City Wilds: Surviving winter’s extremes

I suppose I started to feel sorry for myself while repeatedly shoveling wet, slushy snow from my porch, sidewalk, and parking areas and having to carefully step across slick ice to get the morning paper and maneuver my car through the awful rutted mess of the back alley. Then I got to thinking about my privileged life and the fact that I could stay at home for much of Anchorage’s mid-February meltdown.

Many people have it lots harder; the homeless, of course, but also those who don’t have their own transportation and must negotiate our city’s unwalkable sidewalks, sometimes dodging traffic while picking their way along local streets. And people who don’t have any choice but to daily drive—or at least make the attempt—to work along roads slickened by freezing rain. Those folks, and others, are the ones truly challenged by winter’s extremes here in our northern city.

Given my love for what we humans call the “natural world,” my thoughts also naturally turned to the wild creatures who every day face the vagaries of Alaska’s winter weather.

The question rose: which animals would be most harmed by warming temperatures that reached 40 degrees, the freezing rain, the repeated melt-freeze cycles that turned the local snowpack into soft slush and then hardened ice? I had my own suspicions, but also turned to those who more closely study the lives of Alaska’s wildlife. I asked two reliable local sources, Rick Sinnott and Dave Battle (the former a retired state wildlife manager, the latter currently employed by the Department of Fish and Game). And I also re-read a story by UAF Geophysical Institute science writer Ned Rozell, who in early January wrote about “How a single winter rainstorm in Interior Alaska could wreak havoc on animals and their habitats.”

Here’s some of what I learned about a few chosen animals.

In the overall picture, Sinnott notes, “The extensive freeze-thaw events that are happening in Alaska will help some species and hurt others, and any changes in one population or species will affect others in often unanticipated ways.”

It will come as no surprise that the lives of moose—which often intersect with the lives of humans in and around the Anchorage area—have been among the most compromised by our mid-February meltdown (and the earlier one in the Interior region).

The biggest hazard for moose in urban environments is ice. As Sinnott notes—and as anyone who has observed moose can readily appreciate—“Moose aren’t well adapted to ice. They are large, their legs are long and their hoofs are hard. Imagine walking on a frozen surface like a lake or marsh with wooden blocks attached to your feet. They feel rather vulnerable and they are. A moose that falls on ice can injure its pelvis and be unable to stand. It’s difficult to dodge wolves and cars on an icy surface. Icy crust on snow will shred the skin on their legs. It’s painful to walk and (yet) they must walk to eat.”

Battle too emphasizes, “Moose can slip and injure themselves on icy roads (or trails) just as easily as people can. We know of a number of times this has happened. I believe it was my predecessor, Jessy Coltrane, that once saw a moose slip on an icy road and do a ‘split’ and break its pelvis.”

In wilder, more remote areas, where moose must contend with wolves rather than vehicles, freezing rain can create thick crusts that hamper the ability of moose to escape their predators. Rozell quoted former state biologist Dick Bishop, who noted that moose suffer in such conditions because it takes a large amount of energy to move even short distances through such a snowpack. Besides that, if the icy surface is thick enough, “Wolves are able to travel on top of this crust. That’s a heck of an advantage.”

Because moose have such a hard time moving through deep snow that’s been through repeated freeze-thaw cycles, they naturally prefer firmer surfaces on which to walk, like those on roads and trails. Whether in urban or rural areas, that leads to more conflicts with people, whether in cars, on foot, or driving dog teams. As widely reported in the media, there have been numerous instances of moose charging sled dog teams this winter, resulting sometimes in both dead dogs and moose.

Bears, too, can be affected by mid-winter meltdowns, though for them it’s usually more of an inconvenience than a life-threatening event. “It wouldn’t be surprising to have some bears that are getting wet in their dens get up and wander around a bit,” notes Battle, though as of Feb. 19, “we haven’t received any reports of that yet.”

At the other end of the “wildlife spectrum,” says Sinnott, “you have tiny creatures like voles and shrews who spend most of the winter insulated from the cold and somewhat protected from predators by snow cover.”

A single, brief freezing rain event that produces an icy crust upon a still largely soft and fluffy snowpack can benefit such tiny mammals in their subnivean passageways, making it harder for predators to hear or reach them, for instance the great gray owls that have been observed hunting in local woodlands this winter.

Great grays and other owls, says Sinnott, “have super-sensitive hearing, asymmetrical ear apertures, and adjustable facial discs that act like a radar dish. Using these adaptations, they can hear and hone in on the exact location of a mouse (or vole or shrew) under the snow. Of course deep snow and an icy crust neutralize those advantages to a greater or lesser extent. So it may be the owls that suffer the most from an icy crust.”

Things change, however, with prolonged rains and thaw-freeze cycles that affect the entire snowpack. In such circumstances, Sinnott observes, the food that voles and other subnivean residents depend can become “encased in ice and their protective blanket of snow (may become) sporadic or disappears entirely in some areas. So they starve and freeze to death. To put it in terms a human can understand, what would you do if you were unable to get into your refrigerator or pantry? And you couldn’t get food anywhere else because your neighbors were highly territorial and would fight tooth and nail to keep you away.”

Farther north, when interviewed by Rozell, university ecologist Knut Keillland speculated about what might happen to subnivean creatures when a thick icy crust forms within the snowpack. “The ice is likely to slow the diffusion rate of carbon dioxide out of the snowpack. If so, everyone beneath the crust will sooner or later be in need or fresh air. How well they can chew their way through the crust remains to be seen.”

Whether it’s because they need to find oxygen or their food reserves are depleted, tiny mammals may be forced to leave their hidden tunnels and move atop the snowpack. Great grays and other owls and raptors “love it,” notes Sinnott, “when voles and shrews are forced to scurry around on top of the snow and ice.”

There are myriad other stories to tell, but you get the picture: unusual weather events can make winter survival even more difficult than usual for Alaska’s wildlife. And which species benefit or suffer may change quickly, depending on the nature of the weather events that occur. Most of us humans pay little or no attention to how the changing weather is affecting our wild neighbors, while bemoaning weather’s impacts on our comparatively easy lives.

Anchorage nature writer and wildlands/wildlife advocate Bill Sherwonit is a widely published essayist and the author of more than a dozen books, including “Living with Wildness: An Alaskan Odyssey” and “Animal Stories: Encounters with Alaska’s Wildlife.” Readers wishing to send comments or questions directly to Bill may do so at akgriz@hotmail.com