Islands often appear to be stable.
In some cases, organisms have persisted for many millions of years, and having an oceanic climate, extreme climatic events may be comparatively rare. Feral pigs have also contributed to habitat destruction which is however predominantly an anthropogenic effect. Rat predation was limiting the population growth of the extant Cahow population. The tropicbirds, which arrive to breed later in the year than the Cahows, would kill any petrel chicks they found and then use the nest site as their own. An additional technique used was to artificially construct nest sites on the vegetated tops of the nesting islets where tropicbirds are less likely to find them.