Winter Severity Index monitors health of northern deer herd

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SPOONER Wis. – State wildlife staff are again monitoring the effects of winter on the state’s northern deer herd using as system known as the Winter Severity Index – and so far things look pretty good. The index uses a combination and accumulation of cold temperatures and deep snows that historically have proven to affect the health and population of deer.

Biologists and other department staff add the number of days with daily low temperatures below zero degrees Fahrenheit (F) and the number of days with 18 inches or more of snow on the ground. Up to 50 combined points at the end of the winter is considered mild, from 51 to 80 is considered moderate, 81 and over is considered severe, and any totals over 100 points are considered very severe.

To date, most of northern Wisconsin has snow depths that allow good deer movement, according to Mike Zeckmeister, Department of Natural Resources northern region wildlife biologist.

“About half of our stations are reporting winter points over 20, the other half are 20 or less,” Zeckmeister said. “What stands out this winter is that it started early. We have had below average low temperatures, and snow depths have just hovered below the 18-inch reporting level at many stations up to the end of January.”

Zeckmeister said that with a little more snow, most stations will be adding snow days to their reporting. “Depending on what happens for the rest of the winter, we could go either way. We will factor all of this in, including the final Winter Severity, when we set deer quotas later this spring,” he said.

The north’s 2010 deer population was in good shape and hunters helped reduce deer numbers going into the winter, and this will help them survive. Last year's winter was considered mild, the biologist said, "and we saw a very early spring green-up that provided sustenance for pregnant does, insuring a healthy fawn crop."

Zeckmeister said that last summer’s ample rainfall provided good growth of summer vegetation that helped deer build up fat reserves for this winter.

“Our November deer harvest trimmed the herd in most areas and that means fewer deer having to compete for winter forage,” he said. Too many deer going into a winter can seriously degrade winter browse and cover that can take years to recover and hinder overwinter survival of deer.

Listed below are indexes (combined below zero temperatures and 18 or more inches of snow) and snow depths as reported by department staff:

Wildlife managers are currently studying deer populations and planning for the 2011 deer season. Public meetings will be held in March with citizens to discuss the condition of the deer herd and prospects for next fall’s season. Zeckmeister said that people interested in deer and proposals for next fall’s deer seasons should watch for announcements of these local meetings.

FOR MORE INFORMATION CONTACT: Michael Zeckmeister (715) 635-4090

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