Moose in northeastern Minnesota continue their population decline, the Department of Natural Resources said on Thursday.

Not only were moose numbers down from a year ago -- 5,500 to 4,900 -- but an aerial survey showed the proportion of cows accompanied by calves also fell.

"These indices, along with results from research using radio-collared moose, all indicate that the population has been declining in recent years," said Dr. Mark Lenarz, DNR forest wildlife group leader.

The DNR has recorded a downward trend of northeastern Minnesota moose dating to 2005. Along with the fallen calf-to-cow ratio, the bull-to-cow ratio also has declined, to 64 bulls per 100 cows.

Non-hunting mortality of northeastern Minnesota moose fell between 2002 and 2008 at a rate higher than in moose populations outside of Minnesota, the DNR said. Reasons for the falloff are unknown.

Of 150 adult moose fitted with radio collars since 2002 in Minnesota, 114 have died, perhaps from disease or parasites. Ten were killed by vehicles, two by trains and nine by wolves.

A moose mortality study beginning in 2012 has been recommended by the Legislative-Citizen Commission on Natural Resources, which oversees lottery funds dedicated to the environment.

Copies of the aerial survey are online at