Haematopus chathamensis

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	CHARADRIIFORMES	HAEMATOPODIDAE

Scientific Name:

Haematopus chathamensis

Species Authority:

Hartert, 1927

Common Name/s:

English

–

Chatham Island Pied Oystercatcher, Chatham Islands Oystercatcher, Chatham Oystercatcher

Assessment Information [top]

Red List Category & Criteria:

Endangered D ver 3.1

Year Published:

2008

Assessor/s:

BirdLife International

Reviewer/s:

Mahood, S., Butchart, S.

Contributor/s:

Schmechel, F., Aikman, H., Taylor, G., Bell, B., Sawyer, S.

Justification:
This species is listed as Endangered because it has an extremely small population. It has significantly increased over the last 20 years, probably owing to intensive conservation efforts⁶. However, even on islands free from mammalian predators, population sizes fluctuate, with numbers on one island undergoing a possible long-term decline.

History:

2006	–	Endangered
2004	–	Endangered
2000	–	Endangered
1994	–	Endangered

Geographic Range [top]

Range Description:	Haematopus chathamensis is endemic to the Chatham Islands, New Zealand. In 1987-1988, the population was estimated at 100-110 birds, including 44 breeding pairs: eight on South East Island (= Rangatira); 25 on Chatham Island; nine on Pitt Island; and two on Mangere Island. In 1998, a census indicated 140-150 birds, representing a significant increase. Numbers on South East, however, appear to have gradually declined since the 1970s⁶. Very small numbers may breed on Star Keys⁴. In 2004, a minimum of 266 birds were counted on most of the coast of four islands in the Chathams group, representing a population of 310-325 birds⁹.
Countries:	Native: New Zealand
Range Map:	Click here to open the map viewer and explore range.

Population [top]

Population:	In 2004, a minimum of 266 birds were counted on most of the coast of four islands in the Chathams group, represented a population of 310-325 birds (Moore 2005). However, the number of mature individuals in breeding pairs remains below 250.
Population Trend:	Increasing

Habitat and Ecology [top]

Habitat and Ecology:	It builds nests in scrapes on sandy and rocky shores, away from the waterline. Occasionally, it breeds amongst low vegetation or constructs nests out of vegetation⁷. It lays two to three eggs⁴. It starts breeding from three years old and most paris attempt breeding each season (98%); productivity averages 0.44 fledglings/season/pair¹⁰. Mean life expectancy is 7.7 years. The oldest recorded bird lived for a minimum of 28 years⁷. It feeds principally on molluscs and marine worms, also taking other invertebrates⁴.
Systems:	Terrestrial; Marine

Habitat and Ecology:

It builds nests in scrapes on sandy and rocky shores, away from the waterline. Occasionally, it breeds amongst low vegetation or constructs nests out of vegetation⁷. It lays two to three eggs⁴. It starts breeding from three years old and most paris attempt breeding each season (98%); productivity averages 0.44 fledglings/season/pair¹⁰. Mean life expectancy is 7.7 years. The oldest recorded bird lived for a minimum of 28 years⁷. It feeds principally on molluscs and marine worms, also taking other invertebrates⁴.

Systems:

Terrestrial; Marine

Threats [top]

Major Threat(s):	Introduced predators are a major threat on Pitt and Chatham, as are cattle and sheep^3,7. South East and Mangere are free of mammalian predators, but population sizes are still highly variable, and the reason for the decline on South East is unknown⁶. However, video camaras set by nests have revealed that feral cats are a major nest predator⁹. Predation by native birds, especially Weka Gallirallus australis, may be a potential threat⁷. On Chatham, some pairs are forced to nest close to the tideline because introduced marram grass has spread and reduced the open areas it prefers - these nests are more vulnerable to high tides and storms - flooding is the major cause of egg loss^2,5,10. Disturbance and trampling of nests by stock and vehicles may affect breeding success⁸.

Major Threat(s):

Introduced predators are a major threat on Pitt and Chatham, as are cattle and sheep^3,7. South East and Mangere are free of mammalian predators, but population sizes are still highly variable, and the reason for the decline on South East is unknown⁶. However, video camaras set by nests have revealed that feral cats are a major nest predator⁹. Predation by native birds, especially Weka Gallirallus australis, may be a potential threat⁷. On Chatham, some pairs are forced to nest close to the tideline because introduced marram grass has spread and reduced the open areas it prefers - these nests are more vulnerable to high tides and storms - flooding is the major cause of egg loss^2,5,10. Disturbance and trampling of nests by stock and vehicles may affect breeding success⁸.

Conservation Actions [top]

Conservation Actions:	Conservation Actions Underway Nest manipulation may have helped to increase hatching success on Chatham. Nests are moved slowly back up the beach to reduce flooding. Artificial incubation was trialled but did not increase overall productivity. Stock have been fenced from some beaches on Chatham, signs have been erected to reduce human and dog disturbance, and marram is being controlled in some areas. Recently, intensive predator control combined with nest manipulation resulted in a high number of fledglings. A research programme aiming to assess the effects of predators, flooding and management on breeding success has been initiated^1,7. Conservation Actions Proposed Increase predator control at selected sites. Continue habitat management. Continue nest manipulation. Continue research on population dynamics.

Conservation Actions:

Conservation Actions Underway
Nest manipulation may have helped to increase hatching success on Chatham. Nests are moved slowly back up the beach to reduce flooding. Artificial incubation was trialled but did not increase overall productivity. Stock have been fenced from some beaches on Chatham, signs have been erected to reduce human and dog disturbance, and marram is being controlled in some areas. Recently, intensive predator control combined with nest manipulation resulted in a high number of fledglings. A research programme aiming to assess the effects of predators, flooding and management on breeding success has been initiated^1,7.

Conservation Actions Proposed
Increase predator control at selected sites. Continue habitat management. Continue nest manipulation. Continue research on population dynamics.

Citation:	BirdLife International 2008. Haematopus chathamensis. In: IUCN 2011. IUCN Red List of Threatened Species. Version 2011.2. <www.iucnredlist.org>. Downloaded on 21 May 2012.
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