Tracking This Year's Dismally Small Monarch Migration

In the summer of 2011, a small band of Ontario scientists set out to perform the most ambitious survey ever attempted of the imperiled monarch butterfly. Leading the fieldwork was Tyler Flockhart, a Ph.D. candidate at the University of Guelph, who trekked nearly 22,000 miles through the United States and Canada to bag and tag hundreds of butterflies, which were then put under a lab analysis to determine their birthplaces.

"As far as I know, it's the broadest sample of monarch butterflies through an entire breeding season across North America," Flockhart said recently. The results of the endeavor confirmed what entomologists have fretted about for years: Everyone's favorite butterfly seems to be fluttering on the road toward extinction. "They've been declining steadily," said Flockhart, to the point that 2012 their population numbers in their Mexican winter home were at the lowest point on record.