7 April 2014 (NPR) JUDY WOODRUFF: In northern New England researchers are increasingly worried about what’s happening to one of the region’s iconic animals, the moose. Their numbers are significantly declining, and investigators are trying to find out whether warmer winters in recent years may be a big part of the problem. Hari Sreenivasan reports from New Hampshire. And a warning: The story contains some graphic images. MAN: Well, we get to the tower, we got to check on those two calves we’re getting funny signals on. HARI SREENIVASAN: Scientists are bundling up and prowling the forest in pursuit of the wildest large animal in New Hampshire, the moose. Their into-the-woods exploration by both foot and air is part of a massive research effort to understand why America’s iconic wild moose are dying at alarming rates. The first weeks after a long winner are a critical time for moose. And here in New Hampshire, wildlife biologists from the state fish and game department want to find out why, in the last three years, moose populations are down as much as 40 percent in some regions. Kristine Rines of the moose project with New Hampshire Game and Fish Department. KRISTINE RINES, New Hampshire Fish and Game Department: April is the month of death, when most of these animals seem to just — they are completely depleted and they just start dying. HARI SREENIVASAN: According to Eric Orff, New Hampshire field biologist for the National Wildlife Federation, the deaths have been dramatic all along North America’s southern moose range. ERIC ORFF, National Wildlife Federation: When you look at a precipitous decline in the last decade, you know, the needle is headed in the wrong direction, you know, all across the southern edge of the range, from Nova Scotia, New Brunswick, Minnesota, Michigan, all across the southern fringe of their range, moose numbers are in a significant decline.

Researchers comb the fur of a dead New Hampshire moose calf to reveal the winter tick infestation that killed it. A massive moose die-off is caused primarily by a devastating parasite, the winter tick, which survives the increasingly warm winters. Photo: NPR

HARI SREENIVASAN: To better understand what’s behind the decline, New Hampshire and Maine have hired capture teams, whose job it is to track down the moose and collar them with a radio transmitter. […] Pete Pekins, professor of wildlife ecology at the University of New Hampshire, is overseeing the project. […] The main theory New Hampshire researchers are pursuing is that the massive moose die-off is caused primarily by a devastating parasite, the winter tick. On the day we visited, biologists retrieved a dead calf that was completely covered with winter ticks. PETER PEKINS: Literally, this is the walking dead. The animal is totally emaciated. And there is no way it can survive. These are the engorged adult ticks. HARI SREENIVASAN: It is suspected the ticks latch on in fall and live off the animal’s blood for months. PETER PEKINS: They are literally being sucked dry of blood. So, they can’t consume protein to replace the blood loss. Their only choice is to catabolize their own tissues. And that is going to be their muscles. The hind legs on a moose are some the most powerful legs in North America. And that animal doesn’t have any. And it’s because it has chewed up its own body to survive as long as it can. And you can see that that is quite a bit of blood. HARI SREENIVASAN: The winter tick parasite is not new, but its explosive population growth is. Reaching an animal like this calf soon after death allows scientists to document just how many ticks there were before they drop off in pursuit of a live host. Scientists suspect that warmer winter temperatures are leading to the increased number of parasites. PETER PEKINS: Shorter winters, both on the spring and fall end, play to the advantage of the tick. [more]

Researchers track New Hampshire moose in hopes of pinpointing cause of population decline