• Summary
• Text account
• Data table and detailed info
• Distribution map
• Reference and further resources

Justification of Red List category
This species is listed as Endangered because it has a very small population which has declined rapidly, which is predicted to continue given current threats.

Population justification
A total of 434 pairs (roughly equating to 1,300 total individuals) were counted in the third complete census over the 2011-2012 breeding season.

Trend justification
The species's population has declined by 40% over 14 years from 1997 to 2011 (Debski et al. 2012), this would equate to a decline of 61.7% over 3 generations, placed here in the range 50-79%.

Phalacrocorax featherstoni is found in the Chatham Islands, New Zealand, on Chatham, Pitt, Mangere, Little Mangere, South East (= Rangatira), Star Keys, the Pyramid, Big and Middle Sister, Murumurus, the Castle and Rabbit Islands (Marchant and Higgins 1990, Imber 1994, Taylor 2000). The population has been variously estimated at c.500 pairs, fewer than 1,000 pairs (Heather and Robertson 1997) and in 1997-1998, at 729 pairs, following a complete census over the entire breeding range (Bell and Bell 2000). However, new information suggests that the population has declined, with 547 pairs counted in the second complete census over the 2003-2004 breeding season (Bester and Charteris 2005), and 434 pairs estimated in 2011-2012 (Debski et al. 2012).

It nests in small colonies of between one and 44 pairs (Debski et al. 2012), on rocky shores and islets, headlands and cliffs. Breeding distribution is limited by suitable nesting sites (Marchant and Higgins 1990). It feeds primarily on small fish, supplemented by marine invertebrates (Heather and Robertson 1997). The species shows foraging area fidelity and may forage up to 18 km away from breeding colonies, with the mean distance of 5.2 km (Bell 2015). Individuals forage in shallow water, with mean dive depth of 6.6 m (max 24.4 m, but with 90% of all dives being <13 m deep) (Bell 2015). Mean dive duration has been estimated at 22 seconds (max 69 seconds), with a mean rest period of 19 seconds (Bell 2015).

The effects of introduced species on Chatham and Pitt Islands are not known, with birds tending to nest in inaccessible sites. Some nests, however, could be affected by Feral Cats Felis catus, Black Rats Rattus rattus, Brown Rats R. norvegicus, Common Brushtail Possum Trichosurus vulpecula and Weka Gallirallus australis (Taylor 2000, Bell 2015). Birds are sometimes illegally shot by fishermen (Heather and Robertson 1997, Taylor 2000). A total of 40-80 birds may be caught in crayfish pots annually (Bell and Bell 2000), but changes to fishing practice may have reduced bycatch (Bell 2012). Recent declines could be a response to changes in the marine environment that are affecting food supplies (Bester and Charteris 2005). The species is potentially threatened by climate change because of its geographically bounded distribution to islands with a maximum altitude of 283 m (Birdlife International unpublished data).

Conservation Actions Underway
In 1961, sheep and cattle were removed from South East Island and, in 1968, sheep were taken off Mangere Island (Taylor 2000).

Conservation Actions Proposed
Census the entire adult population once a suitable methodology has been developed, and at 10-year intervals thereafter, and monitor two accessible colonies annually to determine trends (Taylor 2000). Assess the impact of rock lobster fishing practices (B. Weeber in litt. 2000). Remove feral cats and G. australis from Pitt Island if agreement is reached with residents, and remove sheep, cattle and pigs from parts of Pitt and Chatham Islands that are suitable for colonies. Fence colonies (with owners' permission) if stock are found to be impacting on colonies (Taylor 2000). Conduct further research into the breeding biology and foraging ecology of the species (Bell 2015, I. Debinski in litt. 2016).

63 cm. Medium-sized, slight grey-and-black cormorant. Breeding, black head, rump, tail, thighs. Dark grey upperparts with small black spots over wings, back. Grey underparts. Apple-green facial skin. Double crest on head. Non-breeding, no crest. Yellow facial skin. Paler underparts. Voice Displaying male noisy, female silent.

Text account compilers
Taylor, J., Westrip, J., Benstead, P., Harding, M., Mahood, S., Martin, R., Fjagesund, T., McClellan, R., Miller, E., Pilgrim, J.

Contributors
Weeber, B., Bester, A., Hitchmough, R., Bell, B., Debski, I., Bell, B.

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Recommended citation
BirdLife International (2024) Species factsheet: Pitt Island Shag Phalacrocorax featherstoni. Downloaded from https://datazone.birdlife.org/species/factsheet/pitt-island-shag-phalacrocorax-featherstoni on 23/12/2024.
Recommended citation for factsheets for more than one species: BirdLife International (2024) IUCN Red List for birds. Downloaded from https://datazone.birdlife.org/species/search on 23/12/2024.