Published February 10, 2013, 07:16 AM

Northland Nature: Squirrels resort to early meals of maple tree bark

According to the calendar, we have passed midway in our trip through winter. The actual weather during the next coming weeks will often show that winter is still with us.

According to the calendar, we have passed midway in our trip through winter. The actual weather during the next coming weeks will often show that winter is still with us.

But longer days tell us of the changing trend. We recently went beyond ten hours of daylight and as we move through the rest of the month, the days continue to rapidly get longer. Temperatures are a little slower to respond, but we may have moved past the extreme cold. Chilly nights are often followed a few days later by mild temperatures.

It is interesting to see how our local wildlife handles these happenings at this time. I have noticed lots of canine tracks, especially coyotes, as they go through their breeding period. Along the trails, their footprints mix with spots of scent markings. The cottontail rabbits that occupy the yard and the snowshoe hares of the woods also show much more activity. Their courtship and pre-mating behavior may be going on during many of these nights as they also prepare for an early birthing time.

The squirrels move in the trees in pursuit of each other. These small mammals will be having their young next month. A litter so early usually guarantees time for another litter, or two, later. With the birds, I have been hearing differing calls and sounds from chickadees, nuthatches, woodpeckers and owls as we move into late winter. Ravens fly and call in pairs. And crows, some of them migrants, are vocal now too.

We can look forward to more of this behavior in the coming weeks. But along with all this activity preceding the mating season and the impending longer warmer days, the second half of winter also can be a hard time for survival for the local wildlife.

Snow depth and temperatures will impact the wild ones, but so will the conditions of last summer and fall. If we had an ample crop of berries, fruits and nuts last year, there would be food for the whole winter. If not, some critters will get hungry and may need to change their diet to make it through the cold times.

This came to mind as I walked through the woods last week. The snow depth of a few inches allowed me to go nearly anywhere without the use of snowshoes. As always, there’s more to see here every day and today was no exception.

Up on a hillside, I found several small trees that had their bark stripped. Finding bark eaten from trees happens every winter and a few of the local residents rely on it for food. Snowshoe hare feed on the branches near the ground. Porcupines will often feed on upper branches and they tend to go for larger trees.

This situation was neither. A check for evidence on the snowpack showed the hopping tracks of gray squirrels. A dugout cache or two also confirmed this notion. Gray squirrels were chewing the bark of these small trees. Looking at the twigs told me that all the chosen trees were sugar maples. Why was this happening?

Not everything done by our local wildlife is revealed to us, but we can come up with some insights as to what is going on. The acorn crop in this woods was limited in the fall. Hazelnuts were plentiful and being tasteful, perhaps were eaten immediately and fewer stored. Other trees, except for some crab apples, were also less than normal.

It appears that the squirrels were not able to cache as much food as needed and so now, in February, they resort to another feeding source. A few weeks from now, buds will serve as food.

Gnawing animals like rabbits, hare, mice, beaver and porcupines all chew on the outer bark of woody plants, but it is the inner bark, the living layer, that gives sustenance. That is why they do not go for dead trees. These squirrels were doing the same. They went through the outer bark to feed on the green bark below. They did not need to gnaw through the whole branch. Maples are plentiful and perhaps just taste better. I had seen this type of squirrel behavior before, but usually in March when some sap was running.

We still have weeks of winter to go and along with some other wildlife, these squirrels are hungry. But thanks to the maple bark, they should survive through the coming weeks.

Retired teacher Larry Weber is the author of several books, including “Butterflies of the North Woods,” “Spiders of the North Woods” and “Webwood.” Contact him c/o budgeteer@duluthbudgeteer.com.

Tags: