Hot hunting: Warm autumns have become a disruptive pattern

Minnesota's recent string of unusually warm autumns hasn't gone unnoticed:

• Deer hunters bring plenty of ice to deer camp to ensure their venison doesn't spoil.

• Pheasant hunters carry water bottles in their hunting vests to hydrate their canine partners.

• Duck hunters often bring bug dope or sunscreen to their blinds — and not as a joke.

• And dove hunters, well, some wear shorts when the season kicks off in early September.

What's going on?

It's the heat.

The warming trend has continued this fall. September was the state's warmest on record, going back to 1895. Pheasant hunters and their bird dogs weathered August-like temperatures in the 70s and 80s on opening weekend.

"We really haven't had a cold fall in a long time," said Pete Boulay, climatologist with the State Climatology Office. "There's a whole generation of hunters who don't remember cold falls."

Boulay noted that since 1970, Minnesota's daytime maximum temperatures have increased 0.6 degrees per decade.

"The trend is statistically significant," he said. "Minnesota has only had two autumns in the 21st century where the daytime temperatures have been below the long-term average."

For bikers, hikers, paddlers and other outdoor enthusiasts, the warm falls have been a blessing, extending their seasons. And, helped by the weather, this year's the fall crop harvest is ahead of schedule.

"The [Weather Service's] Climate Prediction Center has us staying on the warm side through mid-November," Boulay said. "If you're looking for snow to track deer, it might be a while."

The recommendation: Better bring ice again to deer camp.

Globally, 2015 likely will be the hottest year on record, beating a record set just last year. Officials say the immediate cause is El Niño, when the ocean releases large amounts of heat into the atmosphere. Boulay says it's uncertain how El Niño will affect Minnesota's weather this fall and winter.

"We had the driest winter on record during an El Niño, and the second-wettest winter on record, so anything could happen," he said.

A changing climate raises concerns for wildlife officials, including those at Ducks Unlimited.

And various studies project trouble for the Prairie Pothole region, which includes portions of Minnesota. Changing climate could reduce wetlands there, affecting waterfowl populations. The National Wildlife Foundation projects a 19 to 39 percent decline in ducks by 2030 in the Mississippi Flyway, which includes Minnesota.

And Minnesota officials still are trying to determine the cause of a moose population decline; the effects from warmer winters are one possibility.

So with warmer falls becoming more prevalent, might Minnesota shift hunting seasons later? Unlikely, said Ed Boggess, Department of Natural Resources (DNR) Fish and Wildlife Division director.

"The timing of most of our seasons is based more on the life cycles of species," he said. Minnesota's regular firearms deer season, for example, is timed to occur during the rut. The photoperiod — the shift to less daylight in the fall — triggers the rut, not temperatures, Boggess said.

Climate change could be affecting waterfowl migration, resulting in ducks and geese staying in Canada longer before migrating south. That obviously affects Minnesota hunters. Ironically, the trend in Minnesota has been to offer earlier waterfowl hunting opportunities, in August and September.

"If ducks are hanging up north until after our season is over, than that could prompt some interest [in a later duck season]," Boggess said. But no changes are imminent.

"Last year, we had an early freeze-up," he noted.