The nests are little more than scooped-out areas with grass built up to circle the depression. But they also feature a critical moat dug by the birds to keep away water from the often torrential rains. Incubation takes about two months, and the males and females share nest duties, allowing one to feed at sea while the other protects the egg. When a partner returns, it pushes the other from the nest, dips its head to the egg and utters eh eh . After the chicks hatch, the parents feed them a nutrient-rich diet of regurgitated fish, squid and oil.
Chicks stimulate feeding by touching the parent's bill.
For juveniles, this is the time to snag a mate of one's own, or at least to practice courting. Aside from occasional squabbles, the islands are filled with a cacophony of vocalizations that accompany the ritualistic courting dances. The noise begins just before dawn and continues into the night. New human arrivals, unaccustomed to the volume level, complain of being kept awake by juvenile revelers until the wee hours. In addition to using calls, the birds communicate with their bills.