Africa, Europe and Central Asia
This discussion was first published as part of the 2021 Red List update. At the time a decision regarding its status was pended, but to enable potential reassessment of this species as part of the 2022 Red List update this post remained open and the date of posting has been updated.
The population model by Jones et al. 2021 projecting the decline of the species was based on nearly total breeding failure due to mouse predation. A mouse eradication attempt on Gough Island occurred in June-August 2021, which killed a large proportion of the island’s mice. Unfortunately, however, mice are still present on Gough Island and the working assumption is that some mice survived the eradication attempt. The mouse population is currently well below carrying capacity and it is not known how long it will take for it to reach carrying capacity. Furthermore, whether the seabird predation behaviour persists in the remaining mouse population – or how long it may take to re-emerge – is unknown. At present it is unknown how breeding success of the species has changed in the near-absence of mice (we will only know by April 2022). We therefore endorse the uplisting at this time, because no successful action has been taken that could guarantee a long-term improvement of breeding success on Gough Island.
Many thanks to everyone who has contributed to this discussion. We greatly appreciate the time and effort invested by so many people in commenting. The window for consultation is now closed and we are unable to accept any more comments until 21 February 2022. We will now analyse and interpret the new information, and we will post a preliminary decision on this species’s Red List status on this page on 21 February 2022, when discussions will re-open.
Preliminary proposal
Based on available information regarding the mouse eradication attempt, our preliminary proposal for the 2022.1 Red List would be to adopt the proposed classifications outlined in the initial forum discussion.
There is now a period for further comments until the final deadline on 27 February 2022, after which the recommended categorisations will be put forward to IUCN.
The final 2022.1 Red List categories will be published on the BirdLife and IUCN websites in July 2022, following further checking of information relevant to the assessments by both BirdLife and IUCN.
I endorse the re-categorizing of MacGillivray’s Prion to Critically Endangered and echo sentiments expressed by Steffen Oppel.
Just some points to clarify in your species data text:
1. Update the sections on population size and geographic range regarding the Indian Ocean population. Barbraud et al. (2021) surveyed Saint-Paul Island 20 years after the successful eradication of invasive black rat (Rattus rattus) and European rabbit (Oryctolagus cuniculus). They found that MacGillivray’s Prion (among other seabirds) have re-colonized the island with a rough estimate of 740 breeding pairs (in addition to the Roche Quille population). While this is encouraging and an important status update of this population, the long-term prospects of this population remain uncertain considering invasive mice are still present on Saint-Paul. Hence, should not affect the decision to adopt a critically endangered classification.
2. While area of occupation (AOO) is imprecisely known, Jones (2018) estimates that AOO for MacGillivray’s Prion is 40-50% of the total area of Gough Island, approximately 26 – 33 km2. Again, this should not affect the decision to adopt a CR classification but important to have the correct AOO (to the best of our knowledge).
3. Extent of occurrence (EOO) is given as 10 800 000 km2 which is spuriously precise and very likely a gross underestimate. Jones et al. (2020) present at-sea movements of MacGillivray’s Prions from Gough Island using tracking data from geolocation loggers and based on this EOO is at least 20 million km2 in the South Atlantic Ocean. This does not consider the EOO of the Indian Ocean population. Thus, EOO is likely >20 000 000 km2.
Barbraud, C., Delord, K., Le Bouard, F., Harivel, R., Demay, J., Chaigne, A., & Micol, T. (2021). Seabird population changes following mammal eradication at oceanic Saint-Paul Island, Indian Ocean. Journal for Nature Conservation, 63, 126049.
Jones, C. W. P. (2018). Comparative ecology of Pachyptila species breeding sympatrically at Gough Island (Master’s thesis, University of Cape Town).
Jones, C. W., Phillips, R. A., Grecian, W. J., & Ryan, P. G. (2020). Ecological segregation of two superabundant, morphologically similar, sister seabird taxa breeding in sympatry. Marine Biology, 167(4), 1-16.
Many thanks to everyone who has contributed to this discussion. We greatly appreciate the time and effort invested by so many people in commenting. The window for consultation is now closed and we are unable to accept any more comments. We will analyse and interpret the new information, and we will post a final decision on this species’ Red List status on this page on 7 March 2022.
Recommended categorisation to be put forward to IUCN
The final categorisation for this species has not changed, but the account for this species has been updated to incorporate additional information from this discussion. MacGillivray’s Prion is recommended to be listed as Critically Endangered under Criteria A3be+4be.
Many thanks for everyone who contributed to the 2022.1 GTB Forum process. The final 2022.1 Red List categories will be published on the BirdLife and IUCN websites in July 2022, following further checking of information relevant to the assessments by both BirdLife and IUCN.