The Galapagos Penguin nests on average twice a year with two eggs per clutch (Vargas et al. 2007). They nest in cracks, crevices or other depressions in the lava rocks along the shore and lay large white eggs (Bailey 1962). The Galapagos Penguin also dig burrows when possible. Most birds decorate their nest with small objects such as leaves and twigs, which may serve primarily as decoration (Boersma 1976).
Cool water is believed to be an environmental cue for breeding in the Galapagos Penguin, and if water temperatures rise above 25º C, breeding will not occur. When water temperatures rise during El Niño events, nests are deserted as penguins are forced to travel farther to find food (Boersma 1978).
Chicks begin peeping within the egg a day before hatching which can take anywhere from fifteen minutes to eight hours. The laid first will also hatch first, followed several days after by the second egg. The parents remain at the nest site until the chicks are approximately three weeks old in order to protect them from predators such as the Sally lightfoot crab, rice rats and Galápagos snakes (Boersma 1976).
Chicks can be fully grown within two months, but growth is dependent on food availability (Boersma 2008). Chicks receive on average twenty small fish a day from their parents, when plenty of fish are available (Boersma 1976). Therefore, when there are particularly strong upwellings, chicks will grow most quickly. The cold upwellings prior to a warm El Niño season are especially productive and chicks will grow quite quickly when this occurs (Boersma 1978).