Question

how are these birds different species
a new species of finch emerged from the population of finches in your simulation. as you may recall, a new species is one that cannot mate or produce fertile offspring with the current population.
the finches with large beaks on your island have, over time, developed a new mating call that is unrecognizable to the original population. this can prevent mating and reproduction. therefore, these two finches would be different species. this process of one species splitting into two is called speciation.
which criteria for speciation do the finches on your island need to meet to be classified as a different species?
they are not physically able to mate with each other.
they are not attracted to each other ie. they choose to not mate with each other.
produce sterile (infertile) offspring with the original population.
they can mate but their babies do not survive.

Explanation:

A species is defined as a group of organisms that can inter - breed and produce fertile offspring. When a new species emerges, it cannot mate or produce fertile offspring with the original population. In the case of the finches, the new mating call of the finches with large beaks makes them not attracted to the original population, preventing mating and reproduction. This is a form of reproductive isolation.

Answer:

They are not attracted to each other i.e. they choose to not mate with each other.