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Stewart Shag Phalacrocorax chalconotus

Justification
This species is classified as Vulnerable because it has a small range and is restricted to a small and decreasing number of colonies. Although it is known to abandon and reoccupy sites over decades, the loss of a comparatively large number of locations in recent years is of concern, and although population trends are unclear, the population may be declining.

Taxonomic source(s)
del Hoyo, J.; Collar, N. J.; Christie, D. A.; Elliott, A.; Fishpool, L. D. C. 2014. HBW and BirdLife International Illustrated Checklist of the Birds of the World. Barcelona, Spain and Cambridge UK: Lynx Edicions and BirdLife International.
Turbott, E. G. 1990. Checklist of the birds of New Zealand. Ornithological Society of New Zealand, Wellington.

Synonym(s)
Leucocarbo chalconotus Turbott (1990)

Identification
68 cm. Large cormorant with pied and bronze phases. Pied phase, blackish head, upperparts with white patch on upperwings appearing as a bar when folded. White underparts. Pink feet. Orange caruncles. Bronze phase, all brownish-black with green-blue sheen. Voice Male calls at nest, silent away from colonies.

Distribution and population
Phalacrocorax chalconotus is endemic to New Zealand, breeding on the South Island from the coast of North Otago south to Foveaux Strait, and on Stewart Island. In total, it breeds at c.9 localities (G. A. Taylor in litt. 2000), in colonies of 10-500 pairs (Heather and Robertson 1997). Individual island population estimates from the 1950s-1970s indicate a total of c.3,000 birds (Marchant and Higgins 1990). The only national census dates from 1981, and estimated the population at 1,800-2,000 breeding pairs, 900-1,000 in both Otago and Southland. The Otago population doubled to 1,850 pairs in 1987-1988, and the breeding range also expanded, but numbers then decreased to 1,500 pairs in 1992-1993 (Taylor 2000). Total numbers may be as high as 5,000-8,000 (C. Lalas in litt. 1994). In 1914, the population on Kane-te-toe Island was estimated at 400-500 nests; however, by 1975 the colony had been deserted (Watt 1975). The population on Centre Island declined from 600 to 25 nests between 1955 and 1991 (Taylor 2000). Colonies on Jacky Lee and Codfish Islands have also been deserted (B. Weeber in litt. 2000). It disperses over shallow inshore waters within 15 km of land (G. A. Taylor in litt. 2000).

Population justification
Population estimates have varied, although the population may be as high as 5,000-8,000 individuals (C. Lalas in litt. 1994). This is roughly equivalent to 3,300-5,300 mature individuals.

Trend justification
Although there are no new data on the population size, it is suspected to be declining overall, as the colony at Centre Island has declined dramatically (Taylor 2000), and colonies on the islands of Jacky Lee and Codfish have been deserted (B. Weeber in litt. 2000).

Ecology
It breeds on rocky headlands and islands, building a platform nest of twigs, seaweed and guano, 0.5 m in diameter and 1-1.5 m high (Marchant and Higgins 1990, Heather and Robertson 1997). It appears to eventually destroy the surrounding vegetation, probably contributing to the abandonment of colonies until sufficient regeneration has occurred (Watt 1975). It feeds on fish and marine invertebrates (Heather and Robertson 1997).

Threats
Human activities very easily disturb colonies and may have caused the desertion of some in the past (Watt 1975). Illegal shooting is a problem (Heather and Robertson 1997). Set-nets are a major threat, regularly catching birds, particularly near breeding colonies. Introduced predators such as mustelids Mustela spp., cats and rodents are a threat to mainland colonies (Taylor 2000).

Conservation Actions Underway
Although only one national census has been completed, many counts have been made at individual colonies, mostly since the 1950s (Taylor 2000). Conservation Actions Proposed
Survey the species's entire range to locate and census all breeding colonies. Monitor at least one colony in Otago and Foveaux Strait yearly, and census the entire breeding population every 10 years. Develop techniques to establish new colonies. Fence colonies at mainland sites to exclude predators and stock. Develop an advocacy programme to discourage shooting and encourage the safe use of set-nets in order to minimise bycatch, enforcing restrictions if necessary, near Stewart Island colonies (Taylor 2000). Prevent marine farming near breeding colonies and feeding areas (B. Weeber in litt. 2000). Obtain legal protection for all colonies (Taylor 2000).

References
Heather, B. D.; Robertson, H. A. 1997. The field guide to the birds of New Zealand. Oxford University Press, Oxford, UK.

Marchant, S.; Higgins, P. J. 1990. Handbook of Australian, New Zealand and Antarctic birds, 1: ratites to ducks. Oxford University Press, Melbourne.

Taylor, G. A. 2000. Action plan for seabird conservation in New Zealand. Department of Conservation, Wellington.

Watt, J. P. C. 1975. Notes on Whero Island and other roosting and breeding stations of the Stewart Island Shag (Leucocarbo carunculatus chalconotus). Notornis 22: 265-272.

Further web sources of information
Explore HBW Alive for further information on this species

Search for photos and videos, and hear sounds of this species from the Internet Bird Collection

Text account compilers
Benstead, P., Mahood, S., McClellan, R., Pilgrim, J., Taylor, J.

Contributors
Lalas, C., Taylor, G., Weeber, B.

IUCN Red List evaluators
Butchart, S., Symes, A.

Recommended citation
BirdLife International (2014) Species factsheet: Phalacrocorax chalconotus. Downloaded from http://www.birdlife.org on 29/07/2014. Recommended citation for factsheets for more than one species: BirdLife International (2014) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 29/07/2014.

This information is based upon, and updates, the information published in BirdLife International (2000) Threatened birds of the world. Barcelona and Cambridge, UK: Lynx Edicions and BirdLife International, BirdLife International (2004) Threatened birds of the world 2004 CD-ROM and BirdLife International (2008) Threatened birds of the world 2008 CD-ROM. These sources provide the information for species accounts for the birds on the IUCN Red List.

To provide new information to update this factsheet or to correct any errors, please email BirdLife

To contribute to discussions on the evaluation of the IUCN Red List status of Globally Threatened Birds, please visit BirdLife's Globally Threatened Bird Forums.

Additional resources for this species

ARKive species - Stewart Island shag (Phalacrocorax chalconotus) 0

Key facts
Current IUCN Red List category Vulnerable
Family Phalacrocoracidae (Cormorants)
Species name author (Gray, 1845)
Population size 3300-5300 mature individuals
Population trend Decreasing
Distribution size (breeding/resident) 45 km2
Country endemic? Yes
Links to further information
- Additional Information on this species