Last year, the Monarchs covered only 1.65 acres (0.67 hectares), the smallest area since record-keeping began in 1993.
This year, the butterflies rebounded, to cover 2.79 acres (1.13 hectares), according to a formal census by Mexican environmental authorities and scientists released Tuesday.
The orange-and-black butterflies are suffering from loss of milkweed habitat in the United States, illegal logging in Mexico and climate change. Each year, the butterflies make a migration from Canada to Mexico and find the same pine and fir forests to spend the winter, even though no butterfly lives to make . . .