NORTHLAND NATURE: An encounter with a butterfly in January
Though December of 2014 was mild and gave us a temperature of about seven degrees above normal, it ended with four days that were below the usual. The new January continued this trend for nearly two weeks. During the 17 days from Dec. 28 until Jan. 13, we recorded an average temperature of only slightly above zero degrees. Nearly every one of these days had a reading of below zero sometime during the day. And so, when the temperatures started to rise at mid-month, we accepted this respite from the chill. The phenomenon of the “January thaw” was with us again. It seems like a January thaw is a contradiction of terms, but it happens virtually every January when we will get temperatures in or above 30 degrees; some years it lastS several days, others only one day. Even during January of 2014 with its polar vortex and readings far below normal, we still experienced three days of 30 degrees or above; highest: 34 degrees. We are not the only winter residents who notice this change in the temperatures and during these mild gaps in January, we can often see critters that we don’t expect to be active now.
I was out on a nearby ski trail on Jan. 15, the day when we reached 34 degrees. As I skied, I noticed the usual trailside tracks of squirrel, deer, fox, coyote, mice, shrews and weasels, but here too was a bit of a surprise. A walker moved by dragging its tail. Being near a swamp as I was, I quickly recognized this trail as that of a muskrat. These aquatic rodents have a pretty tough winter; moving through the water, under the ice, to locate root meals. Their nearly hairless tails can freeze in the snow on most winter days, but in the conditions of this day, it moved about at will. Any muskrat out in winter is likely to suffer if not finding another water access soon. Seeing these tracks made me think that maybe a couple of other mammals, sleeping in the chill, may be out now too. And I was not surprised to find tracks of both raccoon and skunk the next day.
The January thaw had other impacts as well. In mild weather, some feeder birds do not need these handouts and get food on their own. Out on the snow, I saw two winter crane flies; one with and one without wings. But the biggest surprise of a January insect came from one seen indoors.
This week, I received an email that told of a sighting of a butterfly flitting about in a home on a chilly January day; not what we expect to see. Thanks to a few photos, I was able to identify this unexpected insect as a butterfly known as a cabbage white. (Since they are alien butterflies, they are frequently called European white or European cabbage.) The white part of the name is obvious from the colors of all four wings. The reference to cabbage may be a bit harder to tell. The butterfly is called cabbage since the larva (caterpillar) will feed on plants that are members of the cabbage family: mustards, broccoli, brussel sprouts, kale, cauliflower, radishes and, of course, cabbages. This common butterfly is often seen in our yards during warm days. They do well in the Northland and it is not unusual that they have three broods each year. This white butterfly with a wingspan of nearly two inches can be in our yards and gardens anytime from May to September. The last brood will lay eggs that hatch into a caterpillar that feeds in fall and then forms a chrysalis (cocoon) for the winter. The warming days of the following May allow for the chrysalis to open. Though several species of butterflies do hibernate through the winter as adults, this species is not one.
Apparently, what happened to this butterfly of January was that it formed a chrysalis back in the fall on a plant that was collected and brought indoors for the winter. This could happen on a flower pot, a garden tray or maybe late-season garden plants. After being exposed to the cold for a while and then brought in, the butterfly felt as though spring had come and it emerged from the chrysalis and took wing; surprising everyone in the house.
In a similar manner, a year ago, I was told of a mosquito that showed up in the home of a neighbor on a January day; a month that we expect to be free from mosquitoes. What happened in that case was the mosquito was of a species that hibernated under bark (most mosquitoes do not). The wood chosen was a piece of firewood that was brought into the warm house and the sleeper got an early awakening. Butterflies are more loved than mosquitoes and we may try to keep it alive. With very limited food sources, it is not likely to live long. But seeing a butterfly is a great sight in these dark and cold days of a mid-winter month.
Retired teacher Larry Weber of Carlton is the author of several books, including “Butterflies of the North Woods,” “Spiders of the North Woods” and “Webwood.” You may contact him at firstname.lastname@example.org.