Monarch Butterflies Reaching Mexico Later and in Smaller Numbers

The monarch butterflies that winter in Mexico’s forests after a journey of 5,000 kilometers (3,100 miles) across Canada and the United States are arriving later and in smaller numbers this year than in past seasons. The Monarch Butterfly Biosphere Reserve, which is located in the eastern part of Michoacan state and the western part of Mexico state, opened on Friday for the start of the season, but officials are concerned because of the small number of butterflies arriving, with their arrivals delayed by 10 days. “We are estimating, more or less, that we have about 50 percent fewer as of this time .... The figures are not very encouraging,” reserve director Gloria Tavera Alonso told Efe. Monarch butterflies (danaus plexippus) begin their migration each year in early October, flying from southern Canada across the United States and arriving in their Mexican winter homes around the second week of November. A drop of 59 percent was registered last season in the areas occupied by the colonies that winter in Mexico, the lowest level in the 20 years that officials have been tracking the migration, with the situation appearing worse this season...more