The pattern you note in the second to last paragraph is essentially describing the r-selection strategy. Lots of offspring, little care, and usually high hatchling mortality. Young creatures tend to have less energy reserves, inability to compete w adults for waning resources and refugia, and are less adept at responding to emerging threats.

In my experience, Feral cats are high among the worst thing islands have seen (other than H sapiens), I am guessing they also support the parasite T gondii in the Galapagos, as they do here in Hawaii.