Grand Rapids, Minn. — DNR Wildlife biologists say a recently
completed survey that found 6,500 moose in northeast Minn-esota is
the most accurate to date.
Until last year, the aerial survey had indicated that the moose
population was stable at approximately 4,000 moose. The boost in
moose surveyed in the past two years is the result of changes in
survey techniques, not an actual increase in the moose
“We flew the survey using helicopters rather than fixed-wing
aircraft, which gave observers more time to see moose,” said Mark
Lenarz, a DNR wildlife research biologist who coordinated the
survey. “We also used a new survey technique that was pioneered in
Idaho for estimating elk numbers in the pine forests of the
Lenarz said the new survey technique, developed for counting elk
in heavily forested areas, is well suited to the coniferous forests
of Minnesota’s northeastern moose range. Each observation of moose
is corrected based on the amount of visual obstruction where the
moose is sighted.
The correction factor used in this survey was developed using
radio-collared moose that are part of an ongoing study of moose
population dynamics in northeastern Minnesota.
“Each year we will refine this correction factor using the
radio-collared moose and improve the accuracy of our population
estimates,” Lenarz said.
The 2004 survey, which estimated 8,500 to 11,000 moose, was too
high, biologists say, due to inconsistent measurements on the
amount of visual obstruction.
Aerial surveys have been conducted each year since 1960, and are
based on flying transects in 36 randomly selected plots spread
across the Arrowhead. This year’s survey was conducted by the DNR,
the 1854 Authority, and the Fond du Lac band of Lake Superior
Mortality study continues
For the past three years, researchers have been tracking
radio-collared moose in hopes of learning why the moose population
in northeastern Minnesota isn’t increasing.
While this year’s higher survey counts are encouraging, the
study has identified nonhunting moose mortality between 21 and 24
percent in the study’s first two years.
This year’s nonhunting mortality rate in northeast Minnesota was
9 percent, Lenarz said. The non-hunting mortality rate for moose is
generally between 8 and 12 percent elsewhere in North America.