Monarch butterflies fly south for winter

Thousands of striking orange and black monarch butterflies began arriving to their winter home in central Mexico on Saturday in their annual migration.

The 3,000-mile migration of monarch butterflies in North America is one of the insect world's fantastic feats, with millions making the journey from as far north as Canada down into Mexico and the California coast each autumn.

There are concerns that threats to their habitat is causing a drop in their numbers.

However, experts hope more than 225 million monarch butterflies will continue to arrive in Mexico each year to enjoy the warm weather.