Predators May Be To Blame For Recent Moose Calf Survival Issues In Part of NE WA

Washington wildlife managers looking into how a growing suite of hungry predators are affecting deer, elk and moose populations believe a Shiras subherd in the state’s northeast corner bears watching.

WDFW reports an unusual signal seen in moose calf survival in east-central Stevens and southern Pend Oreille Counties in recent years.

A WDFW MAP SHOWS TWO MOOSE STUDY AREAS, THE NORTHERN ONE OF WHICH SAW LOWER CALF SURVIVAL THAN THE SOUTHERN ONE. (WDFW)

It was lower in back-to-back years than in a study area just to the south and a cause for concern, biologists say.

“Calf-survival in the northern area, particularly during 2014, was low enough to elicit concern for population stability,” note authors Brock Hoenes, Sara Hansen, Richard Harris, and Jerry Nelson in the just-posted Wildlife Program 2015-2017 Ungulate Assessment.

They’re not sure why that is, except to say it’s probable some — maybe all — of the calves in question ended up as dinner and that more study will help flesh that out.

“Calf mortality occurred irregularly, with no discernible seasonal concentration,” they report. “We are unable to attribute specific causes to any of the calf deaths (the study is not designed to attribute specific causes to any of the calf deaths). That said, it is likely that at least some of the calf deaths were caused by predators.”

Among the toothsome crew roaming this country are cougars, black bears, perhaps a grizzly or two, and wolves.

According to WDFW’s latest wolf map, the Carpenter Ridge, Dirty Shirt, Goodman Meadows and Skookum Packs occur entirely or partially in the northern moose study area, and  all of which were successful breeding pairs in 2016. And in the past the Diamond wolves were here too.

A CLOSE-UP OF WDFW’S MARCH 2017 WOLF MAP SHOWS PACK LOCATIONS. THE NORTHERN MOOSE STUDY AREA OVERLAPS ALL OR PORTIONS OF THE DIRTY SHIRT, GOODMAN MEADOWS, CARPENTER RIDGE AND SKOOKUM PACKS. (WDFW)

By contrast, in the southern moose study area — Blanchard Hump and Mt. Spokane — there are no known packs, or at least were at the time of the biologists’ review last December.

Their 186-page report was posted late yesterday afternoon, two days before the state Fish and  Wildlife Commission will be briefed on wolves, wolf management and the future thereof by WDFW Wolf Policy Lead Donny Martorello.

It’s important because buried in the aforementioned wolf plan is a section addressing the species’ impacts on ungulates.

If “at-risk” big game herds such as woodland caribou are found to fall 25 percent below population benchmarks for two straight years or others see their harvests decline by a quarter compared to the 10-year average for two consecutive seasons, it could trigger consideration of reducing local wolf numbers if that particular recovery zone has four or more breeding pairs, regardless of statewide delisting.

As for the assessment of the rest of Washington’s moose, as well as its wapiti, deer and bighorn sheep, the report looks at each species, breaking them down by major herds or zones, details recent hunter harvest, and discusses other sources of mortality and factors that may influence population dynamics, before wrapping up with “Sub-herd Concerns” and “Management Conclusions.”

“Using the data at our disposal, none of the ungulate populations in this assessment appear to show clear signs of being limited by predation,” state Hoenes, Hansen, Harris, and Nelson in the executive summary.

That conclusion may not go over well with some Evergreen State hunters concerned about what their and others’ observations are telling them about how the animals are doing in the woods.

And it’s not to say that bucks and bulls, does and cows, calves and fawns aren’t affected in other ways by mountain lions, bruins, coyotes and wolves. They are, of course.

New research is beginning to show how wolf packs affect mule deer and whitetail behavior in North-central Washington, leading to different use of habitat than before.

The authors also acknowledge that limitations in the data sets “might preclude the ability to detect impacts of predation on a specific ungulate population.”

But the assessment is another way WDFW is attempting to show hunters it is keeping its eye on wolf impacts as numbers of the wild dogs near recovery goals and the conversation begins to turn to post-statewide delisting management.

Biologists will also take to the air and woods again soon for year two of a half-decade-long predator-prey study in the Okanogan, and Huckleberry and Selkirk Ranges.

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