Phalacrocorax colensoi

Taxonomy

Assessment Information

Geographic Range

Population

Habitat and Ecology

Threats

Conservation Actions

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Taxonomy [top]

Kingdom	Phylum	Class	Order	Family
ANIMALIA	CHORDATA	AVES	PELECANIFORMES	PHALACROCORACIDAE

Scientific Name:

Phalacrocorax colensoi

Species Authority:

Buller, 1888

Common Name/s:

English

–

Auckland Island Shag, Auckland Islands Shag

Assessment Information [top]

Red List Category & Criteria:

Vulnerable D2 ver 3.1

Year Published:

2010

Assessor/s:

BirdLife International

Reviewer/s:

Calvert, R., Butchart, S., Bird, J.

Contributor/s:

Bell, B., Weeber, B., Taylor, G.

Justification:
This species is classified as Vulnerable because it has a very small range when breeding, being locally restricted to inaccessible coastline sites, and is therefore susceptible to stochastic effects and human impacts. Population trends are unknown, but are assumed to be stable.

History:

2008	–	Vulnerable
2005	–	Vulnerable
2004	–	Vulnerable
2000	–	Vulnerable
1996	–	Vulnerable
1994	–	Vulnerable

Geographic Range [top]

Range Description:	Phalacrocorax colensoi is restricted to the Auckland Islands and adjacent waters, New Zealand. Colonies are present on Auckland, Enderby, Rose, Ewing and Adams Islands. The total breeding population has been estimated at less than 1,000 pairs⁴. Surveys in 1988 and 1989 indicated 475 nests in 11 colonies on Enderby, one colony of 62 nests on Rose, and 306 nests on Ewing⁵. Feeding range is assumed to be 24 km (cf. New Zealand King Shag P. carunculatus).
Countries:	Native: New Zealand; United States
Range Map:	Click here to open the map viewer and explore range.

Population [top]

Population:	Although the population was thought to be less than 1,000 individuals (Robertson and Bell 1984), surveys in 1988 and 1989 indicated 475 nests in 11 colonies on Enderby, one colony of 62 nests on Rose, and 306 nests on Ewing (Taylor 2000). Based on these data, a population of 1,000-2,499 mature individuals is estimated, although a more up-to-date population estimate is needed.
Population Trend:	Stable

Habitat and Ecology [top]

Habitat and Ecology:	It nests on the ground on ledges and the tops of steep cliffs. Sites are abandoned when sheltering plants are killed by guano, and waves sometimes destroy nests³. It feeds on small fish and marine invertebrates².
Systems:	Terrestrial; Marine

Threats [top]

Major Threat(s):	On Auckland Island, the major threat is from feral pigs which destroy any colony they can reach and, as a consequence, most, if not all, colonies are in inaccessible places¹. On Rose and Enderby, feral cattle and rabbits may have had a similar impact and, on Enderby, cattle eliminated a tussock species that was a favoured nesting material⁵. Cats are also potential predators on Auckland Island^5,6.

Major Threat(s):

On Auckland Island, the major threat is from feral pigs which destroy any colony they can reach and, as a consequence, most, if not all, colonies are in inaccessible places¹. On Rose and Enderby, feral cattle and rabbits may have had a similar impact and, on Enderby, cattle eliminated a tussock species that was a favoured nesting material⁵. Cats are also potential predators on Auckland Island^5,6.

Conservation Actions [top]

Conservation Actions:	Conservation Actions Underway In 1995, feral goats were eradicated from Auckland Island and, in 1993, feral cattle and rabbits were removed from Enderby and Rose⁵. In 1998, the Auckland Islands group (already a nature reserve) was declared part of a World Heritage Site. In 2003 the area was designated as a Marine Reserve⁷. Conservation Actions Proposed Census entire adult population once a suitable methodology has been developed. On Auckland Island, survey coastline to locate all nesting sites. On Enderby, monitor breeding population every 10 years. On Auckland Island, eradicate feral cats and pigs⁵.

Conservation Actions:

Conservation Actions Underway
In 1995, feral goats were eradicated from Auckland Island and, in 1993, feral cattle and rabbits were removed from Enderby and Rose⁵. In 1998, the Auckland Islands group (already a nature reserve) was declared part of a World Heritage Site. In 2003 the area was designated as a Marine Reserve⁷.

Conservation Actions Proposed
Census entire adult population once a suitable methodology has been developed. On Auckland Island, survey coastline to locate all nesting sites. On Enderby, monitor breeding population every 10 years. On Auckland Island, eradicate feral cats and pigs⁵.

Citation:	BirdLife International 2010. Phalacrocorax colensoi. In: IUCN 2011. IUCN Red List of Threatened Species. Version 2011.2. <www.iucnredlist.org>. Downloaded on 22 May 2012.
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