The winding down of summer marks the start of the annual migration of millions of monarch butterflies across North America.
According to the U.S. Fish and Wildlife Service, the migration typically runs from mid-August through mid-November, when butterflies leave their summer breeding grounds and begin a trek that spans thousands of miles.
Monarchs generally west of the Rocky Mountains head to California and Mexico’s Baja California, while those east of the Rockies travel to forests in the heart of Mexico.
Biologists say that unlike most insects, which attempt to escape the cold by hibernating and finding refuge, monarch butterflies cannot survive prolonged cold conditions.
Monarchs are able to survive the 3,000-mile trek by nectaring on late-blooming plants along the way, such as goldenrods, asters and blazing stars.
It’s important to note that, due to their short lifespan, none of the migrating monarchs have been to the migratory areas before.
Experts attribute their ability to navigate to these usual areas because of the position of the Sun and other non-climatological factors.
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The monarchs will spend time in their winter habitats until March, when they will begin their great northward migration, laying eggs on milkweed plants as they travel.
Sometimes the swarms of traveling butterflies are large enough to be seen on weather radar, with thousands able to take refuge in the same tree.
The number of sightings has significantly declined over recent decades, which scientists have tied to habitat loss, climate change, and the increased use of pesticides.
According to Monarch Watch, a nonprofit educational program based at the University of Kansas, the eastern population of butterflies has seen an 88% drop since 1996, while the country’s western population has declined by a stunning 99%.
Despite the steep decline in population, the monarch is not federally protected, but the USFWS said it is working on a proposal to add the butterfly to the Endangered Species Act.
An ESA listing would enhance protections as well as mandate recovery plans to restore the population to more sustainable levels.
Monarch fall migration map
(Monarchwatch.org / FOX Weather)
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There are several steps conservationists suggest people can do to aid the monarch population.
Experts say planting flowers that bloom into late fall, removing non-native milkweeds and reducing pesticide use could all potentially help stem further declines.
Several advocacy groups have emerged, including saveourmonarchs.org, which sends free seeds for plants that provide food and shelter for butterflies.
A monarch butterfly lifts off after drinking water January 29, 2001, at the butterfly sanctuary in Michoacan, Mexico. Some 100 million or more of the orange and black butterflies migrate annually from Canada to the forest in Michoacan.
(Photo by Susana Gonzalez/Newsmakers / Getty Images)
