The Cape Petrel is marine and pelagic, especially in winter. It occurs mainly over cold waters beyond the continental shelf, but can be found over inshore waters during breeding. Its diet comprises mainly of krill, but also fish, squid, offal, carrion and refuse from ships, acquiring food by hydroplaning, dipping whilst on the wing and occasionally diving. It has been seen associated with whales and other seabirds, and congregates in large flocks around trawlers. The breeding season starts in November with colonies or variable sizes being formed on cliffs or steep rocky slopes. It nests in shallow crevices, in scrape on rocky ledges, on stable beds of gravel or among boulders (del Hoyo et al. 1992).

During breeding season, Cape Petrels feed around Antarctica's shelf and during the winter they range further north, as far as Angola and the Galápagos Islands, Ecuador. They breed on many islands of Antarctica and the sub-Antarctic islands, some going as far as the Auckland Islands, the Chatham Islands, Campbell Island (New Zealand). Their main breeding grounds were on the Antarctic Peninsula, South Georgia (Georgias del Sur), the Balleny Islands, the Kerguelen Islands (French Southern Territory), as well as islands in the Scotia Sea (del Hoyo et al. 1992).