetic samples were submitted to the University of California, Davis, where tests were done to determine the presence of any cattle genes in those animals. The Alberta producer has done regular genetic tests on his herd, and he picked bulls that he knew are genetically pure.
These bulls will have a lot more space to roam when they join the herd on the vast plains of the OMB conservation area.
“I think it's definitely going to be a bit of a change for them,” Burak said. “They may not be used to having quite as much open space, but I don't think it would be too big a transition for them. Normally with bison, they tend to just want to stick socially close to each other.”
The OMB conservation area covers 13,088 acres (5,297 hectares) and is located in the R.M. of Frontier, 15 kilometres west of Claydon and 210 kilometres southwest of Swift Current. NCC manages OMB as a working ranch, and the bison will graze on about 9,000 acres of land. The remaining 4,000 acres are used for annual grazing by about 200 cattle from around 11 neighbouring ranchers from early June to mid October.
“We're really pleased with how the whole bison introduction and the bison program have been going,” he said. “We're definitely achieving the goals that we set for ourselves as far as keeping the property healthy and making sure the grass is nice and productive, and that it is being grazed in a sustainable way. We're really proud of the way that we are able to showcase the differences or the similarities as well between cattle and bison grazing.”
The original introduction of a group of 50 two-year-old plains bison to the OMB conservation area took place in the winter of 2003. They came from Elk Island National Park in central Alberta. There were 25 males and 25 females, but over time the NCC staff realized this 50 per cent split between the two sexes did not work. There were too many male animals, and over time the composition of the herd was changed.
There are currently seven adult bulls (excluding the five new arrivals), 68 adult cow, and nine calves (six yearling heifers and three yearling bulls) that were kept back from the previous calving. The introduction of the five young bulls will help to diversify the genetics of the herd and the goal is to increase the size of the herd to about 100 breeding individuals.
“We've been in the process of rewriting a management plan for that herd for probably the better part of a year now to shift towards managing them in a more natural kind of way,” Burak said. “That would involve the herd being larger for one, as well as we'll have more breadth within our age classes. Right now, the majority of our herd is about 10 years old and older, whereas in a natural herd you would probably have your largest age class from about four to eight years old and then you would have a continuum of younger animals and then some older.”
The easiest and least expensive way to grow the herd will be to just keep their own calves back every year, but that will have a potentially negative effect on genetic diversity.
“If we're keeping calves with only our current herd bulls left in there, then we have a pretty good chance that they'll actually end up bred back to their relatives or even their fathers,” he explained. “That's why we brought five more in so that we have a bit more variation and we can spread that out a bit more and dilute the effect of any inbreeding that we might see.”
NCC staff still need to do more work to evaluate the carrying capacity of the conservation area as part of the implementation of the revised management plan. They will look at the kind of grass production on the property and that information will be compared with data on the forage needs of bison. They also have to take into account the needs of other foragers, and they will calculate the natural grazing rate of other wild ungulates such as deer.