Spring On the Wing: Mourning Cloaks Are Flying Again
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The arrival of spring at Harmony Hill is a complicated matter. Not that the added chores and activities around the garden and pastures make things confusing, as that actually gives clarity to the days here. No, it is that Mother Nature in our region doesn’t necessarily follow the calendar to begin her awakening from the winter slumber. Just a look at the weather and temperatures this past month and it is easy to understand why there are leaf buds popping out everywhere we look. Bluebirds have already begun inspecting the nest boxes and the daily concert of frogs along the creek and the edges of the pond are getting louder each morning.
One of the surest signs that winter’s grip on the landscape is breaking can be seen flitting in the warm sun; a glint of contrasting dark and light, of iridescence and matte colors, of life lifting from the lifeless cold of the short days of the previous season. On beautifully graceful wings, sometimes worn and tattered from a lifespan far longer than any of its relatives, the Mourning Cloak (Nymphalis antiopa) is the first of the butterflies at Harmony Hill to take to the air, long before March 20th arrives.
Unmistakable in appearance, the darkness of the wings surrounded by brilliant whitish yellow of the Mourning Cloak is exactly where the common name comes from. The wings resemble a person in deep mourning, cloaked by a dark garment to show sadness and loss. In parts of Europe, where this species is also commonly found, the practice of layering in dark clothing to express grief can still be seen in modern culture. The wearing of a dark dress, suit, or even veil to a funeral or wake is an extension of that. And that is what was seen in the colors and pattern of the Mourning Cloak Butterfly.
Besides being documented at Harmony Hill this species is found across North America, Central America, parts of South America, as well as parts of Asia and, as previously mentioned, through much of Europe. Just as at Harmony Hill, Mourning Cloaks are often the first butterflies seen each year. In its northerly habitats, it is extremely common to see this species fluttering about while snow is still very much on the ground. Let’s look at how this species is first out of the gate.
The answer is quite simple. This butterfly hibernates. And it is quick to awaken when temperatures begin to rise. It can very often be seen on the first warm days of the year, then retreat to a safe place to wait out any cold spells that may interrupt the march towards consistently warm days.
A member of the Brush-footed Butterfly (Nymphalidae) Family, Mourning Cloaks use two important tools to survive the coldest months. They overwinter by finding shelter beneath exfoliating bark on trees, in clusters of dead leaves clinging to twigs, and even in old, abandoned woodpecker cavities. Furthermore, members of this family are cryptically colored and use that camouflage to elude the view of potential predators. When at rest with wings folded, Mourning Cloaks can easily be mistaken for a burned piece of bark or wood.
Overwintering is not a strategy taken by most of the adult butterflies at Harmony Hill. To the contrary, most species of butterfly don’t make it to winter here, much less through the winter. If the adults of most species aren’t gone by the first hard frost, that is the final event of their short lives. That is far from the case for Mourning Cloaks; however, as this species can find shelter and survive long periods of subzero temperatures. That extreme ability to survive frigid weather is quite useful in northern latitudes, but is not something they must endure at Harmony Hill.
Another behavior seen in many of the Brush-footed Butterflies that Mourning Cloaks are known for is that they overwhelmingly prefer to lap up moisture and nutrients from puddles, decaying meat, scat, and sap from trees, instead of visiting flowers for nectar. It is not unusual to see Mourning Cloaks hanging around the holes drilled by Yellow-bellied Sapsuckers, taking advantage of the sweet liquid made available by the woodpeckers. If you think about it, that makes perfect sense, doesn’t it? Sap starts flowing in the trunks of trees when the temperatures warm up and that gets the sapsucker holes oozing, providing our early spring Mourning Cloaks with a food source!
While having the ability to survive the winter gives this species a leg up when it comes to being able to find food before most wildflowers are in bloom, it doesn’t necessarily come without its dangers. Their camouflage is effective, but not fool proof. Predation does happen. Sheltering out of the wind and where the cold doesn’t bite so hard is handy, but if the winter is particularly brutal or long, then the adults that hibernate may not make it. And the adults enter into hibernation in the condition they were in at the end of the warmth of last year. If they had damaged wings or other injuries, that physical impairment will still be there when they emerge. That might make them ready prey for predators. And the list of predators of this butterfly is long! From reptiles, amphibians, birds, and mammals to fellow insects, such as parasitic wasps and flies, Mourning Cloaks face a gauntlet of critters looking to take advantage of them as food or hosts for their own larvae!
Speaking of larvae, we know adult Mourning Cloaks feed on the fluids of trees, decaying meat, scat, and moisture on the ground; but, what of the caterpillars? At Harmony Hill, Mourning Cloak caterpillars use Black Willow (Salix nigra) and American Elm (Ulmus americana) as host plants more than anything else; but, Hackberry (Celtis occidentalis) is another host plant they will utilize.
This spring, we will enjoy seeing Mourning Cloaks as they fly around the creek and forests, knowing they will be mating and laying eggs soon. And we will be thankful for those adults that overwintered, knowing their 10–12-month lifespan will soon be over. We will delight in their beauty and grace, whether in flight or perched as they get much needed nutrients from anything but flowers. More than anything, we will be thankful as they herald the arrival of spring. Some have American Robins as their icons of spring. Of the many plants and animals we know foretell longer and warmer days, Mourning Cloaks are one of our favorites at Harmony Hill! No calendar needed when we see them out and about!