Answer: The correct answer is -
Genetic diversity.
Step-by-step explanation:
Genetic diversity can be described as the number of genetic traits or characteristics that are present in the genome (genetic makeup) of a particular species. It enables the population of the species to adapt to changing environmental conditions.
Genetic characteristics vary within a population due to presence of different gene variants, also called alleles.
As per the given information in the question, in one species of bird, there are three varieties of feather color. Thus, it indicates genetic diversity within that species of bird.