Simulated environment with equal amounts of insects seeds and fruit which flock will be able to eat the most the least and why

This simulation is based on the experiment to examine the natural selection in birds.

Explanation:

Consider a species of birds A which eats only insects. Likewise, species of birds B and C which eats seeds only and fruits only respectively.

When there is equal amount of insects, seeds and fruits then the flock of all three species will be able to eat equal.

But, consider another species of birds D which eats all three of those foods then this species will be able to eat the most while the species eating the single type of food will end up eating the least.