CR
MacGillivray's Prion Pachyptila macgillivrayi



Taxonomy
IUCN Red List criteria met and history
Red List criteria met
Critically Endangered Endangered Vulnerable
A3be+4be A3be+4be; B2ab(v) A3be+4be; B2ab(v); D2

Red List history
Year Category Criteria
2022 Critically Endangered A3be+4be
2018 Endangered B2ab(v)
2016 Endangered B2ab(v)
2012 Not Recognised
2008 Not Recognised
2004 Not Recognised
2000 Not Recognised
1994 Not Recognised
1988 Not Recognised
Species attributes

Migratory status full migrant Forest dependency does not normally occur in forest
Land-mass type Average mass 159 g
Range

Estimate Data quality
Number of locations 2-10 -
Severely fragmented? no -
Population
Estimate Data quality Derivation Year of estimate
Population size 48300-2421480 mature individuals poor estimated 2020
Population trend decreasing - inferred 2020-2054
Rate of change over the future 10 years/3 generations (longer of the two periods) 95.7% - - -
Rate of change over the past & future 10 years/3 generations (longer of the two periods) 95.7% - - -
Generation length 11.15 years - - -

Population justification: Jones et al. (2021) estimate the population on Gough in 2020 to be 175,000 pairs (95% CI 24,000-1,210,000 pairs [48,000-2,420,000 mature individuals). An additional 150-200 breeding pairs (c.300-400 mature individuals) were estimated to be present on Roche Quille, Île Saint-Paul (Jiguet et al. 2007). Following the successful eradication of the Black Rat (Rattus rattus) and European Rabbit (Oryctolagus cuniculus), surveys showed an increase in numbers with a rough estimate of 740 breeding pairs (Barbraud et al. 2021). However, mice are still present on Saint-Paul, so the long term prospects of this population remain unknown (C. W. Jones in litt. 2022). The population size is therefore estimated to be in the range of 48,300-2,421,480 mature individuals.

Trend justification: This species is inferred to be declining as it is currently suffering a very high chick mortality rate as a result of nest predation by mice (Dilley et al. 2015). These declines are projected to occur at a rate of 9% per annum over the next 36 years (Jones et al. 2021), a rate equivalent to 95.7% over three generation lengths (33.45 years [Bird et al. 2020]). A mouse eradication attempt on Gough Island occurred in June-August 2021, and although this killed a large proportion of the island's mice, some mice did survive the attempt (S. Oppel in litt. 2022). Although it is unknown how long it will take mice to reach carrying capacity, it is likely there will be no long-term improvement in breeding success that could counteract the current projected declines.


Country/territory distribution
Country/Territory Presence Origin Resident Breeding visitor Non-breeding visitor Passage migrant
French Southern Territories extant native yes
St Helena (to UK) extant native yes

Important Bird and Biodiversity Areas (IBA)
Country/Territory IBA Name
French Southern Territories Île aux Cochons
French Southern Territories Île de l'Est
French Southern Territories Île de la Possession
French Southern Territories Îles des Apôtres
South Africa Prince Edward Islands Special Nature Reserve

Habitats & altitude
Habitat (level 1) Habitat (level 2) Importance Occurrence
Caves and Subterranean Habitats (non-aquatic) Caves suitable breeding
Grassland Subantarctic major breeding
Marine Neritic Pelagic major breeding
Marine Neritic Pelagic major non-breeding
Marine Oceanic Epipelagic (0-200m) major breeding
Marine Oceanic Epipelagic (0-200m) major non-breeding
Altitude 0 - 300 m Occasional altitudinal limits  

Threats & impact
Threat (level 1) Threat (level 2) Impact and Stresses
Invasive and other problematic species, genes & diseases Invasive non-native/alien species/diseases - Mus musculus Timing Scope Severity Impact
Ongoing Majority (50-90%) Very Rapid Declines High Impact: 8
Stresses
Reduced reproductive success, Species mortality
Invasive and other problematic species, genes & diseases Invasive non-native/alien species/diseases - Named species Timing Scope Severity Impact
Past, Likely to Return Minority (<50%) Slow, Significant Declines Past Impact
Stresses
Species mortality
Invasive and other problematic species, genes & diseases Invasive non-native/alien species/diseases - Named species Timing Scope Severity Impact
Past, Unlikely to Return Minority (<50%) Very Rapid Declines Past Impact
Stresses
Reduced reproductive success, Species mortality

Recommended citation
BirdLife International (2024) Species factsheet: MacGillivray's Prion Pachyptila macgillivrayi. Downloaded from https://datazone.birdlife.org/species/factsheet/macgillivrays-prion-pachyptila-macgillivrayi on 24/11/2024.
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 24/11/2024.