CNHM Director of Education
My mother is a passionate gardener, and she knows all of her plant friends by name. Others have birds at their feeder, or squirrels, chipmunks, or bears that they know and call by name. A Museum member called to report her repeated observation of Compton’s tortoiseshell butterflies this week. The following day, I was out scouting Mount Telemark for a hike up the big hill, and saw a variety of woodland butterflies as well. In northern Wisconsin, we have several woodland butterflies that are worth getting to know by name. Please let me introduce you to the Compton tortoiseshell, northern pearly-eye, common wood nymph, and little wood-satyr, all woodland delights.
The Compton tortoiseshell butterfly is more common in our northern counties. It belongs in a group of butterflies called true brush-foots because they appear to have only four legs. Their front forelegs are reduced in size, usually hairy and resembling brushes. Adults emerge in July, in deciduous woodlands, trails, openings, and woodland edges. From above, this butterfly looks mostly a rusty orange and black butterfly, with single white marks near the edge of each wing. The wings have sharper angles with a small tail on the hind or lower wing. From below, the butterfly could be mistaken for tree bark, as they have a camouflaged coloring with a silvery mark in the middle of the hind wing. Last year, Compton’s tortoiseshell butterflies were seen in higher numbers, as the species does have periodic fluctuations in its populations, being abundant for years and then disappearing for other years. Its common name is from a famous English naturalist, Philip Gosse, who studied the butterfly while living in the town of Compton in Quebec in the nineteenth century. These butterflies overwinter as an adult, mating in the spring for a July emergence.
The northern pearly-eye butterfly is a common woodland species rarely found in openings. It is also commonly seen in woodlands, woodland edges, or while we are hiking down a woodland trail. This species is best identified by its brown coloring with lighter areas on the fore or front wing, and two obvious dark spots through both wings. Other spots trail down the hind wing. From below, the spots are circled with a yellow, brown, and white ring. The hind wing spots have a small white dot in the center. This species may be more difficult to identify with its fast, erratic flight that sometime ends further away against a sunlit tree.
The common wood nymph may be the most common butterfly in Wisconsin in a woodland habitat. Its lack of color makes it less conspicuous, but still worth looking for. This species is usually seen from below, so its underside has two large eyespots with a yellow ring on its fore wing. It is most often found in open fields near woodlands. This is the most common satyr butterfly that can be seen, and the best time to catch a flash of this butterfly is in July.
The less common little wood-satyr is often mistaken for a northern pearly-eye, but the little wood is much smaller, and found flying within only a few feet of the ground. They also fly more slowly, looking almost lazy in its flight. From above, it has two obvious eyespots on the fore wing and on the hind wing, ringed with white. When seen from below, it has two eyespots on the fore wing, while the hind wing has two eyespots and several smaller eyespots. There are also two darker lines across both wings. This species is also found earlier in the season, more in June than July.
My passion in nature is for butterflies. I try to know all their names, and take great joy in learning more about them through observation. These four butterfly species are all so amazingly camouflaged that I find it difficult sometimes to identify them. I use little things to help me remember them: Compton’s – orange and black with white; pearly-eyed – two main spots, trailing spots, with white dots in the center; common wood nymph – obvious large eyespots on the forewing with yellow rings; little wood satyr – smaller with two spots on top (forewing) and two on bottom, and lazy flight near the ground. May you all get to know these butterflies, and enjoy these woodland delights!
Nature Watch is brought to you by the Cable Natural History Museum. For 40 years, the Museum has served as a guide and mentor to generations of visitors and residents interested in learning to better appreciate and care for the extraordinary natural resources of the region. The Museum invites you to visit its facility and new exhibit, On Lake Owen: The Art of Walter Bohl, in Cable at 13470 County Highway M or on the web at www.cablemuseum.org to learn more about exhibits and programs.