Dan Ray is always among the first people to spot the bighorn sheep that come down from the Black Hills each year during their winter mating ritual along the western fringes of Canyon Lake.
"It's just an 'oh wow' deal," said Ray, an avid sheep-spotter who starts his search for the bighorns in November every year. "I just love the way they look; it's a wonderful animal."
But this year's search proved challenging for Ray and other local sheep enthusiasts, who say they are seeing fewer of the sheep and less often.
Many are noticing the thinning herd's hacking cough — a symptom of the pneumonia that recently has killed almost half of the state's bighorn sheep lambs, according to officials with the South Dakota Game, Fish & Parks Department.
Another 28 percent of the state's bighorn lambs are killed by predators, a figure that also is boosted by the sickness because it makes the lambs weaker and easier to catch.
"We're still having pretty bad effects from the pneumonia," Game, Fish & Parks Wildlife Biologist Lauren Wiechmann said. "Most of the rams and ewes are able to survive. They can build up an immunity in their body to fight off the pneumonia. Our population is trending toward the older generation so we only have a couple yearling rams coming up a year and very few yearling ewes."
The aging aspect of the bighorn herd means that very few newborns survive to replace the older, dying sheep. The result is a progressively smaller herd, which will make spotting the majestic horned sheep even harder in the coming years.
Wiechmann said there is no current treatment for the pneumonia, aside from a newer vaccine that's being tested in labs and surrounding states with bighorn populations.
"Once it's in our wild population, we can't get rid of it. It's there for good," she said, adding that other states see large die-offs but herds sometimes rebound. "A couple years down the road it may turn the corner and we get rams back again but we're not quite around that corner yet. So really, it's kind of hope and wait."
But even with a new treatment, Wiechmann said, inoculating the state's wild population is difficult. She said it's hard to ensure every bighorn gets a shot and that others don't get double-dosed.
The Rapid City herd of around 55 to 80 bighorn sheep includes the 35 to 40 animals that gather near Cleghorn Canyon west of Canyon Lake, and another herd near Spring Creek south of Sheridan Lake Road. There are four known bighorn herds statewide.
South Dakota overall has between 275 and 300 bighorn, which were believed to have been hunted to extinction in the state by 1916, according to Game, Fish & Parks. The department began reintroducing bighorn in 1990.
Wiechmann said an exact number of the bighorn suffering from pneumonia is hard to tell, but she said the majority of them are carriers of the bacteria that causes it.
GF&P suspects that the bacteria Mycoplasma ovipneumoniae (M. ovi) predisposes wild bighorn to pneumonia. Once the sheep are infected with that strain of bacteria, other normally harmless strains in the sheep's nose, throat or gut are believed to descend into the animal's lungs and cause the disease, according to the department.
Wild bighorn get M. ovi from making contact with domestic livestock.
For Ray, it's disappointment to see the wild bighorn suffering. He's hoping that the sheep will make a rebound so he and others can continue to marvel at the annual spectacle.
"If people don't go out and look at them, they're really missing something," he said. "I just really appreciate looking at them."
[Editor's note: Due to erroneous information from the Department of Game Fish & Parks, this story has been changed to reflect a correction. Bighorn sheep are native to South Dakota but were believed to have been hunted to extinction by 1916. The department began reintroducing bighorn in 1990.]