Amazing monarch butterflies in full force in Maine this summer

Flying from Maine to Mexico is a serious endeavor, whether you go by jetliner or feathered wing. Maine-born monarch butterflies flutter the 2,000-mile journey south to their tropical wintering grounds on paper-thin wings, motored by a body the size of peanut.

Butterfly enthusiasts in Maine are cheering them on as the largest crop in recent memory heads south this month and next.

According to Judy Walker, staff naturalist at Maine Audubon, the abundance of monarchs this year is likely a result of high reproductive success in Mexico and points south -- a function of favorable weather and a good crop of milkweed, the butterflies' preferred feed.

"There are way more around this year, everyone has been commenting," Walker said. "This should be the largest migration since 2001."

Chuck Cleaver, an avid birder and fisherman from Skowhegan, has been watching monarchs migrate for decades. His fascination with the butterflies began as a child, when his mother helped him mount a preserved monarch in a frame. For the past 15 years, he and his wife Dot have kept diligent records.

Retired Maine Forest Service entomologist Richard Dearborn, a lifelong monarch enthusiast, agrees. He counted more than 100 on a recent walk through a brushy patch of field near his home in Mt. Vernon.

"I've watched monarchs in Mt. Vernon since 1966," Dearborn said. "I have never seen monarchs this abundant. It's just phenomenal. I'm not sure it can be attributed to any one thing, just a natural combination of factors that have worked in concert for the butterflies."

This natural extravaganza is bittersweet. The first of Maine's monarchs begin their epic migration to Mexico and central America this month -- never to return to Maine again.

The migration alone is miraculous in scope. But how these creatures find their way south without GPS, a map or compass is a mystery that may never be solved.

Walker said the monarch butterfly's northward migration in early spring follows the emergence of milkweed, a plant found across most of North America. As it blossoms south to north, the butterflies make their way into the U.S. from their central American wintering grounds.

"The monarchs that we see here in Maine didn't come directly from Mexico. These are their offspring," Walker said.

She said the first "flight" of monarchs leaving their wintering grounds in the spring stops somewhere in the southern United States to breed. Their offspring develop from eggs before continuing on to the next leg of the migration, eventually reaching Maine, near the northern terminus of the monarch's range.

"These butterflies were hatched in Maine this summer. They've never been to Mexico," Walker said. "They don't learn to migrate or even meet their parents, like shorebirds or ducks might. It just boggles the mind."

The Cleavers decided to see it for themselves, so in 2000, they made the voyage to Mexico by plane, pickup truck and finally, on foot.

Even with the latest in modern technology, the trip was tedious -- never mind the language barrier. They used the Internet to find their tour guide, and jet and combustion engines to shorten the trip.

"We were absolutely blown away when we learned about their migration," said Chuck Cleaver.

He describes the wintering grounds as stunning -- fields of brilliant orange enflaming the woods and sky.

"It's just incredible to see them there, and to think some may have come from Maine," he said. "They coat the trees there. Limbs were broken they were so crowded onto them. It's almost a religious experience."

Monarchs winter in the mountainous Michoac㌻ province of Mexico, at elevations above 10,000 feet. They specifically seek out the oyamel fir tree, which provides shade, food and cover for the first generation of butterflies that will emerge to migrate north in February and March.

According to entomologist Dearborn, it isn't until months later -- usually June -- that the great, great grandchildren of these Mexican monarchs begin to filter into Maine, only to leave south again in late summer and early fall.

Monarchs have few natural predators, but they are still threatened -- largely by a loss of habitat both along their migration routes and in their southern wintering grounds. They are also easy prey for automobiles, spiders and disease, quite common in insect populations, particularly butterflies.

In Mexico, the monarch's favored oyamel tree is under attack by illegal logging, even in sanctuaries dedicated to the butterfly.

While Mexican officials and environmental groups are trying to stop the practice, it's increasingly threatening the limited supply.

The threats make this year's booming population even more impressive -- and inspiring.

"I would never have expected to have such an incredible year with all the disastrous happenings at overwinter sites," said Dearborn.

But he noted, this isn't the first time that monarchs -- a species that's survived for many thousands of years -- have faced adversity.

"They've been around for a while. They must be pretty resilient to change to have survived this long," he said.

Walker said monarchs aren't quite as defenseless as their carefree demeanor might bely. Their beloved milkweed not only provides sustenance, but it wards off predators as well.

"They don't get eaten by wildlife like birds," Walker said. "The caterpillars feed exclusively on milkweed, and a toxin in the milkweed makes them taste bad as caterpillars and adults, so they really have very few natural predators."

Walker said Maine Audubon tags monarch butterflies each year as part of an ongoing program to monitor the butterflies and attempts to better understand their habitat, their migration and the threats to their survival.

The tags are available in a kit from www.monarchwatch.com. Each tag is an adhesive sticker the size of a pencil eraser. It affixes to the underside of the monarch's wing.

The hope is that monarch enthusiasts on the other end of the migration will happen upon a tagged monarch, capture and report it.

To date, only one tag from Maine has been returned. That butterfly had flown to Belize.

"Mother Nature has a lot more cards up her sleeve than we have ability to figure it out," Dearborn said.

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