Monarch butterflies are back in Mexico this year, after an alarming 75% drop in their numbers last year. A survey released today found that butterfly colonies encompassed 9.9 acres—a significant increase from the 4.7 acres that alarmed experts last year, reports the AP. The figures are "encouraging" and "show a trend toward recovery," says an official with World Wildlife Federation Mexico.
Still, the population is still down drastically from 2009, when it covered nearly 20 acres, or its heyday in 1997, with 45 acres of butterflies. "Fluctuations in insect populations are normal in nature," the study's sponsors said. "With regard to the monarch butterfly, these fluctuations could be due mainly to climatic conditions,"including harsh winters. But experts point to deforestation near the butterflies' wintering grounds as another key factor.