Critters dip into savings

Northwoods Notebook

(Betsy Bloom/Daily News photos) A muskrat pauses on the ice before diving into Six Mile Creek. Muskrats are among the animals that remain active during the winter in part by caching food, building up a supply they can tap into when other sources become scarce.

This has been a relatively mild winter, one that should not have provided much of a challenge for most of the animals that endure the cold weather for the season.

March 1 was the start of the meteorological spring. Early Sunday morning will see the region shift back to daylight savings time, when we’ll switch to a sunset that doesn’t arrive until almost 7 p.m. It makes the day seem much longer, even if it isn’t.

But more perceived daylight does not a spring make. Depending on the conditions, March also can be one of the toughest times of winter for wildlife. If cold and snow persist, the creatures that try to outlast winter relying on available forage may find late winter and early spring pickings scant and the reserve fat built up last fall dwindling.

By March, much of the fruit, seed or other natural food sources have been consumed. The winter birds that favor crabapples, chokecherries and other berries — Bohemian waxwings, pine grosbeaks, American robins — appeared early this winter but have long since departed after stripping most of the trees of their bounty.

Which is why many species that endure the conditions of a northwoods winter share the habit of stashing away a supply of edibles to see them through the lean times.

A red squirrel buries a peanut.

The most easily visible practitioners of “caching” are several backyard bird species and some members of the squirrel family.

Jays, chickadees, nuthatches and crows all are known to collect and tuck away extra seeds and other food to be available later in the winter, according to an April 2016 article by Shailee Shah, “Where Is That Bird Going With That Seed? It’s Caching Food for Later,” on the Cornell Lab of Ornithology’s All About Birds’ website, www.allaboutbirds.org.

Some, like the jays, have developed a “distensible” esophagus that can expand, allowing it to carry multiple food items at the same time, the article states. Crows have a special pouch in their mouth.

The jays tend to bury food, while the chickadees and nuthatches favor tucking seeds into bark or tree crevices. They’ll use multiple sites, too, so they don’t lose all of their supply if it’s discovered and plundered.

“Most common North American feeder birds can have anywhere from hundreds to thousands of separate caches scattered around their home ranges,” the article states. Yet somehow they remember.

“Many caching species have keen spatial memory, and can remember precise locations using visual cues like distance and direction from landmarks such as rocks and vegetation,” Shah wrote. “In fact, birds such as black-capped chickadees increase the size of the brain (in the area associated with memory) as caching ramps up in the fall.”

Canada jays, which also can be found in the Upper Peninsula, have a sticky saliva they use to glue cached food in trees for the winter. It allows them to not just remain farther north than most jays in winter, but actually nest in late winter, counting on what they collected to feed their young. Which experts say likely is why Canada jays are struggling in some parts of the southern edge of its normal range — warmer temperatures may be spoiling their food stores.

Among mammals, gray and red squirrels both cache food, but with different techniques — the grays do “scatterhoarding,” burying food in a variety of sites, while red squirrels build up a single larder of mostly conifer cones in a “midden.” If our numerous backyard red squirrels are any indication, they’re more than willing to “squirrel away” peanuts in the shell to their larders as well.

Chipmunks, another squirrel family member, are a prime example of playing both sides of the winter survival strategy. They spend much of the late summer and fall weeks filling their cheeks with seeds to tote to their underground burrows. But they also hibernate to reduce their energy demands. So why the need to be so busy loading up the pantry? Well, chipmunks rouse repeatedly from their winter naps, to pass waste — and feed, though several online sources indicated they usually hoard more food than they need for these hibernation “snack” sessions.

Beavers build a large, domed lodge to spend the winter, using tree limbs, smaller branches and mud. They also collect limbs from felled trees that are stored in an underwater food cache assembled close to the lodge, to be easily reached during the winter.

Muskrats, too, build up a stash in fall for winter consumption — usually visible in muskrat “push ups,” loose mounds that not only store vegetation but can keep openings in the ice that provide access to other potential food sources.

Not surprisingly, predators don’t cache as much, considering meat can be more prone to spoilage with the fluctuations in temperatures. But weasels will stockpile dead mice and other prey when available. “Dens have been found with dozens of mice and voles stashed away, which in colder climates can last for several days or more,” the Northeast Temperate Network, part of the National Park Service, stated in a monthly Species Spotlight on the short-tailed weasel, or ermine, in August 2021.

The article adds that is why weasels that get into chicken coops may kill far more birds than it can eat. “Though it may appear to us to be a gluttonous wanton act of destruction, to the weasel’s mind it is merely stocking the larder for leaner times.”

To pursue its prey into burrows and other small spaces, weasels must remain slim, with very little body fat.

“While the weasel’s shape contributes to its hunting prowess, it also causes the animal to lose heat more quickly than a more rotund creature. To compensate, the ermine has a high metabolic rate and must eat one-third to one-half of its body weight a day, making it perpetually hungry. For this reason, ermines are active even in the coldest weather, especially at night,” according to a February 2020 Adirondack Almanac article, www.adirondackalmanack.com.

So for a creature that relies so heavily on having regular meals, it makes sense to store extra food when possible.

Fox, coyotes and wolves may cache food as well when prey is abundant or an opportunity arises, burying it underground in summer or in the snow in winter, wildlife experts say.

Betsy Bloom can be reached at 906-774-2772, ext. 240, or bbloom@ironmountaindailynews.com.


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