Wild Georgia: Some butterflies may flit about on warm winter days

I was strolling in a DeKalb County park the other day when I was delighted to see an apparent mourning cloak butterfly flitting about. Like me, the hardy creature probably was taking advantage of a gorgeous day in early January with sunny skies and temperatures in the mid-60s.

Seeing a butterfly in the dead of winter may be surprising to some, but there’s a small group of Georgia butterflies that may venture out on warm winter days. Besides the mourning cloak, some other species include the variegated fritillary, red admiral, American lady and eastern comma butterflies.

They tend to spend winter as adults mostly hunkered down in crevices, under or in between logs or underneath loose tree bark — but occasionally coming out in suitable weather.

Generally, however, most of Georgia’s some 170 butterfly species survive winter as eggs, caterpillars or pupae. Caterpillars of the great spangled fritillary and pearl crescent species, for instance, overwinter in leaf litter or in the ground. The Eastern tiger swallowtail butterfly overwinters as a chrysalis.

Monarch butterflies, of course, migrate to warmer climes in Mexico to escape winter. Some others, such as the cloudless sulphur and gulf fritillary, also might migrate south but for much shorter distances.

It’s crucial that butterflies have winter survival strategies. Unlike mammals and birds, butterflies are cold-blooded, meaning they have no way of regulating internal body temperatures. Without some way of warding off cold, they will die.

Generally, butterflies are most active when temperatures are 80-100 degrees. Below 60 degrees or so, the insects usually stop flying because, at that point, their flight muscles won’t contract and they can’t flap their wings.

So, on freezing winter days, such as during Georgia’s severe cold snap in late December, even the hardiest of butterflies will not venture out.

IN THE SKY: From David Dundee, Tellus Science Museum astronomer: The moon will be last quarter Saturday night. Mercury is low in the east before dawn. Venus is very low in the west just after sunset. Mars is high in the east at dark. Jupiter is in the south at sunset and sets about four hours later. Saturn is very low in the southwest at dark.

Charles Seabrook can be reached at charles.seabrook@yahoo.com.