Assuming that all the traits contributing to the results below are genetically controlled, which member of a population of Mytai lisgorgeous is most evolutionarily fit?  One that

The member of the Mytai Lisgrogeous population which is most evolutionarily fit is the one which has the successes rate at reproduction.

Evolutionary fitness has been defined by evolutionary biologists as the ability to successfully adapt and reproduce regardless of the environment.

Explanation:

In the case of the Mytai Lisgorgeous, which is a species of bird found in the Amazon Forest, the males come in two variants:

The argument/question is based on observable phenomena which reveal that, while on one hand, the more colourful ones are more prone to predation than the other group with less plumage, on the other, the birds will a drab colour are less successful at reproduction as the female species of the birds prefer the brightly hued males.

So the logic behind the definition of fitness here is this, it holds no biological value if the members of a species have evolved to the point where they are no longer prone to predation if they cannot reproduce.

Cheers!