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Photograph courtesy of Michael Jeffords
THE LONG-DISTANCE FLUTTER

THE LONG-DISTANCE FLUTTER
Each fall, Illinois' monarch butterflies join an amazing migration
that stretches some two thousand miles from Canada to Mexico. We're still Learning how and why

CHASING MONARCHS:MIGRATING WITH THE BUTTERFLIES OF PASSAGE
Robert Michael Pyle, 1999
Houghton Mifflin

It's easy to start seeing things after reading Robert Michael Pyle. A spot of color at the side of the road can suddenly morph from leaf fall to willful flight. Or the other way around. Pyle experiences the same problem. But for him it's an occupational hazard. He watches butterflies for a living.

That's tougher than it sounds, it seems. Pyle, the author of The Audubon Society Field Guide to North American Butterflies, spent 57 days in 1996 trekking 9,462 miles in an effort to track and tag monarchs on their south-moving fall migration, the most amazing of all lepidopteran journeys. He chased now-you-see-it, now-you-don't blurs of orange and black down back roads, across Pacific Northwest rivers, over Western mountains and through Southwestern deserts to prove there isn't a hard-and-fast continental divide between the migratory routes of this bicoastal tribe.

It's generally believed that all West-ern monarchs overwinter on the tall eucalypts along the California coast, while all Eastern monarchs, including those that pollinate the gardens and prairies of the Great Lakes region, overwinter on ancient firs in the Mexican highlands.

This is a relatively recent observation because the roosts in the Oyamel, also called the "sacred firs," weren't discov-ered by the scientific community until 1975. And Pyle is not attempting to destroy altogether this map of the monarchs' parallel drive southward in the fall and northward in the spring. But in his latest book, Chasing Monarchs: Migrating with the Butterflies of Passage, published last year, Pyle does set out to shake prevailing wisdom. He decides he can accomplish this by following each monarch he sees wherever it goes, from western Canada south.

This is hardly a fool's errand. Pyle, a noted entomologist and naturalist, had some prior evidence. He cites instances of tagged monarchs that have crossed the divide. And he satisfies himself that some Western monarchs fly south into Mexico. Pyle's account, he might be the first to admit, manages to add detail to the known biological story, while simultaneously enhancing its mystery.

And what a mystery.
Wherever the West Coast monarchs are going, there's good reason for Mid- western pride. Illinois lies in the flight path of one of nature's most incredible feats, the Canada-to-Mexico migration of the Eastern monarch. Each fall, say Missouri conservation officials, some 100 million creatures, each weighing about half a gram, fly to a forest 75 miles west of Mexico City, though none of them has been there before. To make it, many will have had to traverse some 2,000 miles of rigorous terrain, all the while sidestepping mantises, birds and automobile windshields. They will have had to brave pesticides and herbicides sprayed over much of the country's remaining open places to find the nectar that fuels their flight. Still, they come. And, while we know where they're going, we're still learning how and why.

It's been a long wait this year, though. Through much of the summer, the Springfield area was strangely bereft of most butterflies, including the monarch. It seemed they had ceded the turf in this central Illinois neighbor-hood to the everywhere-you-look cabbage whites.

Then, on the last day of July, there they were. The bold-as-can-be blue-black pipevine swallowtail, nectaring

34 | September 2000 Illinois Issues www.uis.edu/~ilissues --- This page is also available in Adobe Acrobat PDF Image


Photograph courtesy of Michael Jeffords
Photograph courtesy of Michael Jeffords
on Verbena bonariensis, a tall annual that doubles as a lavender butterfly beacon, an aloof tiger swallowtail, the diminutive eastern tailed blue. And the monarch, big enough and bright enough to be seen from yards away, nectaring on a Buddleia davidii, the aptly named butterfly bush.

It allowed closer inpection, just enough to see it wasn’t the mimic viceroy, a smaller version of the monarch distinquished by black lines across its hind wings, yet too skittish to allow itself to be identified by gender — the males have black patches at the center of their hindwings. Male or female, this specimen was but a harbin-ger of the mass migration to come. And there was surely time to propogate one last generation. That generation, unlike the others, will not breed for months, not until the trip back from its winter roost.

If this was a female, she surely saw the orange milkweed, the host plant for her offspring, though hiding nearby were the still-tiny descendents of last summer’s garden resident, the swift and magnificent mantis. Insect carnivores are not the monarch’s only worry. Birds, too, can and will take a monarch, though the juice of the milkweed provides a mild toxic protec-tion. Most birds soon learn orange and black is distasteful. So the look-alike viceroys get a free ride of sorts.

But people are the monarchs’ most serious threat. Dangerous because they are so indifferent. Pyle is struck by how few people really see butterflies, even in mass aggregation. Though he doesn’t actually say it, if butterflies remain invisible on the human-defined land- scape, they could disappear altogether. Fortunately, it’s easy to start seeing things after reading this book.
PeggyBoyer Long

Q & A Question & Answer
Michael Jeffords
An entomologist at the Illinois Natural History Survey, a division of the Illinois Department of Natural Resources, he wrote about the monarchs’ northward spring migration in the June 1996 edition of Illinois Issues. This is an edited version of a recent conversation with Peggy Boyer Long.

Q. Illinois’ migrants are coming from states to the north?
Right, the populations are concentrated along the northeast coast and in the Great Lakes region.

Q. When will they pass through this state?
They begin amassing in northern Illinois in September. I’ve seen masses on single trees in Lee County in early to mid-September. In October in Champaign, and a little later in southern Illinois.

Q. Where should we look?
Anywhere there are resting points. In the evenings they like to come together and roost in trees and shrubs.

Q. Has there been a rise or decline in the population?
According to my map of the North American Butterfly Association’s 4th of July butterfly counts, monarchs are doing very well. In 1991, ’92 and ’93, there were less. But from ’94 through ’97, they look pretty good. Although, overall, butterflies seem to be down this year, with the exception of the monarch. The population of all butterflies seems to be down and nobody really knows why.

Q. You wrote for us a few years back and there was some concern then about the monarchs’ winter habitat in Mexico. What’s the status of that?
It’s a mountaintop. And, I have not been there, but I know there was logging going on. They have to spend time in these forests, so if the forests aren’t there, the population is going to suffer. Now ecotourism is the big thing, and that helps preserve the forests. But the tourists are disturbing the butterflies. Monarchs don’t feed there. The less active they are, the more likely they are to make it back. They’re living off fat reserves. So with too many tourists disturbing them, they end up flying around too much. They use up their reserves and then they can’t make it back. They don’t survive the winter there. It’s a Catch-22.

Q. What about the ecology for butterflies in the Midwest?
There’s not much habitat for anything. The food plant of the monarch is OK. Fortunately, milkweed is a weedy plant that ends up growing along roadsides and railroads and in ditches. One of their favorite food plants is the climbing milkweed that grows on fences and so forth.

Q. Is there anything individuals can do?
Plant a milkweed. Well, you really don’t have to plant them. They just show up. So if they show up, leave them alone. Along the edges of cornfields, along road-sides, leave them alone. Let them grow.

Q. Anything you want to add?
The monarch is our state butterfly. And probably the national butterfly. Not officially, but certainly it’s the one everyone knows about. It’s an indicator of an ecostystem’s health.

Q. When can we look for them to come back?
Oh, I’ve seen them as early as late April, early May.


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