MINNEAPOLIS — Minnesota's annual moose survey finds a continuing decline in the animal so closely identified with the state's north woods, the state Department of Natural Resources said Tuesday.

The survey counted 3,450 animals, compared with an estimated 4,350 last year and 2,760 two years ago.

The survey is in line with the downward trend in the moose population, the DNR said. Minnesota has about 60 percent fewer moose than it did in 2006.

The agency has conducted aerial moose population surveys since 1960. A spotter counts moose as a pilot flies a helicopter across 52 random plots of 13 square miles.

"Survey conditions this year were generally good across moose range, although there was much less snow compared to last year," Lou Cornicelli, the DNR's wildlife research manager, said in a news release.

Scientists aren't sure why moose are declining, but say warmer weather, parasites, disease and changing habitat are likely contributing factors.

The DNR also said mortality of collared moose fell slightly from last year, but the number of calves surviving their first year had also been low.

"This indicates the population will likely continue to decline in the foreseeable future," Cornicelli said.

The agency stopped allowing moose hunting in 2013 pending a recovery in the population.