Status Assessment 2025 - Macaronesian shearwater
Since the first status assessment, there have been considerable improvements in the monitoring of Macaronesian shearwater in the Wider Atlantic (Region V), despite population size being assumed to be far below the numbers found in the past. In the Azores, the situation has been apparently stable since the last assessment. In the neighbouring archipelagos, outside of the OSPAR maritime area, however, the species is likely not doing so well. No information is available regarding the non-breeding population.
| Assessment of status | Distribution | Population size | Demographics, e.g. productivity | Previous OSPAR status assessment | Status (overall assessment) | |
|---|---|---|---|---|---|---|
Region | I | NA | ||||
| II | NA | |||||
| III | NA | |||||
| IV | ? | ? | ? | ○ | ? | |
| V | ←→3 | ←→5 | ? | ● | ? | |
| Outside | ←→3 | ↓5 | ↓5 | ○ | ? | |
Assessment of key pressures | Predation | Introduction of non-indigenous species and translocations | Light pollution | Marine litter | Perturbation by human presence | Oil pollution | Outside the OSPAR area | Overall threat or impact | |
|---|---|---|---|---|---|---|---|---|---|
Region | I | NA | |||||||
| II | |||||||||
| III | |||||||||
| IV | NA | NA | ? | ? | NA | ? | ? | ||
| V | ←→5 | ←→5 | ←→5 | ? | ←→5 | ? | ↑3 | ||
Explanation to table:
Distribution, Population size, Condition
Trends in status (since the assessment in the background document)
↓ decreasing trend or deterioration of the criterion assessed
↑ increasing trend or improvement in the criterion assessed
←→ no change observed in the criterion assessed
? trend unknown in the criterion assessed
Previous status assessment: If in QSR 2010 then enter Regions where species occurs ( ○) and has been recognised by OSPAR to be threatened and/or declining (● ) based on Chapter 10 Table 10.1 and Table 10.2 . If a more recent status assessment is available, then enter ‘poor’/’good’
Status*(overall assessment)
red – poor
green – good
blue ? – status unknown
NA- Not Applicable
*applied to assessments of status of the feature or of a criterion, as defined by the assessment values used in the QSR 2023 or by expert judgement.
Key Pressure
↓ key pressures and human activities reducing
↑ key pressures and human activities increasing
←→ no change in key pressures and human activities
? Change in pressure and human activities uncertain
Threats or impacts (overall assessment)
red – significant threat or impact;
green–no evidence of a significant threat or impact
Blue cells – insufficient information available
NA – not applicable
Types of assessment:
1 – direct data driven,
2 – indirect data driven,
3 – third party assessment close-geographic match,
4 - third party assessment partial-geographic match
5 – expert judgement.
Confidence
Medium
Background Information
Year added to OSPAR list: 2003 (OSPAR 2008)
- The original evaluation of Macaronesian shearwater against the Texel-Faial criteria referred to regional importance, decline and sensitivity, with information also provided on threats.
- Last status assessment: 2009. OSPAR (2009) assessment was conducted shortly after the species case report. Population trends for this species in the Azores were poorly documented but there was strong circumstantial evidence indicating that most areas of the Azores had been rendered unsuitable breeding habitat due to the introduction of rats and cats by humans, and the species was considered rare.
Geographical Range and Distribution
Information on the distribution of Macaronesian shearwater has undergone considerable improvement since the last assessment. The most notable was regarding the information about distribution at sea. Despite relying on a small sample size of tracked birds, adults from the Azores but also from Selvagens Archipelago and Porto Santo (in Madeira Archipelago) use the Wider Alantic (OSPAR Region V) during both the breeding and non-breeding seasons (Figure 1). Additionally, birds from Selvagens and Porto Santo also make use of the Bay of Biscay and Iberian Coast (Region IV) throughout both seasons. Regarding distribution of breeding colonies, the species occurs across all Azorean islands (in Region V), as well as in the neighbouring Madeira (Madeira Island, Porto Santo and Desertas), Selvagens and Canary (all islands except La Graciosa and Gran Canaria) archipelagos.
Method of assessment: 2a and b – sources: Neves et al., 2012, Bécares et al., 2016; Fagundes et al., 2016; Saavedra et al., 2018; Pipa et al., 2021; Equipa Atlas, 2022; SEO/BirdLife, 2022.
Figure 1: Macaronesian distribution range at the OSPAR area, combining several information sources.
Population/Abundance
In the Azores (in Region V), current estimates are similar to the historic numbers pointing to a stable population (Table 1; Pipa et al., 2021). However, the largest known colony of Macaronesian shearwater from Macaronesia, situated on Selvagens, shows a strong decline (Saavedra et al., 2018). On the other hand, complete information on population size and trends is still lacking for the Canary Islands. Nevertheless, evidence suggests a severe decline in some colonies in a near future, with the potential for their imminent disappearance (Rodríguezet al., 2012, Bécares et al., 2016). No information on the population size during the non-breeding period is available.
| Baseline | Current | Trend | |||
| Period | No. pairs | Period | No. pairs | ||
| OSPAR Region V (Azores) | 1996-1998 | 840-1530 | 2018-2022 | 920-1420 | ←→ |
| Madeira Archipelago | 2013-2021 | 144-183 | ? | ||
| Selvagens | 1994 | 2050-4900 | 2013 | 1383-3689 | ↓ |
| Canary Islands | 1987 | 400 | 2016 | >91-296 | ? |
Method of assessment: 2b and d – sources: Monteiro et al., 1999, Bécares et al., 2016, Saavedra et al., 2018, Pipa et al., 2021, Equipa Atlas, 2022, SEO/BirdLife, 2022, I. Fagundes comm. Pers.
Condition
No historical information is available about the condition of Macaronesian shearwater breeding populations in OSPAR Region V. Recently, information on breeding success is being collected in the frame of the Marine Strategy Framework Directive monitoring plan for Azores (Saavedra et al., 2018). Vila and Praia colonies showed marked oscillations in the estimates of breeding productivity between 2018 and 2022 (Figure 2; Atchoi 2021; Pipa et al., 2024). Outside the OSPAR area, recent analyses showed a strong relationship between breeding success and nest site characteristics, hilighting a negative effect of climactic stochasticity events (Fagundes et al., 2016).
Method of assessment: 2a and d – sources: Atchoi, 2021; Pipa et al., 2024.
Figure 2: Breeding success of Macaronesian shearwater in Vila (blue) and Praia (orange) islets, located in Azores (Region V). No historical information is available for the species.
Threats and Impacts
Predation by non-indigenous mammal species and Yellow-legged gulls remains as the major threat at its breeding sites, particularly on the main Azorean Islands. However, the islets inhabited by the species are mammal free. Additionally, the Yellow-legged gull population is declining in most of the Azorean islands (Oliveira et al., 2013). Light pollution, ingestion of marine litter and perturbation by human presence are still considered relevant threats to the species in the Azores but also on all other Macaronesia islands (Saavedra et al., 2018). Additional threats include climate change and extreme weather conditions. At sea, individuals are also susceptible to oil pollution whilst feeding. Macaronesian shearwaters generally do not follow ships, and there is no evidence they are at risk from fisheries bycatch (Cooperet al., 2003).
Measures that address key pressures from human activities or conserve the species/habitat
Macaronesian shearwater is protected by law in all the countries within OSPAR area where the species occur. In Region V, some breeding colonies and foraging areas at sea are located within the oceanic (15 areas in Azores Marine Park) and coastal (9 Island Natural Parks) Marine Protected Areas. Outside OSPAR area, breeding colonies are located within Special Protection Areas (SPA), some of them protecting foraging areas, including Madeira/Selvagens in Portugal (4) and Canary Islands in Spain (20). The OSPAR’s Regional Action Plan for Marine Birds in the North-East Atlantic (2024-2030) was published by 2024. The species was identified as an indicator under the MSFD framework in Azores, Madeira and Canary islands. Portugal (Madeira) published a regional action plan for 14 seabird species, including Macaronesian shearwater (SPNM, 2015).
Conclusion (including management considerations)
Since the first status assessment, there has been considerable improvements towards the monitoring and conservation of Little shearwater, despite the need to maintain monitoring in the long-term and on a more frequent basis, namely the census of the breeding population from the entire Azores Archipelago. Also, outside OSPAR area, namely on Madeira, Selvagnes and Canary islands, secure or increase monitoring effort of colonies is advisable.
The species breeds in mammal predator free islets and islands at inaccessible cliffs for humans. Population trend is likely stable in Azores, but a strong decrease was found in Selvagens, the largest known colony in Macaronesia. More comprehensive information is needed for Canary and Madeira archipelagos.
Predation by non-indigenous species is still considered as the most problematic threat in and outside the OSPAR area, confining the species to small islets and inaccessible cliffs. Little has been done regarding the management of non-indigenous species on the main Azorean islands.
The information on the condition of the breeding population is improving, as well as information on the wintering areas.
A re-assessment might be done in a medium-term cycle i.e., 5 years, based on the anticipated availability of data on condition and population size.
Knowledge gaps
Lack of long-term monitoring data to inform metapopulation management at the Macaronesia subregion, including OSPAR Region V, is hindering a comprehensive assessment. Acoustic recording on a regular basis could be used to census the breeding population. Demographic parameters should be recorded at the key breeding areas.
Knowledge gaps on the effect of non-indigenous mammal predators on the main islands, and the effects of light pollution on adult and immature survival are among the top priority limitations which need to be addressed.
Method of assessment:
- Assessment derived from third party assessment.
Assessment is based upon:
- complete survey or a statistically robust estimate (e.g. a dedicated mapping or survey or a robust predictive model with representative sample of occurrence data, calibration and satisfactory evaluation of its predictive performance using good data on environmental conditions across entire species range);
- based mainly on extrapolation from a limited amount of data (e.g. other predictive models or extrapolation using less complete sample of occurrence and environmental data);
- insufficient or no data available.
Atchoi, E. 2021. Relatório Final LuMinAves – FRCT. Okeanos-UAç, Horta, Azores.
Bécares, J., Gil-Velasco, M. y Aguilar, N. 2016. Canarias con la Mar II. Conservación de cetáceos y Aves marinas en Canarias (Memoria Técnica). Informe de GIC-ULL a la Fundación Biodiversidad- MAGRAMA.
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OSPAR. 2008. Case Reports for the OSPAR List of Threatened and/or Declining Species and Habitats:Puffinus assimilis baroli – Little shearwater. OSPAR Commission. London. p 41-42. https://www.ospar.org/site/assets/files/44255/little_shearwater.pdf
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Pipa et al., 2021. Seabird Macaronesian Report (SMS) Azores (not published).
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SPNM. 2015. Planos de Ação das 14 espécies alvo do projeto LIFE ILHÉUS DO PORTO SANTO (LIFE09 NAT/PT/000041). Serviço do Parque Natural da Madeira (SPNM). https://ifcn.madeira.gov.pt/images/Doc_Artigos/Biodiversidade/Projetos/lips/Relatorios/planosacao14esp.pdf
Sheet reference:
BDC 2025/Macaronesian_shearwater