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Wednesday, December 11, 2019  Spokane, Washington  Est. May 19, 1883
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Sports >  Outdoors

Rich Landers: Critters are masters at enduring bitter cold

Deer usually handle cold winter weather unless factors such as deep snow restrict their daily movements to feeding areas and shelter. (RICH LANDERS richl@spokesman.com)
Deer usually handle cold winter weather unless factors such as deep snow restrict their daily movements to feeding areas and shelter. (RICH LANDERS richl@spokesman.com)

Judging from the bloom of down coats showing up downtown this week, humans have learned a few valuable lessons from wildlife about surviving bitter cold weather.

But critters are the masters at enduring cold with their own feathers, fur, fat, mobility and other adaptations beyond human capability.

Marmots and grizzly bears have taken the easy way out by fattening up before checking in to sleep in winter dens.

Meanwhile, pikas – the “rock rabbits” of mountain talus slopes – stay cozy and active under deep snow feeding on some 50 pounds of “hay” apiece stashed in rock crevasses.

The ospreys that dove into area lakes for fish to feed their young last summer are long gone. They flew the coop even sooner than some of the local “snowbirds” who are wintering in Arizona RV parks.

One of the mysteries of migration can be observed in the Swainson’s and red-tailed hawks. Both species have the same ecology – they rely on the same habitat and prey. But the Swainson’s is a long-range migrant that goes all the way to South America for winter.

The redtail toughs it out here.

Some critters move relatively short distances to survive winter. Many mule deer in Lincoln and northern Whitman counties already have migrated to the Snake River canyon, where average temperatures are a few ticks warmer. Wind and snow helps keep portions of the south-facing slopes free of snow for easier foraging.

Black-capped chickadees pull together several adaptations to get their tiny bodies through a freezing night.

Like most birds, they can fluff out their feathers, more than doubling their apparent size, to trap body warmth in the downy insulation under wind- and weather-shedding outer feathers.

Bird legs and feet are resistant to frostbite because they have little soft tissue that needs blood circulation for warmth.

“The few muscles that operate the foot are mostly higher up in the feather-covered leg and connected to the bones of the feet with long tendons,” said Bruce Auchly of the Montana Fish, Wildlife and Parks Department.

While a dusky grouse might burrow solo into snow for shelter, chickadees and some other species might cluster together.

Bird experts recommend cleaning out nest boxes in fall rather than waiting for spring to make room for several birds, up to dozens, that might hole up in a single cavity to weather a storm.

Similarly, winter-wise fans at the Eastern Washington Eagles football game this weekend will be wearing puffy air-trapping clothing under a wind-stopper layer. They’ll wear insulating hats and hoods – our heads radiate tremendous amounts of body heat – and be snuggled into the crowd of fans to share body warmth.

But unlike the fans who will go home to heated environments after the game, the chickadee has adapted to stay out in the cold. It will fuel up on food and then roost and enter a state of regulated hypothermia, plunging its body temperature to conserve energy overnight.

Birds maintain a constant body temperature by metabolizing food into fuel that keeps their blood warm as it pumps through their circulatory system.

Some birds, including the chickadee, can shiver specific muscles to increase metabolism and generate extra heat if needed.

The normal body temperature of humans is 98.6 degrees, but birds maintain higher daytime body temperatures – from approximately 103 degrees for grebes and other large birds to roughly 112 degrees for song sparrows.

Chickadees conserve fuel by dropping their nighttime body temperatures as much as 10-12 degrees. Essentially, they damper the flue to burn fuel more slowly overnight. If the birds have judged it right, coals will still be glowing in the morning, when they’ll flock to feeders and other food sources.

Deer, elk, moose and mountain goats also take advantage of the insulating qualities of trapped air.

Starting in fall, they pile on dense, heat-trapping woolly undercoats covered by long, thick guard hairs that shed the weather.

The apparel change is most obvious in late spring when they shed their winter coats a patch at at time to reveal sleek, shiny summer coats geared less to insulation and more to deterring biting insects.

Like the chickadee that puffs up its feathers, an elk can make hair stand on end to create a thicker coat that traps more body heat.

Birds and animals are more visible to humans in cold snaps because they’ll spend more time in the open absorbing solar energy and feeding to fuel their internal heaters.

Winter weather isn’t a major issue for most wildlife if they’re in good condition coming out of fall and they have food, water and habitat for shelter. Yet their existence in the wild is always a bit precarious.

Fat stores in critters, birds and mammals alike are like long-distance fuel tanks. They can’t afford to lose too much of that insulating energy during winter by fleeing cats and loose-running dogs or shed-antler hunters on winter range.

Deer and elk will survive normal winters just fine if their movements to food and shelter aren’t blocked by exceptionally deep snow.

They are most vulnerable in spring, when people have put away their down coats and begin looking for opportunities to don t-shirts and shorts. If disturbed too much in April, when they’re thin, weak and teetering on the edge of survival, deer and elk can drop like flies.

But that lesson is down the road. This week it’s colder than hell outside. If you’re not a snowbird, do your best to survive winter like a chickadee.

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