Purple Crows

Every fall, over one million Purple Crows journey from northern to southern Taiwan. They spend the winter in warm valleys known as "Purple Butterfly Valleys." In the spring, they return north to mate and lay eggs for a new generation. But these butterflies are under threat. In the past 20 years, many of the purple butterfly valleys have disappeared because of human activities. Today, these valleys and the butterflies are protected.

Image credits: main image, © National Museum of Natural Science Taiwan.