Answer:
Coevolution
Explanation:
Coevolution refers to the process of reciprocal adaptation of two or more species due to their close interaction for a longer period of time. It is a mutual adaptation between those species to reduce harmful effects of competition. Coevolution occurs by development of certain morphological and behavioral features in each of the species. By living in different areas, warbler species reduce the competition between them and thus, are an example of coevolution.