Higher than usual mortality rate hits state's elk calves
By Paul A. Smith of the Journal Sentinel
Posted: July 18, 2009
Hayward — Optimism for growth this year in the Wisconsin elk herd has been tempered with the loss of three pregnant cows to wolf predation and half of the 2009 year class of calves to various causes.
According to Laine Stowell, elk biologist with the Department of Natural Resources, 19 of the 39 calves born this spring have died.
"That's a high number for so early," said Stowell. "Normally we see 50 percent mortality over an entire year, not in two months."
Stowell and his crew were able to radio-collar 20 of the calves shortly after birth in May and June. Ten of those have been found dead - four due to predation by bears, two to wolves and one to an accident (found trapped under a deadfall). The cause or causes of the other three deaths remain unconfirmed.
Last year, in a late, cool spring that provided poor conditions for deer and elk across the North Woods, 38 calves were born; half are still alive.
This year featured a normal green-up, and wildlife officials were hopeful for a larger year-class of elk.
But in May, wolves in the Ghost Lake pack killed three pregnant elk, according to Stowell.
"This was a new behavior," said Stowell.
Cow-calf groups are typically less vulnerable to wolf attack. Wolves tend to prey on solitary elk, such as yearling bulls or animals that are sick or have become separated from the herd for other reasons.
The Wisconsin elk herd, found mainly near Clam Lake, numbered 150 as of July 15, about the same size as last year.
It is found at about two elk per square mile in its core range.
The state's population of wolves has increased about 14% in the last year, to a range of 626 to 662, according to DNR figures.
And the bear population - historically the predator that takes most elk calves in Wisconsin - remains very large, at an estimated 26,000 to 40,000.
DNR crews will continue to monitor the herd, including radio-tracking of individuals, through the summer.
Given the recent trend in the population, the prospect of a limited, bulls-only elk hunt in Wisconsin - planned when the herd reached 200 - is likely years away.
