You are an experienced naturalist and biologist and you observe two birds mating that you do not believe are members of the same species. The eggs from this breeding do not hatch, and when you obtain one of the eggs, you find embryonic development stopped not long after fertilization. Which of the following conclusions is supported by these observations?
A) Pre-zygotic isolation prevented successful reproduction.
B) Post-zygotic factors prevented successful reproduction.
C) Behavioral isolation prevented successful reproduction.
D) Temporal isolation prevented successful reproduction.
E) This is evidence to suggest the two types of birds are a single species.