Diomedea dabbenena

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	PROCELLARIIFORMES	DIOMEDEIDAE

Scientific Name:

Diomedea dabbenena

Species Authority:

Mathews, 1929

Common Name/s:

English

–

Tristan Albatross

Assessment Information [top]

Red List Category & Criteria:

Critically Endangered A4ade ver 3.1

Year Published:

2010

Assessor/s:

BirdLife International

Reviewer/s:

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

Contributor/s:

Cooper, J., Cuthbert, R., Wanless, R., Croxall, J., Hilton, G., Ryan, P.

Justification:
This species qualifies as Critically Endangered owing to its extremely small breeding range and a projected extremely rapid population decline over three generations (70 years). Modelled population declines are a consequence of very low adult survival owing to incidental mortality in longline fisheries, compounded by low fledging success caused by predation of chicks by introduced mice.

History:

2009	–	Critically Endangered
2008	–	Critically Endangered
2007	–	Endangered
2005	–	Endangered
2004	–	Endangered
2003	–	Endangered
2000	–	Endangered
1994	–	Not Recognized
1988	–	Not Recognized

Geographic Range [top]

Range Description:	Diomedea dabbenena breeding populations are essentially restricted to Gough Island, Tristan da Cunha, St Helena (to UK), having become extinct on Tristan (although birds were seen prospecting in 1999¹⁴), and in some years one pair breeds on Inaccessible Island^15,20. Using consecutive annual accounts of incubating adults and a population model the population has been estimated at 2,700 breeding pairs, giving a total global population of 11,300 individuals²⁴. Recent counts suggest that the population on Gough has decreased by 28% over 46 years, whereas population modelling predicts annual decline rates of 2.9-5.3%^14,24. Predation of chicks by mice has led to very low fledging success; during the last seven years it has averaged 32.4%, roughly half of other studied Diomedea colonies^15,16,20,21. In January 2008, 1,764 adult albatrosses were incubating eggs on Gough but only 246 chicks survived to fledging²². Outside the breeding season, it disperses to South Atlantic and South African waters²⁸, with numerous recent records from Brazilian waters^8,9 and one from Australia¹⁴, suggesting that birds may occasionally disperse into the Indian Ocean. This is supported by the recent record of a ringed individual washed up on the Indian Ocean coast of South Africa²⁷.
Countries:	Native: Angola; Argentina; Brazil; Namibia; Saint Helena; South Africa; United States; United States; United States; United States; United States; Uruguay
Range Map:	Click here to open the map viewer and explore range.

Population [top]

Population:	Breeding populations are essentially restricted to Gough Island. The annual breeding population is estimated to be 2,700 pairs, equivalent to a total population of 11,300 birds for this biennially breeding species (Wanless et al. 2009).
Population Trend:	Decreasing

Habitat and Ecology [top]

Habitat and Ecology:	Behaviour It is a colonial, biennially breeding species. Adults return in November and December, lay in January and the chicks fledge in November. Immature birds begin returning to their breeding colony at 3-7 years after fledging. Most D. dabbenena recruit in their natal colony, at a mean age of 10 years (range 4-20 years)²⁶. The oldest recorded bird was at least 38 years old²⁷. It catches prey by surface-seizing, and the prevalence of a bioluminescent group of cephalopods in one dietary study suggests that D. dabbenena often feed at night²⁶. During the breeding season the length and range of foraging trips varies considerably, depending on the stage of the breeding cycle^17,19. Habitat Breeding It nests at 400-700 m (rarely to 300 m)¹³, primarily in wet heath where it is open enough for take-off and landings. Diet It feeds on cephalopods and fish³, and probably follows ships and trawlers for offal and galley refuse.
Systems:	Terrestrial; Marine

Habitat and Ecology:

Behaviour It is a colonial, biennially breeding species. Adults return in November and December, lay in January and the chicks fledge in November. Immature birds begin returning to their breeding colony at 3-7 years after fledging. Most D. dabbenena recruit in their natal colony, at a mean age of 10 years (range 4-20 years)²⁶. The oldest recorded bird was at least 38 years old²⁷. It catches prey by surface-seizing, and the prevalence of a bioluminescent group of cephalopods in one dietary study suggests that D. dabbenena often feed at night²⁶. During the breeding season the length and range of foraging trips varies considerably, depending on the stage of the breeding cycle^17,19. Habitat Breeding It nests at 400-700 m (rarely to 300 m)¹³, primarily in wet heath where it is open enough for take-off and landings. Diet It feeds on cephalopods and fish³, and probably follows ships and trawlers for offal and galley refuse.

Systems:

Terrestrial; Marine

Threats [top]

Major Threat(s):	On Inaccessible Island, its decline was probably due to predation by feral pigs (now absent) and humans^7,12. The failure to recover is unclear, but may be because young birds become entangled in thick vegetation^12,13. On Tristan, its extirpation was probably the result of human exploitation³, although predation by rats may have been a factor⁷. On Gough, predation by the introduced house mouse Mus musculus causes very low breeding success and alone is sufficient to drive a population decline of over 50% over three generations^15,16,21. An additional threat on Gough is peat slips caused by storms burying and killing nestlings and adults, although this is probably a very rare event¹¹. The main threat comes from interactions with longline fisheries, with a high proportion of "Wandering" Albatross bycatch in southern Brazilian waters being of this species^8,9, including a few birds banded at Gough^3,6. It has been estimated that c.500 individuals of this species are killed every year by longliners²⁸. Satellite tracking of breeding birds indicates considerable overlap between birds and areas of longline fishing¹⁷, although due to lag times associated with albatross demography we are probably only now likely to start to pick up population trends associated with longline mortality²⁰. Together, the dual threats of mice and bycatch give a worst-case scenario of extinction in roughly 30 years, although the true situation is likely a continued and severe decline²⁴. Having a distribution on relatively low-lying islands, this species is also potentially susceptible to climate change through sea-level rise and shifts in suitable climatic conditions²⁵.

Major Threat(s):

On Inaccessible Island, its decline was probably due to predation by feral pigs (now absent) and humans^7,12. The failure to recover is unclear, but may be because young birds become entangled in thick vegetation^12,13. On Tristan, its extirpation was probably the result of human exploitation³, although predation by rats may have been a factor⁷. On Gough, predation by the introduced house mouse Mus musculus causes very low breeding success and alone is sufficient to drive a population decline of over 50% over three generations^15,16,21. An additional threat on Gough is peat slips caused by storms burying and killing nestlings and adults, although this is probably a very rare event¹¹. The main threat comes from interactions with longline fisheries, with a high proportion of "Wandering" Albatross bycatch in southern Brazilian waters being of this species^8,9, including a few birds banded at Gough^3,6. It has been estimated that c.500 individuals of this species are killed every year by longliners²⁸. Satellite tracking of breeding birds indicates considerable overlap between birds and areas of longline fishing¹⁷, although due to lag times associated with albatross demography we are probably only now likely to start to pick up population trends associated with longline mortality²⁰. Together, the dual threats of mice and bycatch give a worst-case scenario of extinction in roughly 30 years, although the true situation is likely a continued and severe decline²⁴. Having a distribution on relatively low-lying islands, this species is also potentially susceptible to climate change through sea-level rise and shifts in suitable climatic conditions²⁵.

Conservation Actions [top]

Conservation Actions:	Conservation Actions Underway ACAP Annex 1. On Tristan, a programme to eradicate cats was successful in the 1970s. Gough and Inaccessible are nature reserves and Gough is a World Heritage Site. Both islands are uninhabited, apart from a meteorological station on Gough². Satellite tracking to determine foraging areas during the breeding season was undertaken in 2000-2001¹⁵. Censuses of large chicks and/or incubating adults were carried out during 1999-2003, and a monitoring protocol was devised¹⁸. Satellite tracking of non-breeders, further monitoring and demographic work, and an investigation of mouse predation on chicks was initiated during 2003-2006. Initial results from a feasibility study into the removal of the mice appear promising, giving no significant obstacles to the undertaking of an eradication programme²². Since 2007, birds have been marked with field-readable plastic leg rings, and by 2009, 650 individuals had been ringed²⁸. Conservation Actions Proposed Annually survey numbers and assess breeding success on Gough. Continue research of at-sea distribution and foraging behaviour, particularly of non-breeding birds. Promote adoption of best-practice mitigation measures in all fisheries within the species's range, particularly via intergovernmental mechanisms such as ACAP, FAO and Regional Fisheries Management Organisations. Use decoys to assist re-establishment of birds on Tristan, and to attract birds to Long Ridge on Inaccessible¹³. Begin an eradication programme for mice on Gough Island as soon as possible.

Conservation Actions:

Conservation Actions Underway
ACAP Annex 1. On Tristan, a programme to eradicate cats was successful in the 1970s. Gough and Inaccessible are nature reserves and Gough is a World Heritage Site. Both islands are uninhabited, apart from a meteorological station on Gough². Satellite tracking to determine foraging areas during the breeding season was undertaken in 2000-2001¹⁵. Censuses of large chicks and/or incubating adults were carried out during 1999-2003, and a monitoring protocol was devised¹⁸. Satellite tracking of non-breeders, further monitoring and demographic work, and an investigation of mouse predation on chicks was initiated during 2003-2006. Initial results from a feasibility study into the removal of the mice appear promising, giving no significant obstacles to the undertaking of an eradication programme²². Since 2007, birds have been marked with field-readable plastic leg rings, and by 2009, 650 individuals had been ringed²⁸.

Conservation Actions Proposed
Annually survey numbers and assess breeding success on Gough. Continue research of at-sea distribution and foraging behaviour, particularly of non-breeding birds. Promote adoption of best-practice mitigation measures in all fisheries within the species's range, particularly via intergovernmental mechanisms such as ACAP, FAO and Regional Fisheries Management Organisations. Use decoys to assist re-establishment of birds on Tristan, and to attract birds to Long Ridge on Inaccessible¹³. Begin an eradication programme for mice on Gough Island as soon as possible.

Citation:	BirdLife International 2010. Diomedea dabbenena. In: IUCN 2011. IUCN Red List of Threatened Species. Version 2011.2. <www.iucnredlist.org>. Downloaded on 24 May 2012.
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