It is the time of year again when motorists need to slow down and be cautious - because deer likely won't be.

The annual rutting season has begun, the time of year when deer breed.

"The rut brings out abnormal behavior in deer and they sometimes lose their fear," said Steve Dewald, Wisconsin DNR conservation warden in the La Crosse area.

And when one deer appears, "there's probably more following," Dewald said.

"If you see a deer, don't look where that deer went. Look where that deer came from, because that's where the second one will come from," he said.

Minnesota averages 19,000 motor vehicle collisions with deer a year, causing 450 injuries and two deaths, according to the Minnesota DNR.

Mature deer aren't the only ones to watch out for during the rut, said Jim Konrad, Minnesota DNR enforcement director.

"Summer's fawns can also make their ways onto roadways after their mothers leave them to mate," Konrad said.

About 24 percent of the nearly 16,000 motor vehicle-deer collisions in Wisconsin last year happened in November, which was about average for the month, State Department of Transportation analyst Donald Lyden said.

Deer crashes peak in October and November during the breeding phase.

The state had 10 fatal crashes involving deer in 2008, with another 99 people suffering serious injuries. Motorcyclists were particularly vulnerable, accounting for seven of the fatalities in 2008.

A roadkill deer does offer one benefit - it can be claimed for meat, officials said, usually by contacting a law enforcement officer in the county.