Tough Winter for Fawns

April 10, 2006

A study of 10 game management units' areas across southern Idaho shows that mule deer fawns are having a tough winter.

About half of last summer's fawns included in the study had died as of the end of March-most of them from malnutrition.

"It's just been a long winter," said Mike Scott, McCall Subregion biologist. Snow started falling in October, and it's been going on since then. Last June's fawns headed into the winter in pretty good shape, but they have to survive the long winter on reserves. Deer winter range provides little additional nutrition.

Winter is nearly over in most areas, but in some places those fawns still face considerable snow on the ground.

"They're losing ground all the time," Scott said. The fawns that are dying now would have been next fall's yearling bucks. But it's too early to say what effect that might have on fall hunting seasons.

Fawn mortality numbers in game management units 21A, 32, 33, 36B, 39, 54, 67, 69, 72 and 76, show an average mortality of 50 percent. The worst was unit 33 with 87 percent mortality and the best survival was unit 76 with only 16 percent mortality.

The fawn mortality study is part of Fish and Game's Mule Deer Management Program and was modified this year to meet goals of the Mule Deer Initiative, a program established to improve mule deer numbers and habitat. Biologists captured and radio-collared 241 fawns in 10 game management units across southern Idaho to study fawn mortality over the 2005-2006 winter; 121 of them died as of March 24.

A similar study in 2004-2005 showed the fawns fared much better. Of 240 fawns that year, 54 died for 23 percent mortality.

Mule deer fawn mortality results are available here.