Take a walk on a warm winter day, and you're likely to make several curious observations.
Cardinals, Carolina wrens, and song sparrows may be in full song, making it sound like spring. Feeders will have much less activity because insects stir when the thermometer jumps above 40 degrees, and most birds love live food. (That's why more and more backyard birders offer mealworms all year long.)
Chipmunks wake from their winter sleep and gather more food for the inevitable return of snow cover and frigid temperatures. And if you see a few butterflies, it's not your imagination..
Several methods: Butterflies pass the winter in a variety of ways, some more conspicuous than others.
Monarchs migrate to Mexico in late summer and early fall, and new generations return in the spring. Other butterflies migrate, but their movements are usually more emigrations than true migrations. American Ladies and Buckeyes, for example, overwinter as adult butterflies, but they cannot survive cold winters. So each spring southern populations move north each spring to recolonize these areas.
Some butterflies such as the American Copper overwinter as eggs. Fritillaries, Viceroys, and Red-spotted Purples survive the winter as caterpillars. And swallowtails, whites, sulphurs, and skippers lie dormant this time of year in their pupal case or chrysalis..
But a hardy few butterflies actually overwinter as adults. They hibernate in hollow logs and tree cavities and behind loose slabs of bark on dead trees. Here their delicate wings are protected from wind , rain, and snow. Mourning Cloaks, Eastern Commas and Question Marks are members of this group.
Wasps love them: These are the butterflies that MIGHT possibly use a butterfly box as a winter refuge. But don't count on it. I've never found a butterfly in a butterfly box. But wasps love them. Each year mine are filled with nests of paper wasps. If you consider a butterfly box nothing more than a garden ornament, you're less likely to regret its cost.
A better, more natural butterfly shelter is a wood pile. You'll need a supply of logs three to five feet long. Begin with a foundation of logs, six to 12 inches apart, about as long as the logs are. This will result in a square pile. Place each succeeding layer of logs perpendicular to the previous one, and build a criss-cross stack of logs three to five feet high. By stacking the logs loosely, plenty of roosting space is provided. Cover the top with a piece of plywood or a tarp, and anchor this roof with a final layer of logs. Place the shelter in a shady spot to prevent resting butterflies from baking under the summer sun. In the winter, when trees are bare, the sun warms the shelter..
An obvious question about butterflies that emerge on warm winter days is, "What do they eat?" There are no flowers and thus no nectar available in February. But that's OK because these species prefer other sources of food.
They eat rotting fruit, animal dung, carrion, and sap. So winter butterflies love fallen apples that deer have overlooked and piles of excrement. If their tiny brains permitted it, they'd revel at roadkill.
And though sapsucker wells may madden homeowners, the sap flow that results nourishes not only the sapsuckers, but also winter butterflies. In April and May, hummingbirds join the sugary banquet..
Reasonable question: Another reasonable question about these winter butterflies is, "What's with the punctuation mark names?" From above, Question Marks and commas are handsome butterflies with burnt orange and black markings. Their under wings, however, are cryptically colored to mimic a dead leaf. When they perch with closed wings, they seem to disappear against a background of leaf litter or tree branches. But if you examine the underside of each hind wing, you'll see a small distinctive silver hook; hence the name comma. On Question Marks, you'll find a small silver dot just below the hook -- a question mark..
If you see butterflies on a warm winter day, you're not hallucinating. And if your mind is filled with question marks, you've probably made a correct identification.