Take a close look at your favorite birds and you’ll notice how their differences make them unique and identifiable. Observing a bird’s size, shape, feather coloration, and vocalizations can help with its identification, but you may need to study its beak to learn more about what it eats and the environmental niche it occupies.
Darwin was famous for observing beak differences among birds he encountered on the Galapagos Islands. Known today as Darwin’s finches (a misnomer - they are tanagers), they evolved from a common ancestor via adaptive radiation to take advantage of different food sources on the island. Birds with large beaks (e.g., G. magnirostris) specialize in cracking large seeds and nuts, while those with more delicate beaks (e.g., C. olivasea) feed mainly on insects.
Work done in the 1970s revealed that birds were still evolving quickly in the Galapagos. Natural selection resulting from a severe drought meant that large-beaked, seed-eating birds were better able to survive and pass on their good genes to offspring. Scientists today are looking at the development and underlying molecular basis of beak diversity.