7 thoughts on “Pitcairn Reed-warbler (Acrocephalus vaughani)”
Would not this species’ range throughout a single small island (being in effect a single continuous population) meet the definition of a single location: “a geographically or ecologically distinct area in which a single threatening event can rapidly affect all individuals of the taxon present”? Such an event could include the introduction of a disease agent or an efficient predator, despite the species’ survival in the presence of cats and rats. If so, the species would meet criterion D2, as well as D1, for VU. It would also meet B1(a) for CR but this would not be enough to assess the species as CR.
I agree that this species occurs only at a single location (Pitcairn island), but based on available information the proposed status change from EN to VU is appropriate and consistent with current knowledge. The habitat loss and/or degradation has very likely resulted in past population changes, but apart from some soil erosion there is currently no major threat to the existing habitat, or directly to the species. The species therefore does not meet any of the population decline (suspected, inferred, or estimated) thresholds that would be necessary for an EN or CR listing, and VU is an appropriate category.
Many thanks to everyone who has contributed to this discussion. We greatly appreciate the time and effort invested in commenting. The window for consultation is now closed and we are unable to accept any more comments until 2 February 2026. We will now analyse and interpret the information, and we will post a preliminary decision on this species’ Red List category on this page on 2 February 2026, when discussions will re-open.
The term ‘location’ defines a geographically or ecologically distinct area in which a single threatening event can rapidly affect all individuals of the taxon present, and it is determined by the most serious plausible threat to the taxon. According to the IUCN guidelines, there must be a substantial possibility of such an event actually occurring, and unlikely or non-specific events (e.g. an unspecified disease epidemic not observed in similar species) would not qualify for listing under Criterion D2. Although this species’ range is highly restricted, in the absence of such a plausible threat it is not currently considered to occur at a single ‘location’ or to meet the requirements for Criterion D2.
Based on available information therefore, our preliminary proposal for the 2026 Red List would be to adopt the proposed classification outlined in the initial forum discussion.
There is now a period for further comments until the final deadline on 8 February 2026, after which the recommended categorisations will be put forward to IUCN.
The final 2026 Red List categories will be published on the BirdLife and IUCN websites later this year, following further checking of information relevant to the assessments by both BirdLife and IUCN.
Joint submission from the Pitcairn Government Department of Natural Resources and the RSPB: We agree with the reclassification based on the evidence in Oppel et al. (2024) but note that gaps remain in our understanding of this species’ biology. The presence of feral cats on Pitcairn remains a potential threat to the Pitcairn Reed Warbler. Oppel et al. (2024) also shows that this species prefers Rose Apple (Syzygium jambos) stands which is an introduced species. There are no plans to control Rose Apple at present but any future work to control it could have negative knock-on effects on Pitcairn Reed Warblers. This may be mitigated to some extent by Pitcairn Reed Warbler’s ability to use a variety of different habitat types on Pitcairn (Oppel et al. 2024, Pitcairn Government observations).
Many thanks to everyone who has contributed to this discussion. We greatly appreciate the time and effort invested in commenting. The window for consultation is now closed and we are unable to accept any more comments. We will analyse and interpret the information, and a final decision on this species’ Red List category will be posted on this page on 16 February 2026.
Recommended categorisation to be put forward to IUCN
We thank all contributors for their comments. Following further review of the threats affecting this species, and clarification of the potential threat posed by the introduction of other Rattus species, it is considered to meet the thresholds for Vulnerable under Criterion D2 as well as D1. Although it appears to coexist with Pacific Rats (Rattus exulans) and feral cats (Felis catus), the potential introduction of other Rattus species (e.g. R. rattus or R. norvegicus) represents a plausible threat that could rapidly cause major population declines or extinction, as has occurred in other insular Acrocephalus populations.
Pitcairn Reed-warbler is therefore recommended to be listed as Vulnerable under Criteria D1+2.
Many thanks to everyone who contributed to the 2026.1 GTB Forum process. The final Red List categories will be published on the BirdLife and IUCN websites later this year, following further checking of information relevant to the assessments by both BirdLife and IUCN.
Would not this species’ range throughout a single small island (being in effect a single continuous population) meet the definition of a single location: “a geographically or ecologically distinct area in which a single threatening event can rapidly affect all individuals of the taxon present”? Such an event could include the introduction of a disease agent or an efficient predator, despite the species’ survival in the presence of cats and rats. If so, the species would meet criterion D2, as well as D1, for VU. It would also meet B1(a) for CR but this would not be enough to assess the species as CR.
I agree that this species occurs only at a single location (Pitcairn island), but based on available information the proposed status change from EN to VU is appropriate and consistent with current knowledge. The habitat loss and/or degradation has very likely resulted in past population changes, but apart from some soil erosion there is currently no major threat to the existing habitat, or directly to the species. The species therefore does not meet any of the population decline (suspected, inferred, or estimated) thresholds that would be necessary for an EN or CR listing, and VU is an appropriate category.
Many thanks to everyone who has contributed to this discussion. We greatly appreciate the time and effort invested in commenting. The window for consultation is now closed and we are unable to accept any more comments until 2 February 2026. We will now analyse and interpret the information, and we will post a preliminary decision on this species’ Red List category on this page on 2 February 2026, when discussions will re-open.
Preliminary proposal
We thank all contributors for their comments.
The term ‘location’ defines a geographically or ecologically distinct area in which a single threatening event can rapidly affect all individuals of the taxon present, and it is determined by the most serious plausible threat to the taxon. According to the IUCN guidelines, there must be a substantial possibility of such an event actually occurring, and unlikely or non-specific events (e.g. an unspecified disease epidemic not observed in similar species) would not qualify for listing under Criterion D2. Although this species’ range is highly restricted, in the absence of such a plausible threat it is not currently considered to occur at a single ‘location’ or to meet the requirements for Criterion D2.
Based on available information therefore, our preliminary proposal for the 2026 Red List would be to adopt the proposed classification outlined in the initial forum discussion.
There is now a period for further comments until the final deadline on 8 February 2026, after which the recommended categorisations will be put forward to IUCN.
The final 2026 Red List categories will be published on the BirdLife and IUCN websites later this year, following further checking of information relevant to the assessments by both BirdLife and IUCN.
Joint submission from the Pitcairn Government Department of Natural Resources and the RSPB: We agree with the reclassification based on the evidence in Oppel et al. (2024) but note that gaps remain in our understanding of this species’ biology. The presence of feral cats on Pitcairn remains a potential threat to the Pitcairn Reed Warbler. Oppel et al. (2024) also shows that this species prefers Rose Apple (Syzygium jambos) stands which is an introduced species. There are no plans to control Rose Apple at present but any future work to control it could have negative knock-on effects on Pitcairn Reed Warblers. This may be mitigated to some extent by Pitcairn Reed Warbler’s ability to use a variety of different habitat types on Pitcairn (Oppel et al. 2024, Pitcairn Government observations).
Many thanks to everyone who has contributed to this discussion. We greatly appreciate the time and effort invested in commenting. The window for consultation is now closed and we are unable to accept any more comments. We will analyse and interpret the information, and a final decision on this species’ Red List category will be posted on this page on 16 February 2026.
Recommended categorisation to be put forward to IUCN
We thank all contributors for their comments. Following further review of the threats affecting this species, and clarification of the potential threat posed by the introduction of other Rattus species, it is considered to meet the thresholds for Vulnerable under Criterion D2 as well as D1. Although it appears to coexist with Pacific Rats (Rattus exulans) and feral cats (Felis catus), the potential introduction of other Rattus species (e.g. R. rattus or R. norvegicus) represents a plausible threat that could rapidly cause major population declines or extinction, as has occurred in other insular Acrocephalus populations.
Pitcairn Reed-warbler is therefore recommended to be listed as Vulnerable under Criteria D1+2.
Many thanks to everyone who contributed to the 2026.1 GTB Forum process. The final Red List categories will be published on the BirdLife and IUCN websites later this year, following further checking of information relevant to the assessments by both BirdLife and IUCN.