Maine’s moose continue to be killed in large numbers by ticks. The most recent research, completed this past winter and spring, has not been released officially yet, but Judy Camuso, Wildlife Division Director, shared the following information with James Cote and me when we taped a Wildfire TV show with her on Monday.
Moose calves continue to be most susceptible to ticks. Of the 71 calves collared this past winter, 43 (61%) died.
This past winter marked the third winter season of Maine’s radio moose study. For three years, the department has monitored GPS-Collard moose cows and calves in northern Somerset County (WMD 8), and this year, the department expanded its research with a new study area in northern Aroostook County (WMD 2).
Overall, there were 149 GPS-collard moose in the two study areas. These units represent a range of environmental conditions (temperatures, snowfall, green-up) that may affect the annual survival of moose. We now have three years of data in our Somerset study area and one year in our Aroostook study area. This is a long-term study to last at least five years.
Moose mortality rates vary throughout their range in the United States and Canada. In areas with predators such as bears, coyotes and/or wolves, mortality rates for calves are as high as 80%. In areas without predators, mortality rates are generally in the 30-50% range. Recently, states such as Minnesota and New Hampshire have experienced mortality rates of 60% (MN) and 55% (NH).
Overall, of the 149 moose that were collared in the state this past winter, 71 were calves and 78 were adults. Over the course of the winter, 51 total moose died, or a 34% mortality rate. Of the 78 adults, 10% died (8 adults). Out of the 71 calves that were collared, 61% of them died this past winter (43).
Field necropsies were performed within 48 hours on all moose mortalities. Weights were taken, tick loads were counted, and tissue samples collected for later analysis in the lab. All moose had some level of lung pathology attributed to infestation of adult lungworms (Dictyocaulus spp.) and/or Echinococcus cysts. Among the calves that died, on average, these calves weighed 413 pounds at capture and had lost 100 pounds by the time of death.
Looking more closely at the individual study areas, WMD 8 had 26 calf mortalities and 2 adult mortalities. In the northern unit, there were 17 calf mortalities and 6 adult mortalities.
As in the previous two winters, the majority of the mortalities came during the period of late March into early May.
Conclusion (mine, not Judy’s!)
Last year, Governor Paul LePage vetoed a bill to expand the state’s study of the impact of winter ticks on moose, saying he thought studies were a waste of time. Given that the Department of Inland Fisheries and Wildlife wanted and needed to expand their study, the veto was very discouraging.
But the department found a way to expand the study without the governor’s support, using federal funding. Previous studies showed alarmingly high death rates. In 2014, 22 or 30 collared moose calves died, and in 2015, 21 of 35. Not good!
DIF&W’s moose biologist, Lee Kantar, told the legislature’s Inland Fisheries and Wildlife Committee in March of 2015, ““If we just took the (dead moose) results of last year, we would have concerns. And we do have concerns, but it’s going to take some time” to figure this out.
Lee’s concerns spread last year to cow productivity. He told me that Maine’s moose cows are having far fewer calves lately than they used to. And he doesn’t know why. But Judy did tell us that were seeing more cows this summer with twin calves, a good sign.
If and when Lee offers his insights into the most recent research, I will share it with you.