NORTHLAND NATURE: Tiger swallowtails arrive in June
As we moved through the long and near record-breaking winter, we may have wondered if summer would ever come. But here we are at the summer solstice, the first day of summer. It is also the time of greatest sunlight: a sunrise shortly after 5 a.m. and nearly 16 hours later, a sunset a few minutes after 9 p.m.
June is also our wettest month. The recent rains we’ve been getting attest to that statistic. And temperatures are often warm, maybe even hot. Light, warmth and moisture all make for great growing conditions and that is exactly what we’ve seen so far this month, and it continues now in late June.
Trees have leafed out, put forth new growth, flowered and produced pollen; some have even formed seeds in recent weeks. The wildflower blossoms have proceeded from the shady forests to the more-lighted edges. Now the most blooming takes place in the open country of roadsides and fields.
But the growth of this month goes far beyond the plants. Birds, many of which arrived back here in May, have been nesting and caring for the new members of their families. Young rabbits and squirrels are in our yards while a fawn hides in the woods. The summer frogs, mink frog and green frog, have begun calling along with the persistent buzzing of gray tree frogs. In an opposite trek, turtles leave water to lay eggs on land.
But maybe the most abundant animal growth now is among the insects. It’s hard to live in the Northland in June and not notice insects. We don’t even need to go in search of them. They come to us. Mosquitoes and black flies are in the reproductive phase of their lives now. The females need a meal of blood, a source of protein, to help them produce eggs. Many animals are selected for this meal of blood, humans included. Because of these annoying bugs, it may be easy to think that we’ll avoid all insects at this time.
But there are many more of these six-legged critters than just the pesky ones. June days also have flights of dragonflies and damselflies (both of which are predators of mosquitoes), butterflies and sphinx moths. At night, the illuminated flight of fireflies takes place in yards and meadows. We don’t appreciate all insects, but the nocturnal fireflies and diurnal butterflies are two that most people like.
Butterflies usually begin their appearance in the region with the waking of a couple of hibernators. Most years this happens in March; this year it was April. In May, others show up: a tiny blue spring azure, white cabbage and yellow sulfurs. As we reach the end of May each year, I look for a couple of small ones, the orange-black skippers, and two large butterflies, monarchs and tiger swallowtails.
While the migrant monarchs are black-orange, tiger swallowtails are very obvious in their attire of black and yellow. Monarchs have suffered in recent years, so it was a great relief when I noticed the first returnee on May 29 and several more in subsequent weeks.
Tiger swallowtails, which like most butterflies do not migrate, are a regular part of the June fauna, emerging in late May and gone in July. For some reason, these large and colorful butterflies are abundant this year, adding much to the scene in many Northland yards as they visit our lilacs and other flowers. (I saw nine at one time recently on the blooming lilac in the yard.)
It is the black stripes on the yellow wings that put tiger in its name. The “swallow” tail is from a growth extending from the hind wings. (Barn swallows have long tail feathers.) This butterfly, named for a mammal and a bird, is one of the largest in our region.
Swallowtails are a rather big group of butterflies in much of the country. We have only two kinds, the dark black swallowtails that make sporadic appearances and the regular tiger swallowtails. Our swallowtail is correctly called the Canadian tiger swallowtail, while in the south part of the state a larger eastern tiger swallowtail prevails. Both kinds have red and blue spots and markings, mostly on the undersides, along with the black and yellow.
Adults feed on nectar from a variety of plants that are in bloom at this time. They have also been observed sitting on the ground as they take minerals and moisture from the wet soil. Many may congregate at these puddles. Eggs are deposited among the trees. Caterpillars feed on the leaves of lilac, aspen, birch, willow, cherry, maple or basswood, often eating at night. In fall they form a chrysalis to survive the winter. During next June, we’ll see the offspring of this population that is so prevalent now as we start summer.
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.