Fish, Wildlife & Parks, with assistance from North Dakota Game and Fish and Wyoming Game and Fish departments, trapped 39 bighorn sheep from the Missouri River Breaks earlier this month to supplement wild sheep populations in the two neighboring states.
The operation was conducted on the north side of the Missouri River by a team of wildlife-capture specialists, who netted the sheep from a helicopter, hobbled and blindfolded the animals, then flew them to a staging area where they were inspected by wildlife veterinarians, radio-collared and then loaded into livestock trailers for their journey to new habitats.
Twenty sheep, 14 ewes, 3 yearling rams and two male lambs, were captured in the Mickey and Brandon Buttes area in Hunting District 622, in southern Phillips County. Nineteen of those animals were transported to North Dakota’s Little Missouri River. One of the sheep, a mature ewe, suffered a broken back during the netting operation and was euthanized at the staging area.
“We were certainly sorry to lose an animal,” said Mark Sullivan, FWP wildlife biologist in Malta who coordinated the District 622 capture operation. “But one sheep in 40 isn’t surprising. We did a complete necropsy on the ewe and collected valuable information that will help us determine herd health.” All the other captured sheep made it through the capture and transportation to the release site in healthy condition.
Another 20 sheep, 13 ewes, 2 yearling rams, two male lambs and three female lambs, were captured in Hunting District 680, in the Cow Creek area of southern Blaine County. Those sheep all survived the operation and were transported to Wyoming’s Bighorn Canyon, supplementing a population of bighorns in the rugged country east of Lovell.
Sullivan credited cooperation not only from the sister state wildlife agencies but also personnel from the Charles M. Russell Wildlife Refuge and Bureau of Land Management who assisted in the operations.
“We don’t do these operations very often so it’s a great opportunity to not only work directly with wildlife but also with our counterparts in other agencies and states,” said Sullivan, who noted that removing some sheep from the Missouri Breaks population will benefit those left behind.
“Our best sheep habitat is filled and we are worried about habitat degradation and disease transmission,” says the biologist. “Sheep are very susceptible to disease when densities get too high and habitat quality declines. Plus, when habitat fills up, wild sheep have a tendency to roam, which means they have more chance of coming into contact with domestic sheep and transferring disease back to wild sheep populations.”
Al Rosgaard, FWP wildlife biologist based in Havre, said the Breaks sheep herds are managed to maximize recreational opportunities.
“We offered 15 either-sex hunting licenses in District 680 and 4 either-sex licenses in District 622 this past year,” says Rosgaard. “We also issued 30 ewe licenses for District 680. Each year some fine trophy rams are taken in both these hunting districts.”
A total of 174 bighorn sheep were counted in District 622 and another 434 sheep in District 680 during annual censuses in the Missouri River Breaks. Sullivan noted that at best only 75 percent of the sheep are observed during these surveys, so the actual population totals are higher.