The first monarch butterflies have arrived at their wintering grounds in the mountains of central Mexico almost a week later than usual, Mexico’s Environment Department said Wednesday.
Millions of monarchs make the 3,400-mile (5,500-kilometer) migration from the United States and Canada each year.
The butterflies usually arrive by Mexico’s Nov. 1 Day of the Dead holiday, and local residents long associated their return with the souls of the dead returning to their homes.
But this year, the Environment Department said the first butterflies weren’t seen in the mountain reserve west of Mexico City . . .
