Experts in Mexico said Tuesday there is a tentative sign of hope for the mass migration of monarch butterflies, whose numbers dropped to their lowest level ever last year.
The head of Mexico's nature reserves, Luis Fueyo, said the first butterflies have been seen entering Mexico earlier than usual this year.
Fueyo said it is too early to say whether butterfly numbers will rebound this year from a series of sharp drops, but noted "this premature presence could be the prelude to an increase in the migration."
He said the first butterflies have been sighted in the northern border . . .