Wild-type males are more colorful ... and today they are found all over the world. However, they are banned in states like California because escaped birds can form wild populations.

The struggle is mainly about food -- different types of seeds ... Seeds of all kinds were scarce. The small, soft ones were quickly exhausted by the birds, leaving mainly large, tough seeds ...

All of them evolved from one ancestral species ... years trying to understand the process that had created so many types of finches that differed mainly in the size and shape of their beaks.