Monarch butterflies descend on Mexican forest during annual migration.
ANGANGUEO, MICHOACAN, MEXICO (NOVEMBER 28, 2015) (REUTERS) – Thousands of striking orange and black monarch butterflies began arriving to their winter home in central Mexico on Saturday (November 28) in their annual migration.
The 3,000-mile (4,800-km) mass migration of monarch butterflies in North America is one of the insect world’s fantastic feats, with millions embarking on the arduous journey from as far north as Canada down into Mexico and the California coast each autumn.
The number of migrating monarchs has plummeted in recent years. Experts said while an estimated one billion monarch butterflies migrated to Mexico in 1996, that number stood at about 35 million last year.
Threats to them include habitat loss due to human activities, pesticides and climate change, experts say.
Scientists at the Ecosystems Research Centre (CIECO) at the National Autonomous University of Mexico (UNAM) in Morelia, in recent years developed an organic fertilizer that is being spread throughout Mexico’s forests to protect the butterflies.
The National Commission for Protected Natural Areas (CONANP) has also stepped up monitoring across woodland areas near the U.S. border.
Francisco Martinez works at Michoacan’s Sierra Chincua sanctuary where the butterflies winter.
“This is a pilgrimage. They come from Canada. They cross 5,000 kilometres from Canada to here. So we are taking care of them so that this continues. We keep protecting their areas that they have here in the Sierra Chincua,” he said.
The butterflies draw visitors from all over the world.
Paul Owen came from Australia to watch the migration.
“I think Canada, where they lay their eggs, and the United States where they fly through and Mexico – the entire system is important for the butterflies and I think that everyone recognizes how important the butterflies are and they protect each of the areas where the butterflies come. it’s very beautiful,” he said.
“It is our responsibility to take care of these kinds of places – this reserve. There are very such places in the world – two or three maybe – and it’s amazing to see these butterflies arrive,” said sanctuary visitor Veronica Mendoza, who lives in Mexico.
Population losses suffered by the charismatic butterfly stem from destruction of milkweed plants they depend on to lay their eggs and nourish hatching larvae. The plant’s decline is tied to factors such as increased cultivation of crops genetically engineered to withstand herbicides that kill native vegetation like milkweed, conservationists say.
Experts hope conservation measures will secure yearly population numbers of more than 225 million of the Monarch butterflies to Mexico.
At Sierra Chincua sanctuary, visitors have been restricted from entering certain areas to not disturb the winged creature.
Adult monarch butterflies boast wings that are orange with black veins and white spots along the outside edges. Their wingspan is about 4 inches (10 cm) and their bodies are black.
While mainly a North American species, monarch populations also can be found in Central America, South America and elsewhere. Those outside North America do not migrate.