FLOATING FLOWERS IN THE SKY The challenge and importance of counting butterflies. By Shane Sater
DELICATE DAZZLER The Melissa blue butterfly lives throughout Montana in wet meadows, moist streamsides, open woodlands, parks, and gardens.
16 | JULY–AUGUST 2020 | FWP.MT.GOV/MTOUTDOORS
LEFT TO RIGHT: RICHARD J. JACKSON; JESSE LEE VARNADO
T
he parking lot at the main Rattle- them requires stealth and lightning-quick band running along the back of its black snake trailhead near Missoula is reflexes. In the dappled light of a small wings. DuBois identifies it as a Milbert’s bustling this July morning. An meadow, I spot one resting on a wildflower. tortoiseshell, an uncommon species this unusual group has gathered at one I swing my net and quickly twist the handle time of year, she says. We mark it down in end, carrying insect nets, field guides, to close the bag. The butterfly flutters a notebook and let it flutter away. and binoculars. These butterfly watchers are taking part in the BUTTERFLY BASICS annual Five Valleys Butterfly Butterflies are shape-shifters. Count. With a forecast for sunny Each starts life as an egg, hatches skies and highs in the upper 70s, into a voracious caterpillar, rests the weather looks promising. as a comatose pupa, then trans“Butterflies are solar-powered. forms into a winged wonder. They need sunlight to warm Montana hosts roughly 200 them up so they can fly,” says butterfly species of remarkable Kristi DuBois, a former regional diversity. Many survive just a few Nongame Wildlife Program weeks as adults, while others coordinator for Montana Fish, may live as long as eight months. Wildlife & Parks who has led this Some spend the winter as eggs count for the past 12 years. or pupae. Others hibernate as Our goal is to identify all the adults, one-fifth of a gram of butterflies we see. A few species insect somehow surviving are easy to distinguish, even at Montana’s brutal cold. A few, like a distance. Others are much the monarch and painted lady, harder. Using light mesh bags on can migrate hundreds of miles in The Milbert’s tortoiseshell is a common Montana butterfly found statewide in gardens, parks, wet meadows, and moist streamsides. four-foot handles, the plan is to spring and fall to and from southcatch, examine, and release. ern wintering areas. Butterflies are surprisingly wary. Netting inside, uninjured though no doubt surPlants, consumed in the caterpillar stage, prised. Another participant helps me gently are essential for butterfly development. transfer it to a collapsible mesh box. Some butterfly caterpillars are generalists, Shane Sater is a biology student at Carroll Through the plastic viewing window, the feeding on a variety of vegetation. Others College in Helena and a part-time employee with the Montana Natural Heritage Program. butterfly is gorgeous, with a flame-colored are specialized. The Milbert’s tortoiseshell MONTANA OUTDOORS | 17
18 | JULY–AUGUST 2020 | FWP.MT.GOV/MTOUTDOORS
NUMBERS GAME In the Missoula area, and at the MPG Ranch, Glacier National Park, and Yellowstone National Park, volunteers count different species of butterflies each summer. The counts, along with hundreds of others nationwide, are coordinated by the North American Butterfly Association. Information from the surveys helps scientists understand population trends and identify threats to butterflies.
WHERE TO FIND THEM A few clouds are moving in, but the air above the meadows remains busy with butterflies. The winged insects seem to dwindle along stretches of trail where trees, and shade, close in. The key to finding abundant butterflies is to seek out sunshine and diverse host plants, DuBois says. Recently burned forests,
where fire was not too severe, are usually great sites. “The first few years after a fire you get all this sunshine and, with it, a big flush of shrubs, forbs, and grasses—all excellent butterfly food plants,” she explains. Meadows, streamsides, and edges between different habitats are other likely spots. Males concentrate on hilltops and in
PHOTOS: MARIROSE KUHLMAN
I caught likely grew up eating nettles. The Rocky Mountain dotted blue, a tiny meadow gem, eats only buckwheats—from a single genus of native plants. Other species consume junipers, lupines, mustards, violets, willows, and grasses. “If you don’t have the right larval food plants, you won’t have butterflies,” DuBois says. Most caterpillars end up as food for something else. “They’re full of fat and are very nutritious,” DuBois says. Many songbirds, even seed-eaters like lazuli buntings, fatten their nestlings on caterpillars. As for adult butterflies, most survive on flower nectar sipped with their tongue, which works like a straw. A butterfly, which the British poet Rudyard Kipling called “thou winged blossom,” gets its colored wings from millions of tiny scales that reflect light in different ways. The category of butterflies known as blues are sky-blue or brownish, quarter-size, and abundant. Sulphurs are yellow and fly quickly. Wood-nymph butterflies wear brown camouflage with unexpected bullseye markings under their wings. Swallowtails are large, striped in black and yellow. In the Missoula-area meadows, today’s volunteers find dozens of orange butterflies in the skipper family—all tiny, active, and triangular winged. Most are the accidentally introduced European skippers. They showed up around Missoula sometime after 2002, and in recent years have become one of the most commonly observed species on the Five Valleys count. Sunny skies bring out the butterflies. As longtime butterfly counter Jim Brown of Missoula says, “So much of their life is inconspicuous.” Eggs, caterpillars, and pupae live out of sight of most people. Even as brightly colored adults, butterflies take cover if it’s cloudy, rainy, or cold. “What you find on a given day depends so much on the weather,” Brown says. Some months are better than others for viewing certain species. In early June, for instance, Brown sees many spring azures. “But by July they’re very uncommon at this elevation,” he says. Other butterflies, like the woodland skipper, are just starting to appear in July. In another month, they’ll be common and eventually disappear from sight.
CLOCKWISE FROM TOP LEFT: DOMINICK SPERANZA; STACY THORNBRUGH; GAIL MOSER; DOMINICK SPERANZA; JESSE LEE VARNADO; ELIZABETH MOORE
COLORFUL CROP SUSTAINERS Butterflies are essential pollinators. From alfalfa to apples, pollinators are key to the production of about 150 food crops worth an estimated $10 billion in the United States each year, according to the U.S. Department of Agriculture. Montana is home to roughly 200 butterfly species. Clockwise from top left: woodland skipper, cabbage white, mourning cloak, anise swallowtail, Christina sulphur, and Boisduval’s blue. Many survive just a few weeks as adults, while others may live as long as eight months.
MONTANA OUTDOORS | 19
20 | JULY–AUGUST 2020 | FWP.MT.GOV/MTOUTDOORS
CLOCKWISE FROM TOP LEFT: PAUL LALLY; RANDY BEACHAM; CAROL POLICH; AARON BARTOSIK; DOMINICK SPERANZA; DAN ELLISON
DAZZLING COLORS Butterflies are covered in millions of tiny scales that reflect light in different ways to produce the insects’ vibrant and diverse colors and patterns. Part of the beauty of butterfly sightings comes from the flowers that they move among, feeding on nectar sipped through their strawlike tongue. In their caterpillar stage, butterflies eat plants—often only specific species—growing fat and providing nutritious food for birds and other wildlife. Clockwise from top left: Weidemeyer’s admiral, spring azure, snowberry checkerspot, pale swallowtail, gray hairstreak, and painted lady.
ravines searching for mates. Other males fly Now young and middle-aged forests have up and down a trail, patrolling a territory. increased. That’s been better for some Since most adult butterflies feed on nectar, wildlife—elk, for instance—but worse for flowers are good places to check. Mud pud- others, like butterflies. “The whole butterfly dles also attract surprising numbers—yes, habitat picture is related to the whole butterflies get thirsty. Some species also wildlife habitat picture,” DuBois says. While gather on cowpies and wild animal scat. hundreds of native insect species have sufDuBois points out that butterfly habitat fered from the habitat changes wrought by is changing in the Missoula foothills. Nox- lack of fire, most invertebrates are difficult ious weeds have displaced native grassland to see. “But butterflies are a highly visible wildflowers such as lupines and violets. For- part of the invertebrate community,” est openings and grasslands, historically DuBois says. “They’re easy to monitor.” kept open with wildfire, are filling in with young Douglas firs. For thousands of years THE IMPORTANCE OF COUNTING in the Missoula area, DuBois explains, fires In 2013, botanist and butterfly enthusiast periodically raced through forests, creating Marirose Kuhlman started a butterfly count at a mosaic of open and treed areas. “You’d the MPG Ranch near Florence. The annual have seen more grasslands, more meadows, events have become both social and scientific. and also more old-growth forests.” “Not only do they provide good information, Ancient trees were less likely to ignite in but it’s a great way to connect with other the fast-burning fires that shaped the region. people and get better at learning. Some
counters attend every year,” Kuhlman says. Butterfly counts also take place at Glacier and Yellowstone National Parks, part of the roughly 450 counts across North America each summer coordinated by the North American Butterfly Association (NABA). The summer counts are a butterfly version of the annual Christmas Bird Survey run by the National Audubon Society. The NABA’s yearly reports include important information about the geographical distribution and relative population sizes of butterfly species. By comparing results across years, scientists can monitor butterfly population trends and study the effects of weather and habitat alterations on various species. “Like with managing all wildlife, annual population monitoring is vital for butterflies,” DuBois says. “They’re definitely fun to look at, but it’s important that we count them, too.”
More about Butterflies
BOOKS A Golden Guide: Butterflies and Moths, by Robert Mitchell and Herbert Zim
MARIROSE KUHLMAN
A Swift Guide to Butterflies of North America, by Jeffrey Glassberg ONLINE Find a butterfly count: naba.org/counts/us_mx_map.html Butterfly identification: butterfliesandmoths.org/ Species profiles http://fieldguide.mt.gov/
The variegated fritillary is found in parts of Montana in fields, grasslands, pastures, and open woodlands. In North America, the species ranges from central Saskatchewan to central Mexico. MONTANA OUTDOORS | 21