Tough weather hinders 2017 moose survey
By Richard P. Smith
Marquette, Mich. — Hunters and members of the Natural Resources Commission will have to wait until at least June to find out if the moose population on the Upper Peninsula mainland increased enough since the last survey in 2015 for the DNR to recommend a hunt in the future. Based on recommendations from the Moose Advisory Council established a number of years ago, the mainland moose population must achieve a minimum growth rate of 3 percent for a hunt to be possible.
The prospects for a U.P. moose hunt in the near future are complicated by the facts that estimates from the 2015 survey showed the population declined since 2013 and the DNR was not able to complete all of its normal survey flights during 2017 due to a warm spell in January when those flights are normally conducted. The DNR held a media briefing at the Marquette office on April 4 to provide the latest information about the most recent moose survey. Aerial moose surveys are conducted on odd-numbered years, alternating with elk surveys done in the northern Lower Peninsula.
“Winter weather conditions preventing some survey flights did not allow us to complete the winter 2016-17 moose survey,” DNR wildlife research biologist Dean Beyer said. “This precludes us from estimating moose abundance throughout the entirety of the western U.P. moose range. However, we will be able to generate an estimate for the core range, which in the past, has supported 80 to 90 percent of the population.”
Beyer added that most of the moose on the U.P. mainland occupy 1,400 square miles surrounding release sites where moose were transplanted from Ontario’s Algonquin Provincial Park during 1985 and 1987. The primary moose range includes western Marquette County, Baraga County and northern Iron County. He explained that the core area is about 700 square miles that’s roughly in the center of the primary range.
“The core area is divided into 29 survey plots that are two miles wide by 12 miles long,” Beyer said. “We fly the survey plots in the core area first and we got all of those done before the weather soured on us. We try to cover 50 percent (15) of the survey plots in the low density areas that are randomly selected. We only managed to complete 10 survey plots in the low density areas and they were all on the south end of the low density area. We had to abandon those to avoid geographic bias in our estimate.”
DNR wildlife technician Brad Johnson from the Baraga office coordinates the moose survey flights when they are held.
“We have three airplanes that participate in the moose survey flights,” Johnson said. “One is based at Newberry and two are based in Houghton. Each plane has two observers. The best hours to see moose from the air are between 10 a.m. and 2 p.m., so when the weather is suitable, we try to have the planes reach their destination by 10 a.m.
“When conditions are good, the planes can do two plots per day. Under ideal conditions, it takes nine days to do the moose survey. We obviously did not have ideal conditions this year. Conditions were good during early January, then we had a thaw and lost sightability when the snow melted.”
A uniform blanket of snow on the ground is important in order for observers to see moose from the air, according to both Johnson and Beyer. Even when there’s snow on the ground, observers in airplanes can miss seeing some moose because of thick habitat, lighting, obstructions and positioning of the aircraft. Beyer said that radio collared moose were used on two different occasions to determine the number of moose that are missed during aerial surveys that is referred to as a sightability index.
“On both occasions, we saw roughly 40 percent of the moose that were present,” Beyer commented. “The first time we did it, we saw 39 percent of the moose that were present and the second time we saw 41 percent. That sightability index is used in a formula to estimate how many moose are present.
“From 1997 to 2007, the western U.P. moose population was growing an average of 10 percent per year. From 2009 through 2013, that rate of growth slowed to 2 percent. The population estimate was 451 in 2013. Then in 2015 the estimate dropped to 323. However, the confidence limits of the estimates from 2013 and 2015 overlap, so we could not say with statistical confidence that the population decreased.”
A total of 187 moose were observed from the air during 2015 survey flights. The number of calves per 100 cows was down to 47 versus 57 in 2013. The number of moose seen during 2017 flights and the number of calves per 100 cows had not yet been tabulated, according to Beyer, but Johnson said he felt the number of calves seen this year was higher than in 2015.