Monarch Butterfly Migration At Risk Of Disappearing

  • Monarch colonies in Mexico covered just 1.65 acres in December 2013, the lowest area in recorded history

  • WWF is calling on leaders from Canada, the United States and Mexico to agree on immediate conservation actions at the North American Leaders’ Summit in February

The number of monarch butterflies hibernating in Mexico reached an all-time low in 2013, according to data collected by the WWF-Telcel Alliance and Mexico’s National Commission for Protected Areas (CONANP). Surveys of forested area used by hibernating monarchs showed that just 1.65 acres of forest were inhabited by monarchs during December of 2013, a 44% drop from the same time the previous year. The findings represent the lowest area since surveys began in 1993.

Forest area inhabited by monarchs in Mexico is used as an indirect indicator of the number of butterflies arriving from Canada and the United States each year following a migration of more than 2,500 miles. The butterflies spend November through March hibernating in Mexico’s temperate forests.

A number of factors have contributed to a sharp decline in monarch populations in recent years, including loss of reproductive habitat caused by land-use changes and reduction of milkweed (primary food source for monarch larvae ) from herbicide use; extreme climate conditions in Canada, the United States and Mexico; and deforestation and forest degradation in hibernation sites in Mexico.

“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. “Twenty years after the signing of NAFTA, the monarch butterfly migration – a symbol of cooperation between our three countries – is in grave danger.”

WWF is calling on leaders of Canada, the United States and Mexico to agree on a plan at the North American Leaders’ Summit for immediate action to conserve the monarch migration. The Summit takes place February 19 in Toluca, Mexico.

To carry out the monitoring, bi-weekly tours were conducted through the 11 sanctuaries with historical presence of monarch colonies, determining their location, the perimeter they occupied with spatial analysis software, and temperatures.

"Since 2003, in coordination with local communities and the Mexican Government, the Alliance WWF-Telcel supports forest conservation and sustainable development in the region for the benefit of the monarch, the locals, and the tens of thousands of tourists who visit the sanctuaries every year", said Marcos Linares, Business marketing Deputy Director, Telcel.

The vast majority of monarchs that arrive in Mexico grew up eating milkweed in the United States and Canada, according to Karen Oberhauser, professor at the University of Minnesota who has studied the monarch for more than 30 years, and is a leading scientist on this butterfly. “Numerous lines of evidence demonstrate that the Corn Belt in the US Midwest is the primary source for monarchs hibernating in Mexico,” said Oberhauser. Large part of the monarchs’ reproductive habitat in this region has been lost to changing agricultural practices, namely an explosion in the use of crops that allow post-emergence treatment with herbicides. “These genetically modified crops have resulted in the extermination of milkweed from many agricultural habitats," added Oberhauser.

“In addition to habitat degradation due to use of pesticides and herbicides, recent changes in federal law in Canada have significantly reduced protection of monarch butterfly habitat across Canada", said Dr. Phil Schappert, Canadian butterfly conservationist and author who lives in Halifax, Nova Scotia, and that has worked and written on monarchs for decades. "The promotion of ‘the economy first’ practices, instead of sustainable land use practices, threatens monarch habitat”, added Schappert.

Mexican authorities effectively enforced efforts to protect the Monarch Reserve, particularly from 2007 to 2012. Those efforts, together with the decade-long financial support from Mexican and international philanthropists and businesses to create alternative-income sustainable projects and employment to local communities, resulted in the decrease of large-scale logging in the core zone of the reserve.

"Over the past 35 years Mexico has done everything to protect monarch butterfly hibernation sites, and even so the population continues to decrease. It is time that Canada and the United States implemented measures that protect the reproductive habitat and feeding grounds of this butterfly. Otherwise, this spiral of population decline will continue", Schappert concluded.

"Considering the challenges faced by the monarch butterfly and the clear evidence that their populations are declining, it is vital to mobilize as many people as possible, and that our efforts are carefully planned to help this butterfly recover, so their wonderful migration can be appreciated for many more generations", ended Oberhauser.

For Editors:

B-Roll: User: videoservices Password: pandavideo


Complete Report:


Historic Hibernating Colonies:

Hibernating Colonies Nov. 2013 - Mar. 2014:

For more information contact: Monica Echeverria, [email protected]

Of: (202) 495-4626 / Cell: (202) 378 3396

  • monarchs in sky