Reduced Viability in Offspring:
Prior to the Nevis population being moved to St.Kitts, the two separate populations did not have a chance to breed. Their habitats were entirely separate, which previously indicated a type of prezygotic reproductive isolation. Looking at the evidence that is presented, postzygotic reproductive isolation is causing the offspring to die. After observing the reproduction between the two organisms, it appears that any young that are produced are not viable. In most cases, the offspring do not make it to birth and die during embryonic development. The few cases that have survived through the embryonic stage die at birth or minutes after.