Winter migration of monarch butterflies to Mexico drops after one-year recovery Winter migration of monarch butterflies to Mexico drops after one-year recovery – WBNews

The number of monarch butterflies wintering in Mexico dropped by 27% this year, reversing last year’s recovery from historically low numbers, according to a study by government and independent experts released Thursday. The experts say the decline could be due to late winter storms last year that blew down more than 100 acres (40 hectares) of forests where migrating monarch butterflies spend the winter in central Mexico. Millions of monarchs make the 3,400-mile (5,500km) migration from the US and Canada each year, and they cluster tightly in the pine and fir forests west of Mexico City. They are counted not by individuals, but by the area they cover. “The reduction in the area of forest they occupied this year is most probably due to the high mortality caused by storms and cold weather last year,” said Omar Vidal, the head of the Mexico office of the World Wildlife Fund. “It is a clear reminder for the three countries that they must step up actions to protect breeding, feeding and migratory habitat.” Officials estimate the storms in March killed about 6.2m butterflies, almost 7.4% of the estimated 84m that wintered in Mexico, said Alejandro Del Mazo, Mexico’s commissioner for protected areas. The monarchs were preparing to fly back to the US and Canada at the time the storm hit. While no butterfly lives to make the round trip, a reduction in the number making it out of the wintering grounds often results in a decline among those who return the next…more detail