Calving season: Alaska moose population doubles in a month

However, it won't take long for bears and wolves to take advantage of the boom.

The monthlong moose calving season began almost two weeks ago. State wildlife biologists say approximately 120,000 moose calves will be born by the first week of June.

Fairbanks moose research biologist Rod Boertje said of that number only about 30,000 will survive a year. Most of the calves that perish will be killed by black bears, grizzly bears or wolves soon after they are born.

"Over 40,000 will be killed in the first six weeks," Boertje said.

According to state studies, the average mortality rate for moose calves 1 year old or less in Interior Alaska is 65 to 70 percent.

"Out of those 120,000 calves, about 80,000 are killed by predators and another 9,000 die from other causes," Boertje said.

Drowning is the most prevalent non-predatory death. Calves also die from sickness, starvation, abandonment and genetic defects.

On average, about 80 to 85 percent of adult cow moose in Alaska get pregnant each year. Because many cows have twins, the number of calves born exceeds the number of cows giving birth. Based on those numbers, biologists estimate the average annual moose calf crop in Alaska at around 120,000 calves.

Studies indicate that bears kill more moose calves than wolves do in most areas.

That's no surprise, said biologist Mark Keech, who studies moose in the McGrath area, where black bears are the predominant predator of moose calves.

"It's an opportunity, and bears are opportunists," he said. Bears, especially black bears, far outnumber wolves in most areas of the state.

The moose calf survival rate near McGrath jumped 15 percent in the five years after the Department of Fish and Game relocated more than 100 bears in 2004-05 as part of a black bear control program.

Keech said the moose calf survival rate before black bears were removed was about 30 percent. In the five years following the bear removal, the survival rate increased to about 45 percent.

"That's essentially what bears kill, calves up to two months of age," Keech said.