Darwin's Finches shows adaptive radiation, which occurred in response to various food resources available. They feed on insects, tree buds, seeds, cactus, etc. Carrion are dead bodies and no finches feed on them. Related Theory Darwin studied the climatic conditions, fauna and flora of Galapagos islands. He noticed varieties of small birds in these islands which differed mainly in the shape and size of their beak and in the colour of their plumage. These birds are now called Darwin's finches. Darwin concluded that the American mainland species was the original one from which different forms migrated to the different islands of Galapagos and adapted to the different environmental conditions of these islands. These adapted forms are considered to be the new species. Thus, Darwin's finches provide a beautiful example of adaptive radiation supporting the concept of evolution.