Green turtles and hawksbill turtles are in the coastal waters where nestling also takes place. Both sexes continue to add material to the nest during the incubation and nestling periods. Most avian brood parasites have very short egg incubation periods and rapid nestling growth. Some nests are lost to predators, but an important factor causing nestling mortality is starvation. In the forests of Kerala they were observed preying on nestling and eggs of pigeons. Coral snakes feed mostly on smaller snakes, lizards, frogs, nestling birds, small rodents, etc. Wolverines were observed to prey on nestling golden eagles in Denali National Park. Often the youngest nestling dies from starvation, especially in broods of three or more. Rats have a big impact on nestlings, accounting for 55% of nestling losses. Turtle fossils of hatchling and nestling size have been documented in the scientific literature. Black kites in Spain prey on nestling waterfowl especially during summer to feed their young. Red imported fire ants are another known predator of nestling crested caracaras. The weight of the nestling can triple within five days after hatching. Upon hatching, the nestling (or squab) was blind and sparsely covered with yellow, hairlike down. The growth of nestling tree swallows is influenced by their environment.