Pheasanomics: How pheasants survive extreme winter weather.

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While not native to the Dakotas, pheasants have learned to adapt and survive most of what Mother Nature can throw at them each winter. However, pheasant mortality each winter is unavoidable as snow, ice and subzero temps have a cumulative effect on the population. Photo by Lynn Bystrom, Thinkstock.com

By Andrew Johnson

Pheasant season closed across the Dakotas in early January, but with the dawn of each new year the pheasant population faces a more formidable foe than hunters, as it must endure the often unrelenting force of a prairie winter.

The stretch of frigid temps that pinned the Dakotas down for a month from mid-December to mid-January is a prime example of the extreme weather conditions pheasants encounter each winter.

Travis Runia, senior upland biologist for the South Dakota Game, Fish and Parks Department, said pheasants can generally handle brief bouts of subzero temps.

“Surprisingly, most of our pheasants and native game birds, such as sharptail grouse and prairie chickens, can survive freezing temperatures pretty well as long as they have some high-quality habitat around,” he said. “The actual temp isn’t necessarily a killer. What is a killer is the loss of a food source when it’s covered by snow and ice.”

As temperatures drop, the laws of nature dictate that pheasants and other wildlife must use more energy to stay warm. In order to accomplish this, they must dramatically increase their food consumption.

“It becomes much more challenging for the birds if the waste grain in agricultural fields is buried,” Runia said. “Pheasants really rely on that grain, and digging and scratching for food costs them a lot of energy.”

Runia said pheasants have been preparing for winter weather since fall, storing up energy in the form of fat reserves for critical situations when they must go for a day or two without food. A healthy pheasant pheasant can easily go three days without feeding, he said.

“If they don’t eat for a few days, the first step is burning fat reserves, and almost all the birds have fat reserves,” he said. “They’ve done studies on captive birds and found they can live up to two weeks in January without feeding by relying on fat, but then they start to burn muscle tissue.”

However, captive birds aren’t spending precious energy by evading predators, seeking out suitable roosting cover or searching for food. Still, Runia said that going a few days without food isn’t a big deal for wild birds.

“It turns into a big deal when food is covered for two months at a time, though,” he said. “That’s when things start to go downhill in a hurry.”

In a six-part report on pheasant ecology he wrote for the South Dakota Conservation Digest, Runia broke down the process of how a wild bird moves from burning fat to using muscle tissue in rare cases to stay warm enough to survive.

“During years with multiple winter storms that prevent feeding for many days, fat reserves, which can make up 13 percent of a pheasant’s weight in early January, can be quickly utilized,” Runia wrote. “When fat reserves are exhausted and a pheasant cannot find enough food to generate body heat, the bird has no choice but to catabolize its own muscle tissue to generate heat.”

Even with the recent weather, Runia said this winter is nowhere near those extremes in most parts of South Dakota. However, he said North Dakota hasn’t been so lucky.

“We’re in much better shape than North Dakota right now,” he said, referring to reports of localized reports of dead pheasants as the result of the blizzard and heavy snow conditions suffered over the holidays.

Runia also said in early January that he had seen a fair number of reports of pheasant mortality due to winter weather conditions in the northcentral part of South Dakota. Snow and ice storms not only covered up waste grains left in agricultural fields, but also reduced the amount of available thermal habitat pheasants need to survive the elements.

“Blizzards like that can have a negative impact, especially if there is already snow and ice on the ground like we had up in that region,” he said. “If the cover already has an accumulation of snow, anything more inundates that habitat and the birds have nowhere to go. That’s when they can freeze to death.”

In addition to freezing to death, the lack of suitable cover can also contribute to pheasant mortality when an ice storm hits. Runia said there are times when pheasants can suffocate due to ice accumulating on the birds’ head and nostrils.

While nobody wants to see weather have a dramatic impact on the state’s pheasant population, Runia said it’s important to remember that pheasants don’t have a good batting average when it comes to their annual survival rate. Hunters, predation, weather, habitat conditions and more combine to knock out half of the population from one season to the next.

“If we look at pheasants, the annual survival rate of that bird is only about 50 percent,” he said.

The past few winters have been somewhat mild by local standards, and Runia said the current snowpack across most of the state’s pheasant range is far less than more devastating winters, like the winter of 2010-11. Following that winter, data from the GFP’s annual pheasant brood survey indicated that the pheasants per mile index fell from 6.4 in 2010 to 3.6 in 2011, a decrease of nearly 45 percent.

“On top of those bad winters we ended up having some bad springs and drought in 2012 and 2013 when the pheasant numbers really took a hit,” he said.

In 2016, the South Dakota statewide pheasant index dropped to 3.1 pheasants per mile, which is a decrease of 20 percent from 2015 and 41 percent below the index’s 10-year average. With pheasant numbers already at a critical stage, it’s likely hunters will be keeping an eye on the weather in hopes it eases up a bit, but with two months of winter left to go, the birds have a long road ahead.

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