The 14 species of finch, unique to the Galápagos Islands, that Charles Darwin studied during his journey on HMS Beagle. Each is adapted to exploit a different food source. They are not found on the mainland because competition there for these food sources from other birds is fiercer. Darwin believed all the Galápagos finches to be descendants of a few that strayed from the mainland, and this provided important evidence for his theory of evolution. See also adaptive radiation; character displacement.