Winter ticks took a heavy toll on young moose again this year despite hopes that a fall drought would help kill off some of the parasites.
Lee Kantar, a moose biologist with the Maine Department of Inland Fisheries and Wildlife collared moose calves had a 72% mortality rate this year because of high numbers of winter ticks.
Kantar told Maine Calling that drought conditions can dry out tick egg sacs and reduce the population before the fall, when they attach to animals.
"What happened is we had just as many winter ticks getting on moose than the previous year and we saw that in a very high mortality rate in the calves trying to make it to their first birthday," Kantar said.
Even though MDIFW only has data on the moose calves it has equipped with GPS collars, it is broadly representative of the state's population, according to Kantar.
"There may be some spots that are hot spots and some spots not bad but if you want to look at it conservatively we would say that is fairly representative," Kantar said.
A warming climate and less severe winters have increased the threat that winter ticks pose to Maine's large moose population.
Tens of thousands of ticks can attach to a single moose. The parasites only prey on a single host through their life cycle and their feeding can be deadly to young moose and reduce fertility in adult females.
Kantar said high density moose populations also encourage a higher number of winter ticks and the department is studying whether having fewer moose in a region could improve outcomes.
According to Kantar the department has been tracking calves since 2014 and the highest annual mortality it recorded was 87% while the lowest was 8%.
