Over the last two decades, 90 percent of monarch butterflies have disappeared. Poof.

The species known for migrating more than 2,500 miles to and from its hibernating spots in the Mexican mountains and parts of California plays a crucial role (along with bees) pollinating the North American food supply, but it has been ravaged by climate change and our addiction to herbicides. Milkweed, the plant on which monarchs like to land and lay their eggs, has been wiped out in many areas because of deforestation, drought, and herbicide application, a development believed to be a major contributing factor in monarchs’ decline.

But there may be good news: The monarchs are coming back.

At a press conference this week, the World Wildlife Federation announced that monarchs covered about 10 acres in Mexican forests this winter—a space about three times as big as last year’s, according to the New York Times. The total number of monarchs may have risen to 140 million from 35 million a few years ago, according to Alejandro del Mazo, chairman of the National Commission of Natural Protected Areas.

First with the help of a 24-hour body clock, known as circadian clock that lies in their antenna, the butterflies deduce whether it’s 8 in the morning or 4 in the afternoon, This helps them figure out whether the sun should be on the right or left. Once they know that, they follow the angle of the sun, which is captured by special cells called photoreceptors that sit inside their eyes to get to their destination. Scientists have dubbed this surprisingly sophisticated system – time adjusted sun compass.

“We are seeing the beginning of success,” said Daniel Ashe, director of the United States Fish and Wildlife Service, who was in Mexico for the presentation. “Our task now is to continue building on that success.”

What’s contributing to the monarchs’ success? One factor is the re-introduction of milkweed, which monarchs prefer, but has been decimated in many places. Officials are doing this by planting acres of milkweed—more than 250,000 last year, according to Ashe—and by more closely regulating the pesticides that destroy it.

Along with flying creatures like bees and birds, monarch butterflies are pollinators, responsible for fertilizing flower- and fruit-bearing plants throughout the continent. Without pollinators, we don’t have food—one reason why their decline has been so troubling.

According to Pollinator Partnership, roughly 1,000 plants grown for food, beverages, fibers, spices, and medicines worldwide need to be pollinated by animals in order to produce the goods on which we depend. Think apples, blueberries, chocolate, coffee, melons, peaches, potatoes, pumpkins, vanilla, almonds, and tequila. In the United States alone, products pollinated by bees and other insects are worth $40 billion annually.

We certainly have a long way to go in completely rehabilitating the pollinator population in North America, but the news this week about monarchs is definitely a step in the right direction.