Behaviour Breeding is biennial if a chick is successfully reared. Birds return to colonies in October and eggs are laid from late November to late December. Chicks hatch from early February to early March, and fledge in early October to early December. Age of first return to colonies is at least 5 years and the age of first breeding is thought to be around 6-12 years old (ACAP 2009).
Habitat Breeding It nests on tussock grassland slopes, ridges, and plateaus (Marchant and Higgins 1990, Heather and Robertson 1997). 
Diet It feeds primarily on squid and fish, supplemented by salps, crustacea and carrion (Imber 1999). 
Foraging range  During incubation, breeding birds from Campbell Island foraged mostly within 1,250 km of the colonies over shallow (<1500 m deep) shelf and shelf break waters of the Campbell Plateau north to southern New Zealand and over the Chatham Rise, commuting directly to locally productive sites (ACAP 2009).

Diomedea epomophora breeds on Campbell Island (99% of the total population), on Adams, Enderby and Auckland Islands (Auckland Islands group), and on Taiaroa Head (Otago Peninsula, South Island), New Zealand. The Campbell population was estimated at 7,800 breeding pairs in 2004-2008 (ACAP 2009). Sixty nine pairs were present on Enderby in 2001 (Childerhouse et al. 2003), and 54 and 63 nesting pairs were estimated from aerial surveys in 2013 and 2014, respectively (Baker and Jensz 2013, Baker et al. 2014). Although c.20 pairs have previously been reported to breed on Auckland and Adams Islands combined (Croxall and Gales 1998), aerial surveys during the last 10 years appear to confirm that there are presently no breeding pairs on Auckland Island (B. Baker pers. comm. 2016). No pure-bred D. epomophora are present at Taiaroa Head (Heather and Robertson 1997, Taylor 2000). The species circumnavigates the Southern Ocean after breeding (Croxall and Gales 1998), but is most commonly recorded in New Zealand and South American waters (Marchant and Higgins 1990). Breeding adults forage from the South Island southwards to the Campbell Plateau (Waugh et al. 2002) and north to the Chatham Rise. Non-breeding birds forage on the west and east coast of South America (Moore and Bettany 2005), generally between 30-55°S (ACAP 2009). Whole island censuses on Campbell Island in 1994-1995 and study plot censuses in 1996-1997 indicate that the population is likely to be stable, or possibly increasing (Moore et al. 1997).

Conservation Actions Underway
CMS Appendix II and ACAP Annex 1. Cattle and sheep have been removed from Campbell, and cattle, rabbits and mice have been eradicated from Enderby. Rats were eradicated from Campbell in 2001, and an expedition in 1993 found no evidence of them persisting (P. Moore in litt. 2003). Almost 36,000 birds have been banded on Campbell since the 1940s, but since 2006 bands are being removed, except in two study colonies. Two study areas on Campbell were monitored annually in the 1990s (P. Moore in litt. 2003). All islands are nature reserves and, in 1998, were declared a World Heritage Site.

Conservation Actions Proposed
Census the Campbell at 10-year intervals. Monitor vegetation change on Campbell and Enderby and assess its effect on habitat availability. Eradicate pigs and cats from Auckland Island (Taylor 2000). Check for leg bands during censuses for data on survival and recruitment. Develop mitigation devices/techniques to minimise fisheries bycatch.