Roseate Tern
Scientific name: Sterna dougallii
Family laridae
- Phenology Mainland
- Passage migrant
- Phenology Madeira
- Summer breeder and passage migrant
- Phenology Azores
- Summer breeder and passage migrant
- IUCN Global Status
- Mainland Conservation Status
- Madeira Conservation Status
- Azores Conservation Status
Data
Maps
Occurrence | Spring
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Presentation
Distribution, movements and phenology
The Roseate Tern breeds in scattered locations across tropical and subtropical regions of the Atlantic, Indian and Pacific Oceans (Billerman et al. 2026). In Portugal, it breeds between April and July in the Azores and, to a lesser extent, on the island of Madeira. After breeding, birds that breed in the Azores appear to winter on the west coast of Africa or the coast of South America (Hays et al. 2002). On the Mainland, records occur mainly from August onwards, during the post-breeding migration of birds that nest in Northern Europe. This pattern is corroborated by individual tracking data from 26 birds from the United Kingdom and Ireland fitted with GLS devices. These data show that the Portuguese EEZ was used mainly during the non-breeding season, more specifically during the post-breeding migration.These birds were mainly found in the Mainland sub-area and east of Madeira.
Abundance and population trends
The global population has been estimated at between 200,000 and 220,000 individuals, of which 2,300 to 2,900 pairs breed in Europe. The largest colonies are concentrated in Ireland and the Azores (BirdLife International 2025).
In Madeira, breeding is irregular, occurring in a scattered manner across the island and not exceeding 50 pairs (Catry et al. 2010b; Equipa Atlas 2022). In the Azores, it breeds on all the islands, being most abundant on Flores, Graciosa, Terceira and Santa Maria. Annual censuses reveal considerable fluctuations, with a current estimate of around 535 to 1,068 pairs, indicating a slight decline (Equipa Atlas 2022). This pattern was also corroborated by the assessment presented in this work, which indicates that the species has not achieved Good Environmental Status for the abundance indicator. Regarding the situation on the Mainland and in Madeira, there is no information on abundance that would allow an assessment of its environmental status. Worthy of note is a count of 1,003 birds during the post-breeding migration in 2015, recorded from Cape Carvoeiro (Elmberg et al. 2020).
Ecology and habitat
The species nests in various coastal habitats, selecting sites close to shallow, sheltered feeding areas. Outside the breeding season, it uses estuaries and coastal waters, subsequently migrating to tropical coasts (BirdLife International 2025).
During the breeding season, it feeds near the colonies, catching small pelagic and mesopelagic fish in coastal and oceanic environments, and may be associated with the Common Tern (Ramos et al. 1998; Monticelli et al. 2006).
Threats and conservation
In the Azores, the main threat is predation of adults, eggs and chicks by introduced mammals, such as rats and cats (Lamelas-López et al. 2021). Breeding success is also affected by habitat destruction and degradation, including the presence of invasive plants and soil erosion caused by rabbits, disturbance due to human access to colonies, and predation by native species (Monteiro et al. 1996a; Cabral et al. 2005; Amaral et al. 2010; Neves et al. 2011b). In 2021, a new international plan for the conservation of the species was adopted (Piec & Dunn 2021). Various conservation measures are being implemented in some colonies, including the control of populations of gulls, rodents and cats (Lamelas-López et al. 2021) and habitat restoration (Bried et al. 2009a).
Ramos JA, Solá E, Monteiro LR & Ratcliffe N (1998). Prey delivered to roseate tern chicks in the Azores. Journal of Field Ornithology 69: 419-429. Bibliografia:
Piec D & Dunn EK (2021). International (East Atlantic) Species Action Plan for the Conservation of the roseate tern Sterna dougallii (2021-2030). Developed under the framework of the Roseate Tern LIFE Project (LIFE14 NAT/UK/000394). European Commission 2021. Bibliografia:
Neves VC, Panagiotakopoulos S & Ratcliffe N (2011b). Predation on roseate tern eggs by European starlings in the Azores. Arquipelago - Life and Marine Sciences 28: 15-23. Bibliografia:
Monticelli D, Ramos JA & Pereira J (2006). Habitat use and foraging success of roseate and common terns in flocks in the Azores. Ardeola 53(2): 293-306. Bibliografia:
Monteiro LR, Ramos JA, Furness RW (1996a). Past and present status and conservation of the seabirds breeding in the Azores Archipelago. Biological Conservation 78: 319–328. Bibliografia:
Lamelas-López L, Pietrzak M, Ferreira M & Neves VC (2021). Threats and conservation status of common and roseate terns Sterna hirundo/S. dougallii in the Azores: a case study for Terceira Island. Marine Ornithology 49: 301-309. Bibliografia:
Hays H, Neves V & Lima P (2002). Banded Roseate Terns from different continents trapped in the Azores. Journal of Field Ornithology 73: 180–184. Bibliografia:
Equipa Atlas (2022). III Atlas das Aves Nidificantes de Portugal (2016-2021). SPEA, ICNF, LabOr/UÉ, IFCN. Portugal. Bibliografia:
Elmberg J, Hirschfeld E, Cardoso H & Hessel R (2020). Seabird migration at Cabo Carvoeiro (Peniche, Portugal) in autumn 2015. Marine Ornithology 48: 231-244. Bibliografia:
Bried J, Magalhães MC, Bolton M, Neves VC, Bell E, Pereira JC, Aguiar L, Monteiro LR & Santos RS (2009a). Seabird habitat restoration on Praia Islet, Azores Archipelago. Ecological Restoration 27(1): 27–36. Bibliografia:
BirdLife International (2025). IUCN Red List for birds. Downloaded from https://datazone.birdlife.org on 30.11.2025. Bibliografia:
Billerman SM, Keeney BL, Kirwan GM, Medrano F, Sly ND & Smith MG (eds.) (2026). Birds of the World. Cornell Laboratory of Ornithology, Ithaca, NY, USA. Bibliografia:
Amaral JJS, Almeida S, Sequeira M & Neves VC (2010). Black rat Rattus rattus eradication by trapping allows recovery of breeding roseate tern Sterna dougallii and common tern S. hirundo populations on Feno Islet, the Azores, Portugal. Conservation Evidence 7: 16-20. Bibliografia:
Cabral MJ (coord.), Almeida J, Almeida PR, Dellinger T, Ferrand de Almeida N, Oliveira ME, Palmeirim JM, Queiroz AI, L Rogado L & Santos-Reis M (eds.) (2005). Livro Vermelho dos Vertebrados de Portugal. Instituto da Conservação da Natureza, Lisboa Bibliografia:
Catry P, Geraldes P, Pio JP & Almeida A (2010b). Aves marinhas da Selvagem Pequena e do Ilhéu de Fora: censos e notas, com destaque para a dieta da gaivota-de-patas-amarelas. Airo 20: 29-35 Data:
Redfern C (2019). Dataset 1626: Roseate Tern, Sterna dougallii, Geolocator (GLS), Coquet, England, United Kingdom, 2018–2019. BirdLife International Seabird Tracking Database. Downloaded from https://data.seabirdtracking.org/dataset/1626/ on 30.11.2025. Data:
Redfern C (2018a). Dataset 1627: Roseate Tern, Sterna dougallii, Geolocator (GLS), Rockabill, Rockabill, Ireland, 2017–2018. BirdLife International Seabird Tracking Database. Downloaded from https://data.seabirdtracking.org/dataset/1627/ on 30.11.2025. Glossário:
The process of recovering degraded ecosystems with the aim of restoring their original structure and function. Glossário:
Population management of invasive species without total elimination. Glossário:
A species or parameter that reflects the state of an ecosystem or environmental changes. Glossário:
Monitoring the movements of individuals using tracking devices. Glossário:
A concept defined under the Marine Strategy Framework Directive (MSFD), referring to the condition of the elements of the marine environment, including birds. It aims to assess whether ecosystems are healthy, balanced and capable of supporting ecological functions and human uses in a sustainable manner. The ultimate goal is for the components and ecosystems to achieve Good Environmental Status. Glossário:
Under the United Nations Convention on the Law of the Sea, coastal states are entitled to declare an EEZ comprising maritime area beyond their territorial waters. The national EEZ is delimited by an imaginary line situated 200 nautical miles from the coast, separating national waters from international or shared waters. Within its EEZ, each state has rights such as the exploitation of marine resources, the conduct of scientific research and the regulation of fishing by foreign vessels. Glossário:
Referring to the period following breeding. Glossário:
The area or environment where organisms that do not depend on the seafloor normally live. It is the typical ecological environment of open ocean waters. The pelagic ecosystem does not include only the open sea; it also comprises the waters covering the continental shelf. The pelagic zone begins below the influence of tides and extends into the open ocean, at depths ranging from a few tens of metres to approximately 6,000 metres, and is divided into different layers. Glossário:
A marine organism living in the water column generally between 200 and 1,000 metres in depth. Glossário:
A small device attached to birds to study their large-scale movements (usually migration), which works by recording light intensity (from which the duration of night and the local midday time are estimated, and consequently the latitude and longitude on each day). Glossário:
A term generally applied to a species introduced deliberately or accidentally into a specific location or region outside its original range. Depending on its adaptation to the new environment, an introduced species may or may not become naturalised and proliferate.
