mild winter boost deer population

[Lee Borgersen]

 
Another mild winter for deer likely to boost population  
 
  
 
With about six weeks of winter remaining, it’s shaping up to be another mild season for the region’s white-tailed deer population.

While the past few weeks have featured colder-than-normal temperatures and frequent snow, mild conditions throughout the first half of the winter have left deer in good shape to weather the rest of the cold weather.

Barring another outbreak of exceptionally heavy snow, or another extended stretch of below zero temperatures, the region’s deer winter severity index is likely to finish up significantly milder than usual, according to Tom Rusch, the DNR’s Tower Area Wildlife Manager.

The winter severity index is determined by a combination of snow depths and cold temperatures. A point is added to the index for every day that snow depths exceed 15 inches or for every day with a below zero temperature reading.

As of Feb. 3, the index sat at 31 in Tower and most other stations in northern and central St. Louis County, and all of those points were from below zero temperatures.

Heavy snow on Feb. 10 has pushed snow depths above 15 inches, which should start pushing up the index at least one point daily for the foreseeable future.  Snow depth is a critical factor for deer survival, since deep snow can significantly limit the ability of deer to move around and access food. Limited snow also allows deer greater mobility to escape predators, while deep snow can give the advantage to wolves, said Rusch. With the deeper snow in recent days, deer have begun to yard up, something they had not so far this winter in most parts of the region.

Despite the recent snow, Rusch still expects the 2012-13 winter to wind up with a severity index of 100 or less.

“If that’s the scenario that plays out, the 2013 fawn crop would be the second consecutive bumper fawn crop in St Louis County, with back-to-back mild winters,” Rusch said.  “Consecutive large fawn crops historically have put population growth on the fast track.  Time will tell, but the prospects for the northern Minnesota deer population appear to be on the rise.  By March 1, we will have a firmer grasp on the effects of this winter on our white-tailed deer population.”