Butterflies make partial comeback in Mexico

Butterflies make partial comeback in Mexico
MEXICO CITY – The number of monarch butterflies migrating from Canada and the U.S. to Mexico has increased this year, a hopeful sign following a worrying 75 percent drop in their numbers last year, experts reported Monday.

The total amount of forest covered by the colonies — millions of orange-and-black butterflies that hang in clumps from the boughs of fir trees — more than doubled from last year's historic low.

But concerns persist about the monarchs' long-term survival, because their numbers remain well below average.

This winter, there are 9.9 acres (4 hectares) of colonies, more than double the 4.7 acres (1.9 hectares) last year, the lowest level since comparable record-keeping began in 1993.