[citation needed] The Macquarie shag has largely black upperparts and white underparts.

[4] The birds are present all year round at Macquarie Island, where they breed annually in small to large colonies on bare rocky shores and stacks.

[5] The birds forage locally in shallow coastal waters,[2] with the diet consisting primarily of benthic fish.

[6] A later (October 2003) survey found 472 nesting pairs in eleven colonies on Macquarie Island itself, indicating a 30% decline.

[7] The taxon is listed as Vulnerable under Australia's Environment Protection and Biodiversity Conservation Act 1999,[2] because the population is small, localised and subject to fluctuations in breeding success due to weather conditions and food availability.