Around October each year, millions of monarch butterflies leave their summer breeding grounds in North-Eastern USA and Canada and travel up to 5,000 kilometres to reach the South-Western part of Mexico. The butterflies arrive at their roosting sites in November. They roost in trees during the winter months. Around March, after laying eggs, the adult butterflies die and the northward migration is continued by their offspring. As the monarch butterflies wait for the temperature to rise, they huddle together to keep warm. Once it gets warmer the butterflies take flight. The monarch butterfly migration is a miracle of the natural world. Monarchs know the correct direction to migrate even though the individuals that migrate have never made the journey before. They use the sun to stay on course, but they also have an internal compass that points them in the right direction. A drone disguised as a hummingbird has made it possible to get close to resting monarch butterflies. It has been designed in such a way that it cannot harm or hurt the butterflies in any way. Also, hummingbirds are not a threat to monarch butterflies and so they do not react to the drone. Watch the video below to see just how magical nature is.