Each fall monarchs set out on a 5,000-kilometre journey to their wintering sites in the mountain forests of Mexico, where they cluster together from late October through March. The area of forest covered by the endangered butterfly is used by scientists to track monarch populations.

During the past two decades, WWF has seen a dramatic and sustained decrease of the area occupied by monarchs on their wintering grounds, from almost 18.2 hectares of forest at their peak in 1996 to just 2.5 hectares in 2017.

With the longest migration of any insect in the world, there are many places where monarchs can become vulnerable. The Gordon and Patricia Gray Animal Welfare Foundation supports the WWF's initiatives to conserve the Monarch's habitat across its migration routes -- in Canada and the United States where monarchs breed and spend their summers, and in Mexico where they spend the winter.