Juan Fernández petrels spend most of their life out over the oceans, where they search for fish and squid on which to feed (2). They are often found in areas of upwelling, where cool, nutrient-rich water rises to the surface, resulting in an abundance of prey. They can be seen feeding alongside other seabirds (2), or occasionally around fishing boats (2). The Juan Fernández petrel often depends on sub-surface predators, such as cetaceans and yellowfin tuna, to drive prey to the surface (3).
Juan Fernández petrels return to their isolated island to breed in October to November (2), where they form large breeding colonies. Females lay a single egg in a burrow and the grey, downy chicks hatch in February and March. The chicks are brooded for typically three weeks before being left unattended during the day while their parents go off to feed (2) (5). The adults return by dusk to their burrows and waiting offspring. Most of the petrel chicks fledge in May and June (2).