MEXICO CITY — After years of being ravaged by severe weather and shrinking habitats, the monarch butterflies hibernating in the Mexican mountains rebounded last year, kindling cautious hope that one of the insect world’s most captivating migrations may yet survive.

The World Wildlife Fund said at a news conference here on Friday that the orange-and-black butterflies, which fly more than 2,500 miles each year from Canada and the United States to a cluster of mountain forests in Mexico, covered about 10 acres this winter, an area more than three times as large as the space they covered last year.

“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.”

The butterflies arrive in Mexico starting in October and spend the winter clinging to branches in the forests of Michoacán State and Mexico State.