Adaptation
The color of the bill is the same in all of the species of
finches and this has led scientists to the conclusion that they have
all evolved from a single common ancestor. The finches ready to
breed have pure black beaks, and the premature finches have a
somewhat yellow beak.
Each species of finch has adapted to the food available to them. They each have a different size and shape of beak.
Finches
adapt to their surroundings. When a finch is in an environment where
food is easily accessible their beak is more similar to that of the
ancestor finch from the mainland of South America. Finches who eat
seeds normally have a bigger beak to break the seeds open. The
bigger the seed the bigger the beak.
Vampire Finches evolved from Sharp-Beaked Ground Finches. During dry periods, there were not enough seeds to feed on and the finches needed a new source of water for survival. Originally the finches would peck on the Blue-Footed Boobies to remove parasites that lived on their bodies. The vampire finches have very sharp beaks and peck on the Boobies until they drew blood. This does not hurt the Boobies, and they allow it because they are accustomed to having the parasites removed.
This
tree shows the difference in all of Darwin's finches. The difference
in beak size and shape determines what the finch will eat.
To learn more about the other species of finches that live on the
Galapagos Islands click
here.
Continue to Nutrition