During migration they feed whenever food is available. It is possible that krill abundance determines the migration of the species, allowing them to exploit the high concentrations of krill which occur each summer at both polar regions. In places, pigs, cattle and sheep have destroyed whole colonies. Soil erosion after fire can destroy suitable sites for burrowing. Birds also ingest small plastic particles while at sea which may limit the birds ability to maintain condition and contribute to deaths during migration.
Feral cats are also a problem, as they find shearwater chicks easy prey.
Trampling of burrows by humans can also cause their death. Similarly, erosion caused by recreational vehicles can destroy suitable sites for burrowing. It is important to keep off colonies. Natural mortality occurs mainly during the first migration due to exhaustion and starvation. The average lifespan is 15-19 years but birds can live up to 38 years.