Once a year the cloud forest pine trees in the mountains of central Mexico take on spectacular raiment as they play host to millions of over-wintering monarch butterflies. Upon encountering the sea of orange and black wings that dress each tree form top to bottom, it is easy to understand why the Aztecs believed the monarchs were reincarnated warriors, resplendent in their battle colours.

In fact, the life cycle of these butterflies is almost as fantastic, if only because they exhibit migratory behaviour that is unparalleled in the insect world. When the weather begins to improve, the adult monarchs begin to fly north. As they migrate, they stop to lay eggs on milkweed plants.

However the butterflies manage to make the journey, it is certain that they are under severe threat from loss of habitat. The very trait that makes the butterfly trees one of the most beautiful of natural sights makes them especially vulnerable to the activities of illegal loggers.