Moose in Washington appear to be bucking the decline that's plaguing the animals across most of the lower 48 states, a Washington Fish and Wildlife Department biologist says.
Rich Harris, the agency's new special species manager hired last year, says annual aerial surveys and hunter success rates indicate moose numbers are at least holding steady while moose continue to expand their range westward in the state.
Idaho, however, is reporting declines in moose, primarily in the Panhandle and northcentral region where wolf packs have been revived.
Dave Koehler, Idaho Fish and Game Department wildlife biologist in Lewiston, said while predators are part of the problem, they may not be the most important factor. Citing moose studies in other states, he said habitat changes, parasites and warmer temperatures related to climate changes are believed to be major drivers of the decline.
"I'm not saying wolves are not having an impact on moose recruitment, but it's not as simple as saying they are the problem," he said.
The explanation could include other factors, such as infestations of parasites, changes in fire management and timber markets or the impacts of climate change.
Biologists across the northern tier of states are looking into moose declines:
--Minnesota's moose population is dropping so fast that conservation officials have suspended moose hunting indefinitely starting this year.
--Montana, where moose have been declining since the mid 1990s and moose hunting permits have been reduced, has launched a 10-year moose study on the health, reproduction rate and habitat of moose.
--Wyoming has documented serious declines of Shiras moose in the northwestern portion of the state over the past 30 years.
Idaho Panhandle herds are in obvious decline in some areas, such as the east side of Unit 1, said Jim Hayden, IFG's regional wildlife manager in Coeur d'Alene. "None except units 2 and 3 appear to be increasing anymore," he said.
Moose moved into Washington from Idaho. A 1970s survey indicated about 60 were in the northeast region, enough to allow three permits for Washington's first moose hunting season in 1977.
The moose population is in the thousands now -- Harris refused to guess at a more precise number -- and 140 permits will be offered this year. A moose permit is still a once-in-a-lifetime opportunity in Washington through the annual lottery drawing.
"Poring over our index data with the district biologists, we're not seeing anything other than continued increase thus far," Harris said. "But there's room for subtle things to be happening that we're not aware of."
Wolves, for example, could be having significant impacts in small areas, he said.
Still, hunter harvest continues to be around 135 moose a year, with success rates running 92-97 percent.
Idaho is issuing 859 moose permits statewide.
Idaho, which relies heavily on hunting success rates in monitoring its moose population, is offering 695 bull tags statewide this year, down from 814 offered in 2010. Antlerless tags have been reduced from 197 to 164 in that period.
The permits are prized; hunters have around a 15 percent chance of drawing one.
The biggest decreases in permits have been in the Clearwater Region, where 262 moose permits were offered in 2004. This season, only 98 tags are offered.
"It's been a fairly precipitous drop and it's been fairly steady over the last 10 years or so," Koehler said.
The agency doesn't have hard data on moose numbers. Instead it relies on the success of hunters and anecdotal field sightings to gauge the health of the moose herd. When hunter success rates dipped below 75 percent, the agency called for permit reductions in some areas.
"In the Panhandle, we've had emergency closures for cow moose hunting except along the Washington border, and reduced bull moose permit numbers in Hunt 1-3 and Hunt 1-4 in particular," Hayden said. "Success rates there are in the 40-50 percent range instead of the usual 85 percent or so.
"It's not all bad news," he added, noting that permits likely will increase in units 8 and 8A, where hunter success rates have been near 100 percent for more than a decade.
"Other areas we're still watching -- but data are few with moose, just not enough money to monitor outside of harvest."
Washington issued 150 once-in-a-lifetime moose hunting permits last year. Although the number will decrease to 140 in 2013, it's not a reduction in moose hunting opportunity.
The number of advanced hunter education permits -- issued to hunters who are on-call for dealing with moose that are causing damage to crops or a public hazard -- will be reduced from 20 to 10, Harris said.
"Only a few of those hunters have been used in recent years, so we're just reducing the frustration of too many hunters waiting around with permits and never getting called," he said.
Harris hopes to step up Washington moose surveys to get more detailed population trends. "We don't have an unending budget," he noted, and any increases in research will take a few years to gel into more precise estimates."
As big as they are, moose are difficult to count. Aerial surveys must be scheduled in the narrow window of winter when snow is on the ground to make them visible and before the bulls drop their antlers. Distinguishing the gender is important survey data.
"The weather at that time of year makes the flying window even smaller," Harris said.
This fall the agency will ask hunters to voluntarily bring moose heads to offices so biologists can take tissue samples to monitor for parasites.
Moose have extended their range westward, with cows raising their calves in Walla Walla and Ellensburg, Harris said. "We think their numbers are still going up, but we know that no wildlife population continues to increase forever."