Monarch Butterfly Migration Disappearing, WWF Says

Monarch butterfly migration might soon become a thing of the past, conservationists have warned. A new survey has found that the number of monarchs arriving in Mexico dropped significantly in 2013.

The survey conducted by World Wildlife Fund-Telcel Alliance and Mexico's National Commission for Protected Areas (CONANP) found that the butterflies just covered 1.65 acres of forest area in 2013, which is the smallest area yet. In 2012, these butterflies occupied about 2.94 acres.

End of an incredible migration?

Each year, thousands of monarch butterflies travel over 2,500 miles to reach the temperate forests of Mexico.

North American monarchs are the only known butterfly species to travel such a long distance, according to National Geographic.

Several factors- such as climate change, loss of habitat, changes in agricultural practices- have contributed to the fall in the number of monarch butterflies. Farmers in the U.S are now using herbicides to fight milkweeds, which are a major food source for migrating monarchs.

"The combination of these threats has led to a dramatic decline in the number of monarch butterflies arriving to Mexico to hibernate over the past decade," said Omar Vidal, WWF-Mexico Director General, according to a new release. "Twenty years after the signing of NAFTA, the monarch butterfly migration - a symbol of cooperation between our three countries - is in grave danger."

"The butterfly as a species isn't in danger of extinction," Vidal added, according to Washington Post. "What is in danger of disappearing . . . is the migration of the monarch from Canada through the United States to Mexico."

Forest area is used as an indirect way of estimating the population size of the butterflies. In the present study, conservationists carried out bi-weekly surveys of 11 sanctuaries that are known to house these monarchs.