The cautious comeback of an intrepid insect

A lepidopterologist’s fantasy

LIKE many a sun-seeking tourist, the monarch butterfly prefers to spend winter in the warmth of Mexico. Before the first frosts, it leaves its breeding grounds in Canada and the United States and flies up to 5,000km (3,000 miles) to a patch of forest west of Mexico City. Weighing down tree branches in giant clusters by night, the monarchs flutter through the forest in their millions in the day, turning the sky amber.

This natural wonder faces two threats. In the butterflies’ northern feeding and breeding sites, unpredictable weather is hindering reproduction. A cold summer in Canada and the United States in 2009 meant that the following winter saw fewer monarchs in Mexico than at any time since records began in 1994. Deforestation in the butterflies’ Mexican base, mainly through illegal logging, has made their winter holidaying harder still.

Yet the insect battles on. This winter the butterflies colonised four hectares (ten acres) of Mexican forest, more than double the amount last year. This is still on the low side (1997, the busiest year on record, saw 18 hectares occupied), but Omar Vidal, head of the Mexican office of WWF, an environmental advocacy group, says the news is encouraging.

Illegal logging has almost been eradicated, thanks to the fostering of alternative jobs such as mushroom-growing and tourism, which attracts some 115,000 visitors per year. “People in this region are hard-working…they only need an honourable source of work to bring bread back home,” says Rosendo Caro, director of the butterfly reserve, now a UNESCO world heritage site. Last year less than two hectares of forest were lost to illicit felling, down from 461 in 2006.

Jobs in tourism have been put at risk by a surge in drug-related violence in the state of Michoacán, which caused the number of visitors to fall by almost half this winter. As well as winning back those butterfly-spotters, Mr Caro wants to attract more visitors in the summer, when the monarchs are away and local restaurants and petrol stations see little custom. For once, a stampede of tourists may be just what is needed to preserve a natural marvel.