If mass wildlife die-offs this harsh winter elsewhere in the Northwest are pretty clear cut, one west of Yakima is a bit more of a mystery.
But why 10 bighorn rams starved in close proximity to each other on Cleman Mountain is less clear.
The carcasses were found on the long basaltic anticline above Naches in late winter by a hiker, who alerted the Washington Department of Fish and Wildlife, which included the news in their latest Wildlife Program report.
Two game wardens, another staffer and district game biologist Jeff Bernatowicz went to the scene, collecting the heads of eight of the rams (two other heads apparently were missing) as well as samples to test for a type of pneumonia that’s hit wild sheep herds hard elsewhere in the state.
Bernie says the results came back negative for the Mycoplasma ovipneumoniae bacteria.
That was “good news,” he wrote in an email, as one nearby herd that was infected had to be entirely destroyed and the Cleman sheep have become, more or less, WDFW’s seedstock for replenishing California bighorn herds elsewhere in Washington.
So why did the rams die?
Though the carcasses were in rough shape for postmortems after lying around for some time, Bernie’s best guess is starvation.
Coming out of the fall rut likely in a weakened condition, the rams faced what became a very snowy and cold, lingering winter.
“Some bighorn sheep seem to be faring poorly due to the winter conditions,” a WDFW Feb. 6 report states.
But here’s where it gets a little odd:
The ten rams were just a mile from a well-used feeding site in the valley, the biologist says.
In January it saw as many as 275 bighorns, according to a Yakima Herald article, but for some unknown reason, these and other rams stopped hitting it that month.
“Exactly why they didn’t opt for pellets/hay is a mystery,” Bernie says.
Indeed, but the Evergreen State’s wild sheep populations have proved perplexing in the recent past.
A sudden decline seen in the Sinlahekin herd of northern Okanogan County was answered a couple years later by a sharp increase that was believed to be due to shifts in range usage but also possibly emigrants that subsequently became immigrants.
Back on Cleman Mountain, through mid-March, at least 15 rams have died, and Bernie says the crew observed dead ewes as well.
“There are likely other mortalities,” he adds. “It’s a big mountain and we aren’t out searching. The Clemans herd has typically produced plenty of lambs, so should rebound quickly, unless there is an unknown pathogen in the herd.”
Bernatowicz says it would have been better to keep the herd within the 170- to 220-animal range through the use of special hunting permits, but as it stands, between this die-off and translocation of 23 to the Quilomene and Vulcan Herds this past January, the wild sheep are still within population objectives.