Question

A species of bird was well established on an island. Its beak was well-structured for cracking large nuts. After a few years, some larger birds arrived from a neighboring island. These larger birds drove away the smaller native birds and ate all the large nuts, ignoring the other varieties of nuts. Over a period of time, the native birds seemed to have developed smaller beaks than before. Explain the most likely reason for the change in these birds.

Answer 1

The birds adapted to the changes. Since the large nuts were no longer as abundant because of the large birds, the small birds were left with the smaller nuts. Their larger beaks lost their use since the small nuts did not require such well-structured beaks, so the birds started to develop smaller beaks.