Fall is officially around the corner, and that means that we are about to see a lot more monarch butterflies on the move. According to a report from the Statesman Tribune, millions of the butterflies will begin a 3-month migration from Canada, through the United States, and deep into the forests of Mexico. The migration will span over 3,000 miles.

Monarch butterflies make this trip once a year, but reports show that their population numbers are seriously threatened. Since 1997, the number of monarchs embarking on this massive journey have decreased from one billion to 56.6 million.

Monarchs are a highly specialized insect, and they only really have one habitat and food source – milkweed. The plant, found throughout the entire North American continent, is rapidly being wiped out by glyphosate, a commonly used herbicide, most notably as the main ingredient in Monsanto’s Roundup.

According to Rebecca Riley, an attorney with the National Resource Defense Council, the population of monarchs that fly to Mexico to wait out the winters has dropped over 90 percent in the last two decades. The monarchs follow a path named the “Butterfly Highway,” and become thrown off their path when they run into a break in their milkweed habitat.

The EPA announced that it will launch a five-year study on the effects of roundup on more than 1,500 endangered species, including the monarch. But many fear that this doesn’t leave enough time for the monarchs to rebuild their populations. To save the monarch butterflies, people should be focused on protecting habitat and planting more milkweed. And of course, take it easy with the roundup.