Today, finches occupy every continent except Australia, most eating seeds, a diet for which their bills are well-adapted. Over the past several million years, the 13 Galapagos finches have come to occupy the varied Galapagos islands. Finches found on these islands have very different bill shapes and feeding behaviors than finches found on the nearby mainland. Darwin gathered a considerable amount of field data on these finches and their habitats in order to propose his findings. Determining that there were 13 different species of finches, Darwin proposed that they arose by