The iconic black and orange-yellow migratory butterflies have been dying off over the past several years due to habitat loss.
But this winter, the number of monarchs hibernating in southern Mexico has rebounded, according to a December survey. Winter colonies covered about 10 acres of forest this winter, up from around three last winter.
Good weather conditions during the migration to Mexico were a factor, but more important were habitat restoration efforts north of the border.
In the US, volunteers and government agencies have focused on planting a milkweed corridor along the migration route.
Milkweed is essential to the monarch reproductive cycle, as females will only lay their eggs on milkweed plants and larvae eat it before turning into butterflies.
“The news is good, but at the same time we shouldn’t let our guard down,” said Omar Vidal, director of the World Wildlife Fund in Mexico. “Now more than ever, Mexico, the United States, and Canada should increase their conservation efforts to protect and restore the habitat of this butterfly along its migratory route.”