Minnesota's intense drought has a different impact for different critters

Within a few weeks, northern Minnesota black bears preparing for hibernation will scrounge for 12,000 calories a day worth of food, a search that might lead the ravenous bruins to trash cans and bird feeders, due to a shortage of berries and nuts caused by the state's ongoing drought.

In southern Minnesota, meanwhile, ring-necked pheasants just ended what might have been their best hatch in decades, thanks to the same extremely dry conditions. The birds could benefit further by a banner grasshopper crop — the bane of many farmers — that is just now showing up on the state's farmlands, again due to the drought.

The two cases underscore that while the "severe drought'' that grips much of Minnesota, according to the U.S. Agriculture Department, affects nearly every critter — and plant — that lives here, not all suffer equally, and some actually benefit.

"Wild rice, for example, should have a banner year,'' said Mark Spoden, Department of Natural Resources (DNR) wildlife manager in Grand Rapids. "The low water really benefits the crop.''

But some lakes are so low that launching boats has become difficult.

"One Aitkin County lake I fished a couple years ago I could step level from the dock into my boat,'' said Dave McCormack, DNR northeast region acting fisheries manager. "When I fished the same lake recently, I stepped down two feet.''

Rain and cooler weather that washed over Minnesota this week granted the state a reprieve from the recent unrelenting heat (the dozen 90-degree days Minnesota experienced last month was topped in only three other Junes since 1872).

But heat and sun are forecast to return next week, with some Twin Cities temperatures again expected to reach 90.

"Farmers are concerned about rain for their crops, and everyone worries about forest fires,'' said Carrol Henderson, retired DNR nongame wildlife supervisor. "But everything that lives in Minnesota or that passes through the state is to some degree affected by the lack of rain and the heat.''

Here's a look at how different critters are faring this summer.

Deer, moose, elk: Deer should handle the heat and dry weather well, said DNR big game program leader Barb Keller. It's possible farmers might become less tolerant of deer foraging in their struggling corn and soybeans, Keller said, resulting in an increase of DNR depredation permits being issued. But the issue shouldn't be widespread.

Deer, moose — and people — meanwhile might benefit if tick survival is reduced during the drought. A reduction in Lyme disease cases in people has been correlated in some studies to drought. Similarly, moose, which can be killed by tick infestations as high as 30,000 per animal, often catch a break in dry years, when tick survival suffers. Elk, meanwhile, might, like deer, feed disproportionately on farmers' crops. But the state Agriculture Department has a fund to reimburse farmers for losses.

Ducks, geese: Ducks, which can live 20 years or more, have developed drought survival behaviors in which hens postpone nesting for a year or, if necessary, longer.

The Minnesota DNR didn't conduct a spring breeding survey this year because of COVID, so it's unknown how many birds returned to the state in March and April. Wisconsin and Michigan surveyed their spring ducks, however, and both found reasonably good numbers. Whether Minnesota also experienced a solid return of breeding ducks is unknown, said waterfowl specialist Steve Cordts, who added the state's duck picture is clouded by extremely dry conditions in the Dakotas.

"The lack of water in the Dakotas might mean more migrating ducks will come through Minnesota, because we at least have larger bodies of water, whereas the Dakotas hardly have any water,'' Cordts said. "We just don't know.''

Geese are bigger, stronger and meaner than ducks, and they occupy larger bodies of water. So they are less vulnerable to predation. Adverse weather conditions also can cause them to postpone nesting a year, in which case they might join juvenile birds on "molt migrations'' to remote northern locations.

Insects: These are the holy grail of bird life. Pheasant chicks, for example, won't last long without insects to eat, said DNR farmland and wildlife populations and research group leader Nicole Davros of Madelia.

One study, in fact, showed that pheasant chicks eat insects almost exclusively during the first six weeks of their lives. Which is why conservationists have long been worried about farmers' pesticide use and its effect on bugs.

Unfortunately, the same dry conditions that can increase pheasant nesting success can also reduce insect availability.

"In recent years in Minnesota, wet springs and early summers have been our big worries for pheasant nesting,'' Davros said. "The peak of our pheasant hatch was in the first and second week of June. As the drought has lingered, I've worried about insect production.''

Fish: Trout are cold water-dependent and are extremely vulnerable to warming water. But brown, brook and other trout in the state's southeast streams are fairly safe from this threat, because streams there are largely supplied by groundwater sifting upward through limestone bedrock.

North Shore streams, by contrast, are fed largely by runoff, and consequently are more vulnerable to low flows and higher water temperatures.

Cool water fish such as walleyes, northern pike and muskies can suffer in warming lake and river water, said DNR fisheries chief Brad Parsons, and each is vulnerable to post-release mortality if caught by anglers.

On the other hand, warmer springs and longer growing seasons can in some instances benefit walleyes and other fish, Parsons said.

"In some cases that combination has produced good year-classes of fish,'' he said.

dennis.anderson@startribune.com