Mexican butterflies not out of the woods

Monarch butterfly colonies in Mexico more than doubled in size this winter after bad storms devastated their numbers a year ago according to conservationists.

Countless butterflies make a fabled 2,000-mile journey each year from Canada, to warmer weather in central Mexico, but the size of that migration can vary wildly.

Researchers recorded fewer of the orange and black insects arriving in Mexico last year than ever before - but the butterfly colonies increase by 109 per cent this year, to cover roughly 10 acres of forest.

Omar Vidal, director of the Mexico branch of the World Wildlife Fund said: "During the previous season, we had the smallest amount of forest covered by the butterflies in 17 years. So I think this is good news and we are seeing the forest covered by butterflies doubled this year."

But while the Monarch colonies rebounded this winter, it is still the fourth thinnest year for the butterfly since researchers started census-taking in 1993.

Illegal loggers have picked away roughly three per cent of a 138,000 acre reserve since it was created in 2000, but officials say they now have that illicit harvest under control.

Severe winter weather linked to climate change is more of a long-term threat but conservationists are optimistic butterflies will be able to cope in the long term if their natural habitat is protected.