10 thoughts on “Barolo Shearwater (Puffinus baroli)”
There is another reference missing. In 2010, the Atlas Team conducted the first breeding bird Atlas of the Madeira Archipelago.
On the scope of this work, a directed census was done for marine birds, including Puffinus baroli.
For this specie, breeding was confirmed in Selvagens (Selvagem Grande and Selvagem Pequena), in Madeira Island (in Ponta de São Lourenço) and in two Porto Santo islets (ilhéu de Baixo e ilhéu de Ferro).
No estimation of the population was done, but this information can complete the breeding range of the specie.
This work should be referenced as “Equipa Atlas (2013). Atlas das Aves Nidificantes do Arquipélago da Madeira 2009-2011. IFCN, IP-RAM. Portugal.”
Although I don’t have recent data regarding the breeding population on Selvagens and Porto Santo, I confirm that over the last few years, this is the most difficult species to see at sea around the Madeira archipelago, probably due to small population size.
I agree with the proposed Red List category.
The reference Pipa et al., 2023, should be update to Pipa et al., 2024. Complete reference : Pipa, T., Martins, B., Silva, C., Heber, S., Magalhães, M., Carriço, R., Câmara, R., Lourenço, J., Aguiar, L., Cunha, B., Raposo, P., Raposo, A., Coelho, R., Huamán, M., Pinto, F., Sequeira, R., Carreira, G., Pereira, D., De la Cruz, A (2024). Monitorização de aves marinhas Procellariiformes 2020-2023: Relatório da Ação D5.1. (unpublished report). Projeto LIFE IP AZORES NATURA – LIFE17 IPE/PT/00010.
Also the species was detected in Terceira island through passive acoustic monitoring in 2019-2020 and 2021 (Ruben Coelho & Carlos Pereira in pers comm 2019-2020; Tânia Pipa & Ruben Coelho in pers comm 2021).
The results obtained from the seabird census carried out under the INTERREG MAC Luminaves project (conducted in 2017 and 2018) corroborate the negative trend observed in the pintainho population on Madeira Island (no birds detected).
Within the LIFE4BEST Seabird Macaronesian Sound project (2021 and 2022), the species was detected (by ARUs) in only three coastal locations, in very low numbers, suggesting the presence of passing adults. Overall, the population is small, and there are no data available on population estimates or trends, a situation that is particularly concerning when considering the general threats faced by seabirds on the island.
SPEA 2021. Relatório Final do Projeto LuMinAves. Actividad 2.1.1 Estudio y censo de las poblaciones de aves marinas en las colonias de cría. Sociedade Portuguesa para o Estudo das Aves, Funchal (relatório não publicado).
SPEA, 2021. LIFE4BEST Seabird Macaronesian Sound Final Report, Sociedade Portuguesa para o Estudo das Aves (not published).
We agree with the evaluation and consider that the species merits conservation attention. Actually, given an overall severe decline (that might be well ober 50% in some important colonies) and high uncertainty in population estimates (some of them old, which means that the current population might be below 2500 mature individuals), we’d propose the category Endangered (EN), under a precautionary approach:
C1. Although the minimum estimate is of 2191 breeding pairs, it is worth noting that this figure might be overestimated, given than most information comes from several years ago, and is based in methods subject to high uncertainty. The information from Salvagem in 2024-2025 (four birds recorded “at any one time”) is of particular concern, as the population there (the supposed stronghold of the species) might certainly be well below 1000 bp. Note also that information for Desertas is uncertain and old, and according to inputs from SPEA in Madeira, the situation there seems also bad. Only Azores seems to be stable, as far as the available information indicates. On the other hand, the observed decline is consistent with over 20% in two generations.
A3. A Given the alarming decline of the Salvagem population (the species’ stronghold), that might be up to 64% (or even higher, if we take into account the alarming information of 2024-2025), it might be appropriate to propose EN, under a precautionary point of view. Note also that the Canary Islands population decline is estimated at about 70% in three generations, while information from Madeira is unclear and seems bad (more so for Desertas). Only the Azores seem to keep a stable population. Moreover, it is important to note that causes of decline are not fully understood, and certainly not halted.
Note also that, given that the species is concentrated in a relatively small number of sites, some of them holding a significant fraction of the global population, any further deterioration in a single colony could translate into an immediate reduction. This demographic structure increases the risk of extinction and is consistent with a more severe category when threats are not controlled.
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.
We received the following comment from Paulo Catry while the forum was temporarily closed:
The numbers on Selvagens seem to have declined massively. The causes are unknown. Predation is unlikely to be important, other petrels are doing well on Selvagens, and there are currently no introduced mammals. Competition with Cory’s shearwaters (which are increasing) could help explaining a little of the trend, but Cory’s shearwaters use much larger cavities, so they are unlikely to be the main drivers of decline. It seems more likely that the causes are marine-based, but this is speculative and there are no strong hypotheses that I am aware of. The species also seem to now be quite rare on Desertas islands. I agree with the suggestion that the species should be declared Endangered, rather than Vulnerable.
We would like to thank all contributors for their comments. We will incorporate all information provided and will update the references and range map accordingly.
We note concerns raised by P. Arcos and Y. Acosta on the forum, and by B. Vercruysse via email, that the species should be listed as Endangered because the population on Selvagem Grande may be smaller than is stated in this assessment. The maximum rate of reduction (46% over three generations in the window 1995-2041) and minimum population size (4,400 mature individuals) were calculated according to the ‘worst-case’ scenario based on available quantitative data. The minimum population size assumes that the Selvagem Grande population has continued to decline from 2013-2025 at the same rate measured from 1995-2013. It also assumes declines in the Canary Islands population from 800 mature individuals in 1985 to 316 in 2021, and disregards uncertain estimates of 300 individuals on Desertas Island. Considering there is a minimum of roughly 1,680 mature individuals in a stable population on the Azores, the current Selvagem Grande population has not been quantified, and it has been noted that the species also breeds on Selvagem Pequena where the population size is unquantified, the balance of evidence suggests there is likely more than 2,500 mature individuals globally and the species therefore does not meet the thresholds for Endangered under Criterion C.
Likewise, the maximum rate of decline uses the minimum population sizes defined above. A maximum rate of 46% over three generations is calculated by assuming the rate of decline measured from 1995-2013 on Selvagem Grande and from 1985-2021 on the Canaries, will continue until 2041. We note that the Madeiran population may also be declining, but because this constitutes such a small proportion of the global population (c. 258 individuals), even the complete collapse of this population does not result in an overall global reduction >50% by 2041. Recent observations by B. Vercruysse and colleagues indicate that the Selvagem Grande population may be smaller and therefore declining more rapidly. However, as there has been no updated quantitative trend or census data for Selvagem Grande and the size and status of the population on Selvagem Pequena is unknown, it is deemed overly precautionary to assume declines exceeding what is known from the 1995-2013 monitoring data, especially considering the uncertainty inherent with projecting long-term trends for long-lived taxa.
Based on available information, our preliminary proposal for the 2026 Red List would be to adopt the proposed classification outlined in the initial forum discussion. Updated quantitative trend/census data for Selvagem Grande and Selvagem Pequena would allow a revaluation of the population size and rate of population reduction.
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.
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 received the following comment from Pep Arcos and Yarci Acosta (SEO/BirdLife) after the forum was closed:
“Added to our already exposed concerns, the message of Paulo Catry about Salvagem (massive decline due to unknown causes) also merits attention.
Given the apparent severe decline of this stronghold (Salvagem), which also affects to Madeira/Desertas/Canary Islands, and the high degree of uncertainty, would make sensible to go for EN, under a precautionary approach.
Most estimates have not been updated in the last 10-20 years, which coupled with the perceived decline, suggest that even 4400 mature individuals could be far from the real situation nowadays.
The documented declines could, on the other hand, exceed the 20% in two generations, thus accomplishing EN under C1.
The Guidelines (sections 4.6 and 4.7) state that when a significant proportion of the global population is concentrated in a few declining subpopulations, the risk of extinction increases in a direct and quantifiable way. In this case, the loss or deterioration of a single colony implies an immediate reduction of >30–40% of the global population, according to the available numerical values. In this regard, the Guidelines (section 3.2) establish that: (1) uncertainty must not be resolved toward the least threatened option; (2) the plausible lower bound must be used when data gaps exist; (3) the decision must be precautionary and credible; and (4) the absence of recent data cannot be interpreted as stability.”
We recognise that there is concern that the Selvagem Grande population may be smaller than is reported in this assessment and that a precautionary approach should be taken when estimating minimum population sizes and maximum population reductions. We would like to reiterate that this assessment has already applied a precautionary approach for the population size and population reduction based on the available quantitative data. The minimum population size is derived as follows:
Selvagem Grande: minimum set to 1,064 pairs, calculated by assuming the rate of decline measured from 1995 (2,050 pairs) to 2013 (1,383 pairs) has continued.
Azores: 840 pairs (Monteiro et al. 1999, Equipa Atlas 2022, Pipa et al. 2024, OSPAR 2025).
Madeira: 129 pairs (minimum from 2009-2021 according to estimates for Selvagens and Madeira from Ramos 2013, SPNM 2015, 2016, Ramos et al. 2021, Equipa Atlas 2022, OSPAR 2025).
Desertas: minimum set to zero because there are no certain quantified estimates
Canary Islands: 158 pairs between 2019 and 2024 (SEO/BirdLife 2025)
Together, this gives a total minimum estimated population size of 2,191 pairs or 4,382 mature individuals. We recognise that the Selvagem Grande population may be lower than the estimate provided here. However, lacking any recent quantitative data, we have determined that projecting measured declines to 2025 provides the most precautionary and credible population size possible at this time. This is also considering that there are an unknown number of birds nesting on Selvagem Pequena that have not been considered in this population estimate.
While we recognise that some of these population estimates are not 2025 estimates, the absence of recent data is not interpreted as stability for this assessment. The stable trend for the Azores is based on reported trends (see Equipa Atlas 2022, Pipa et al. 2023, OSPAR 2025) not an absence of data. As mentioned, the trend for Selvagem Grande is considered to be declining at the same rate that was measured from 1995 to 2013. Although this trend may have changed, there is no quantitative data to derive the rate, and any assumptions on an accelerated rate of decline would therefore be arbitrary. Using the trend derived from available data, even if it is not current, is thought to be more credible than qualitative data and represents the ‘plausible lower bound’ according to the available information. Thus, the species does not meet the population size threshold (2,500 mature individuals) for Endangered under Criterion C1.
We recognise that extinction risk increases when a significant proportion of the global population is concentrated within a few declining subpopulations. This has been accounted for in this assessment, noting that the IUCN Guidelines stipulates the following when calculating reductions across multiple populations:
(4.5.4) – “All available data should be used to calculate a reduction as an average over all subpopulations, weighted by the estimated size of each subpopulation at the beginning of the period. Inferences regarding reductions should not be based on information for any single subpopulation (whether it is the fastest declining, most stable, largest or smallest)”.
(4.5.5) Using data from a few subpopulations – data should only be used from a single subpopulation “If there is no information on the rest of the subpopulations…” and “If it can be assumed that all (or all the large) subpopulations are declining at the same rate”.
Because there is sufficient information from the other populations, and the available information indicates they are not all declining at the same rate as Selvagem Grande, all populations are included in the reduction calculation, and it is weighted by the size of each population. Although the Selvagem Grande population is expected to decline by roughly 64% over three generations (worst-case scenario), the overall reduction is 46% because the Azores holds a significant number of mature individuals and is reportedly stable as outlined above. This scenario also includes a 70% decline in the Canary Islands population. We recognise that the Madeiran population may also be declining, but because this only has a small proportion of the total population, even a 100% reduction over three generations does not result in an overall reduction exceeding 50%. A survey providing updated quantitative population counts for Selvagem Grande (and ideally Selvagem Pequena) would allow a revaluation of this trend and the Categories and Criteria for this species can be reassessed at that time.
The final categorisation for this species has not changed. Barolo Shearwater is recommended to be listed as Vulnerable under Criteria A4b; C1.
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.
There is another reference missing. In 2010, the Atlas Team conducted the first breeding bird Atlas of the Madeira Archipelago.
On the scope of this work, a directed census was done for marine birds, including Puffinus baroli.
For this specie, breeding was confirmed in Selvagens (Selvagem Grande and Selvagem Pequena), in Madeira Island (in Ponta de São Lourenço) and in two Porto Santo islets (ilhéu de Baixo e ilhéu de Ferro).
No estimation of the population was done, but this information can complete the breeding range of the specie.
This work should be referenced as “Equipa Atlas (2013). Atlas das Aves Nidificantes do Arquipélago da Madeira 2009-2011. IFCN, IP-RAM. Portugal.”
All the results of the breeding Atlas https://ifcn.madeira.gov.pt/pt/biodiversidade/projetos/atlas-das-aves-nidificantes-no-arquipelago-da-madeira?format=html#resultados), and the specific breeding map of Puffinus baroli (https://drive.google.com/file/d/1fBvbFJBamUMbsPqWNsYRPjJxXnnTTOPK/view), can be found online.
I agree with the proposed change in the Red List Status.
Although I don’t have recent data regarding the breeding population on Selvagens and Porto Santo, I confirm that over the last few years, this is the most difficult species to see at sea around the Madeira archipelago, probably due to small population size.
I agree with the proposed Red List category.
The reference Pipa et al., 2023, should be update to Pipa et al., 2024. Complete reference : Pipa, T., Martins, B., Silva, C., Heber, S., Magalhães, M., Carriço, R., Câmara, R., Lourenço, J., Aguiar, L., Cunha, B., Raposo, P., Raposo, A., Coelho, R., Huamán, M., Pinto, F., Sequeira, R., Carreira, G., Pereira, D., De la Cruz, A (2024). Monitorização de aves marinhas Procellariiformes 2020-2023: Relatório da Ação D5.1. (unpublished report). Projeto LIFE IP AZORES NATURA – LIFE17 IPE/PT/00010.
Also the species was detected in Terceira island through passive acoustic monitoring in 2019-2020 and 2021 (Ruben Coelho & Carlos Pereira in pers comm 2019-2020; Tânia Pipa & Ruben Coelho in pers comm 2021).
The results obtained from the seabird census carried out under the INTERREG MAC Luminaves project (conducted in 2017 and 2018) corroborate the negative trend observed in the pintainho population on Madeira Island (no birds detected).
Within the LIFE4BEST Seabird Macaronesian Sound project (2021 and 2022), the species was detected (by ARUs) in only three coastal locations, in very low numbers, suggesting the presence of passing adults. Overall, the population is small, and there are no data available on population estimates or trends, a situation that is particularly concerning when considering the general threats faced by seabirds on the island.
SPEA 2021. Relatório Final do Projeto LuMinAves. Actividad 2.1.1 Estudio y censo de las poblaciones de aves marinas en las colonias de cría. Sociedade Portuguesa para o Estudo das Aves, Funchal (relatório não publicado).
SPEA, 2021. LIFE4BEST Seabird Macaronesian Sound Final Report, Sociedade Portuguesa para o Estudo das Aves (not published).
We agree with the evaluation and consider that the species merits conservation attention. Actually, given an overall severe decline (that might be well ober 50% in some important colonies) and high uncertainty in population estimates (some of them old, which means that the current population might be below 2500 mature individuals), we’d propose the category Endangered (EN), under a precautionary approach:
C1. Although the minimum estimate is of 2191 breeding pairs, it is worth noting that this figure might be overestimated, given than most information comes from several years ago, and is based in methods subject to high uncertainty. The information from Salvagem in 2024-2025 (four birds recorded “at any one time”) is of particular concern, as the population there (the supposed stronghold of the species) might certainly be well below 1000 bp. Note also that information for Desertas is uncertain and old, and according to inputs from SPEA in Madeira, the situation there seems also bad. Only Azores seems to be stable, as far as the available information indicates. On the other hand, the observed decline is consistent with over 20% in two generations.
A3. A Given the alarming decline of the Salvagem population (the species’ stronghold), that might be up to 64% (or even higher, if we take into account the alarming information of 2024-2025), it might be appropriate to propose EN, under a precautionary point of view. Note also that the Canary Islands population decline is estimated at about 70% in three generations, while information from Madeira is unclear and seems bad (more so for Desertas). Only the Azores seem to keep a stable population. Moreover, it is important to note that causes of decline are not fully understood, and certainly not halted.
Note also that, given that the species is concentrated in a relatively small number of sites, some of them holding a significant fraction of the global population, any further deterioration in a single colony could translate into an immediate reduction. This demographic structure increases the risk of extinction and is consistent with a more severe category when threats are not controlled.
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.
We received the following comment from Paulo Catry while the forum was temporarily closed:
The numbers on Selvagens seem to have declined massively. The causes are unknown. Predation is unlikely to be important, other petrels are doing well on Selvagens, and there are currently no introduced mammals. Competition with Cory’s shearwaters (which are increasing) could help explaining a little of the trend, but Cory’s shearwaters use much larger cavities, so they are unlikely to be the main drivers of decline. It seems more likely that the causes are marine-based, but this is speculative and there are no strong hypotheses that I am aware of. The species also seem to now be quite rare on Desertas islands. I agree with the suggestion that the species should be declared Endangered, rather than Vulnerable.
Preliminary proposal
We would like to thank all contributors for their comments. We will incorporate all information provided and will update the references and range map accordingly.
We note concerns raised by P. Arcos and Y. Acosta on the forum, and by B. Vercruysse via email, that the species should be listed as Endangered because the population on Selvagem Grande may be smaller than is stated in this assessment. The maximum rate of reduction (46% over three generations in the window 1995-2041) and minimum population size (4,400 mature individuals) were calculated according to the ‘worst-case’ scenario based on available quantitative data. The minimum population size assumes that the Selvagem Grande population has continued to decline from 2013-2025 at the same rate measured from 1995-2013. It also assumes declines in the Canary Islands population from 800 mature individuals in 1985 to 316 in 2021, and disregards uncertain estimates of 300 individuals on Desertas Island. Considering there is a minimum of roughly 1,680 mature individuals in a stable population on the Azores, the current Selvagem Grande population has not been quantified, and it has been noted that the species also breeds on Selvagem Pequena where the population size is unquantified, the balance of evidence suggests there is likely more than 2,500 mature individuals globally and the species therefore does not meet the thresholds for Endangered under Criterion C.
Likewise, the maximum rate of decline uses the minimum population sizes defined above. A maximum rate of 46% over three generations is calculated by assuming the rate of decline measured from 1995-2013 on Selvagem Grande and from 1985-2021 on the Canaries, will continue until 2041. We note that the Madeiran population may also be declining, but because this constitutes such a small proportion of the global population (c. 258 individuals), even the complete collapse of this population does not result in an overall global reduction >50% by 2041. Recent observations by B. Vercruysse and colleagues indicate that the Selvagem Grande population may be smaller and therefore declining more rapidly. However, as there has been no updated quantitative trend or census data for Selvagem Grande and the size and status of the population on Selvagem Pequena is unknown, it is deemed overly precautionary to assume declines exceeding what is known from the 1995-2013 monitoring data, especially considering the uncertainty inherent with projecting long-term trends for long-lived taxa.
Based on available information, our preliminary proposal for the 2026 Red List would be to adopt the proposed classification outlined in the initial forum discussion. Updated quantitative trend/census data for Selvagem Grande and Selvagem Pequena would allow a revaluation of the population size and rate of population reduction.
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.
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 received the following comment from Pep Arcos and Yarci Acosta (SEO/BirdLife) after the forum was closed:
“Added to our already exposed concerns, the message of Paulo Catry about Salvagem (massive decline due to unknown causes) also merits attention.
Given the apparent severe decline of this stronghold (Salvagem), which also affects to Madeira/Desertas/Canary Islands, and the high degree of uncertainty, would make sensible to go for EN, under a precautionary approach.
Most estimates have not been updated in the last 10-20 years, which coupled with the perceived decline, suggest that even 4400 mature individuals could be far from the real situation nowadays.
The documented declines could, on the other hand, exceed the 20% in two generations, thus accomplishing EN under C1.
The Guidelines (sections 4.6 and 4.7) state that when a significant proportion of the global population is concentrated in a few declining subpopulations, the risk of extinction increases in a direct and quantifiable way. In this case, the loss or deterioration of a single colony implies an immediate reduction of >30–40% of the global population, according to the available numerical values. In this regard, the Guidelines (section 3.2) establish that: (1) uncertainty must not be resolved toward the least threatened option; (2) the plausible lower bound must be used when data gaps exist; (3) the decision must be precautionary and credible; and (4) the absence of recent data cannot be interpreted as stability.”
We recognise that there is concern that the Selvagem Grande population may be smaller than is reported in this assessment and that a precautionary approach should be taken when estimating minimum population sizes and maximum population reductions. We would like to reiterate that this assessment has already applied a precautionary approach for the population size and population reduction based on the available quantitative data. The minimum population size is derived as follows:
Selvagem Grande: minimum set to 1,064 pairs, calculated by assuming the rate of decline measured from 1995 (2,050 pairs) to 2013 (1,383 pairs) has continued.
Azores: 840 pairs (Monteiro et al. 1999, Equipa Atlas 2022, Pipa et al. 2024, OSPAR 2025).
Madeira: 129 pairs (minimum from 2009-2021 according to estimates for Selvagens and Madeira from Ramos 2013, SPNM 2015, 2016, Ramos et al. 2021, Equipa Atlas 2022, OSPAR 2025).
Desertas: minimum set to zero because there are no certain quantified estimates
Canary Islands: 158 pairs between 2019 and 2024 (SEO/BirdLife 2025)
Together, this gives a total minimum estimated population size of 2,191 pairs or 4,382 mature individuals. We recognise that the Selvagem Grande population may be lower than the estimate provided here. However, lacking any recent quantitative data, we have determined that projecting measured declines to 2025 provides the most precautionary and credible population size possible at this time. This is also considering that there are an unknown number of birds nesting on Selvagem Pequena that have not been considered in this population estimate.
While we recognise that some of these population estimates are not 2025 estimates, the absence of recent data is not interpreted as stability for this assessment. The stable trend for the Azores is based on reported trends (see Equipa Atlas 2022, Pipa et al. 2023, OSPAR 2025) not an absence of data. As mentioned, the trend for Selvagem Grande is considered to be declining at the same rate that was measured from 1995 to 2013. Although this trend may have changed, there is no quantitative data to derive the rate, and any assumptions on an accelerated rate of decline would therefore be arbitrary. Using the trend derived from available data, even if it is not current, is thought to be more credible than qualitative data and represents the ‘plausible lower bound’ according to the available information. Thus, the species does not meet the population size threshold (2,500 mature individuals) for Endangered under Criterion C1.
We recognise that extinction risk increases when a significant proportion of the global population is concentrated within a few declining subpopulations. This has been accounted for in this assessment, noting that the IUCN Guidelines stipulates the following when calculating reductions across multiple populations:
(4.5.4) – “All available data should be used to calculate a reduction as an average over all subpopulations, weighted by the estimated size of each subpopulation at the beginning of the period. Inferences regarding reductions should not be based on information for any single subpopulation (whether it is the fastest declining, most stable, largest or smallest)”.
(4.5.5) Using data from a few subpopulations – data should only be used from a single subpopulation “If there is no information on the rest of the subpopulations…” and “If it can be assumed that all (or all the large) subpopulations are declining at the same rate”.
Because there is sufficient information from the other populations, and the available information indicates they are not all declining at the same rate as Selvagem Grande, all populations are included in the reduction calculation, and it is weighted by the size of each population. Although the Selvagem Grande population is expected to decline by roughly 64% over three generations (worst-case scenario), the overall reduction is 46% because the Azores holds a significant number of mature individuals and is reportedly stable as outlined above. This scenario also includes a 70% decline in the Canary Islands population. We recognise that the Madeiran population may also be declining, but because this only has a small proportion of the total population, even a 100% reduction over three generations does not result in an overall reduction exceeding 50%. A survey providing updated quantitative population counts for Selvagem Grande (and ideally Selvagem Pequena) would allow a revaluation of this trend and the Categories and Criteria for this species can be reassessed at that time.
The final categorisation for this species has not changed. Barolo Shearwater is recommended to be listed as Vulnerable under Criteria A4b; C1.
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.