Idaho Researchers are Possibly Pinpointing Reduction in Moose Population, Impacts on Hunting

by Jennifer Shea

University of Idaho researchers have been working with Idaho Fish and Game officials to help Idaho’s moose population rebound from recent population declines.

The two groups launched a multi-year research project earlier this year that aims to track the moose and determine what’s killing them off. So far, the project has turned up a better adult survival rate than anticipated, according to But, overall population declines are continuing.

Idaho Scientists Track Moose Deaths

The researchers put tracking collars on 112 moose. And about 89% of those adults survived the autumn. Biologists are also testing the moose for diseases, parasites and other potential problems.

“It really was a pleasant surprise,” Fish and Game wildlife research manager Mark Hurley said of the survival rate. “We expected survival to be lower than that, given that moose populations are declining throughout the southern part of their range, including in Idaho.”

The moose population is declining across the U.S., per It’s been an urgent concern since at least the early 2000s. The problem started in the northeastern U.S. but eventually spread to the Rocky Mountain states. 

Moose Declines Affect Hunting

And that has affected hunting conditions in many states. Idaho moose numbers peaked in the 2000s; moose tag numbers have dropped statewide since 2009. And the 2021-22 season may bring the largest drop in tags in 30 years.

Researchers believe the problem may lie with the moose calf population since the adult group seems to be faring relatively well. 

“It is possible some pregnancies aren’t being carried to term, or there is a significant cause of early calf mortality, and we will continue to look at that,” Fish and Game wildlife research coordinator Shane Roberts said. “While there will always be some calf mortality before we’re able to observe them the first time after birth, there is a discrepancy worth looking into further.”

Among the adults, winter ticks and parasitic diseases were the primary cause of death. Infectious diseases were the second most common cause of death.

“Those are some causes of mortality we shouldn’t be seeing in any species — tick-related deaths, or deaths related to external parasites,” Hurley said. “But we are seeing them, and they are really specific to moose.”