MONTPELIER, Vt. (AP) -Three monarch butterflies affixed with tiny tags last summer in Vermont have turned up 2,400 miles away in Mexico, the Vermont Institute of Natural Science has confirmed.

The three were among several hundred monarchs tagged in Vermont last year as part of an effort to track their migration to their wintering grounds in El Rosario, Mexico, said VINS consulting naturalist Bryan Pfeiffer.

“A monarch I held in my hand flew all the way to Mexico,” he said. He tagged one in his yard in Plainfield in August, and joined a VINS staff scientist, Kent McFarland, in tagging more during a daylong demonstration at the VINS Nature Center in Quechee in September.

“This is one of the great natural events in North America, the movement of millions and millions of monarch butterflies south through the continent to Mexico,” Pfeiffer said of the annual fall migration.

The Vermont butterflies tagged and recovered were the second, third and fourth monarchs ever found to have traveled all the way from Vermont to Mexico; the first was in 1999, Pfeiffer said.

The VINS tagging effort was done in cooperation with Monarch Watch, a national group based at the University of Kansas that is devoted to butterfly research and preservation.

Most of the tagging occurs where most of North America’s monarchs are in the warmer months: the Great Plains, Pfeiffer said.

The Monarch web site says about 105,000 butterflies were tagged as they migrated south in the fall of 2001.

In what was considered a very good year, fewer than 2,000 of the tagged butterflies were recovered.

Many monarchs die on the trip, Pfeiffer said, often ending up as windshield splatter. “The real prize is to have a monarch you’ve tagged turn up in Mexico,” Pfeiffer said.

Pfeiffer provided the following account of a monarch’s life:

Females die after they lay eggs on milkweed, out of which caterpillars hatch. The caterpillars later form a chrysalis, which is emerald green with gold highlights. Eventually the butterfly breaks out of the chrysalis. The monarch life cycle is usually just a few weeks, Pfeiffer said, and the insects “breed their way north” in spring and summer, taking a few generations to reach Vermont.

The last generation of monarchs born in the north in late summer and early fall take a different course in a life that lasts longer. They migrate from throughout North America to wintering grounds in Mexico, beginning the journey north again in early spring.

The research is taking on new urgency as woodcutting by people in the mountains west of Mexico City is thinning the mountain forests where the butterflies spend their winters.

“The most effective way to harm a species is to harm a habitat that it really depends on,” Pfeiffer said.

Pfeiffer said learning that a butterfly he had tagged had turned up in Mexico gave him a new sense of connectedness. “Suddenly Mexico matters more to me.

There’s a connection between Plainfield, Vermont and El Rosario, Mexico. There’s a connection between a nature preserve in Quechee, Vermont, and El Rosario, Mexico.”