Roseate Tern
Sterna dougallii
Number Of Mature
Individuals (Regional)
328
Regional
Population Trend
Decreasing
2025
Regional Category
Vulnerable
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CONTENTSOverview
Names
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IOC English Name: |
Roseate Tern |
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SA & IOC Scientific Name: |
Sterna dougallii |
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BirdLife International Taxonomy (scientific name): |
Sterna dougallii |
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Order: |
CHARADRIIFORMES |
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Family: |
Laridae |
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Species name author: |
Montagu 1813 |
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Afrikaans: |
Rooiborssterretjie |
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Sesotho (South Africa): |
Lepheulane la sefubapinki |
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Sesotho (Lesotho): |
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Siswati: |
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Zulu: |
insukakudesisila |
Current Assessment Status
|
2025 Regional Category [Criteria] |
VU [D1] |
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2024 Global Category [Criteria] |
LC (BirdLife International 2018) |
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Population size (Regional) |
c. 164 breeding pairs |
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Population size (Global) |
c. 200 000 – 220 000 (Wetlands International 2015) |
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Distribution size (EOO) (Regional) km2 |
Unknown |
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Distribution size (EOO) (Global) km2 |
184 000 000 (breeding/resident) |
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Distribution size (AOO) (Regional) km2 |
0.28 (breeding; combined size of Bird and Dyer islands) |
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Generation time |
8.36 years (Bird et al. 2020) |
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Status change reason |
Improved Knowledge |
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Migrant (in the region) |
Full Migrant |
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Regional endemic |
No |
Historic Listing Information
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2000 Regional Status |
EN [B1+3d; C2a] |
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2015 Regional Status |
EN [B2ac(iv); C2b; D] |
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Status change reason (if applicable) |
No change |
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2015 Population size (Regional) |
<250 mature individuals |
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2015 Global Status |
LC |
Reason for Inclusion
Reason for Inclusion in the Assessment
This species breeds in the region. It was assessed as regionally Endangered in 2000 and 2015 (Underhill 2000, Hagen 2015).
Category Justification
Category Justification
The South African population of Roseate Tern Sterna dougallii breeds at a few small island colonies, and numbers less than 1000 mature individuals, satisfying the criteria for regionally Vulnerable under Criterion D. Although the tiny regional Area of Occupancy meets the threshold for Critically Endangered the regional population is considered stable, hence the subcriteria for Criterion B are not met.
Population Justification
The global population is estimated to be between 200 000 and 220 000 individuals (Wetlands International 2015). The regional population has been estimated to variably range between at least 27 and 310 breeding pairs from 1975 and 2017 (Tree et al. 2019). The most recent regional population estimate was c. 164 pairs in 2017 (Tree et al. 2019). Confidence in this regional population estimate is medium.
Trend Justification
The global population trend is uncertain, as some subpopulations are decreasing, while others are increasing or stable (BirdLife International 2018). Numbers of Roseate Terns breeding in South Africa have been low since population counts began in 1967. Breeding was recorded at Cape Recife in 1967 (39 pairs) and 1968 (71 pairs) but only roosting birds have been recorded since then. Low numbers of breeding pairs have been recorded at Dyer Island since 1971, ranging from no breeding to 54 pairs, with no clear upward or downward trend. At St Croix Island, 118 – 139 breeding pairs were recorded in 1977. Until 2003, counts have been erratic, and in some years only the presence of breeding birds has been recorded. In 2003, there were 30 breeding pairs at St Croix Island, which then increased to 58 in 2007 followed by a decrease to 25 in 2008 (Crawford et al. 2012). No Roseate Terns have been recorded breeding at this island since 2009. The species was first recorded breeding at Bird Island in 1977 and the first count (130 pairs) occurred in 1986. This colony reached a peak of 300 breeding pairs in 2010 (Crawford et al. 2024) and has shown high interannual variability (Tree et al. 2019). The population is prone to a considerable amount of fluctuation although over a three-generation period, the population trend is stable. Confidence in this regional trend estimate is medium.
Biology & Ecology
Taxonomy
Globally, five subspecies are recognised (Gill et al. 2023). South African birds are currently classified with the nominate S. d. dougallii but further research is needed to clarify the complex subspecific taxonomy of this species (Tree 2005).
Identification
33–38 cm, 120 g. Sexes alike. Cap black. Wings, rump and tail pale silver-grey. Outer 3–4 primaries darken with wear. Elongated outer rectrices extend well past wings. Underparts white with pale pink tinge. Bill long and slender with slightly drooping tip; black before breeding, becoming pinkish-red with a black tip during incubation, and returning to black after the young fledge. Non-breeding adults have white foreheads and are less pink below; bill black and legs brownish-orange. Immatures are similar but show a dark bar on the wing coverts. Pink breast develops at one year. Juveniles show heavily mottling and scalloping with black bills and legs that become pinkish during their first year. Easily confused with other tern species (Tree 2005).
Distribution
Roseate Terns have a large, fragmented global range, breeding in the western and eastern North Atlantic Ocean (North America, Azores, western Europe), from the Arabian Peninsula south to East Africa, Madagascar and South Africa, east to the Indian subcontinent, East Indies and into the western Pacific Ocean and south to Australia (Gochfeld 1983). Within the region, it now breeds at only two sites – Bird and Dyer islands – after breeding ceased at St. Croix in 2009 (Tree et al. 2019). It has also been recorded breeding at Cape Recife (Randall and Randall 1980, Randall et al. 1991) where large pre-and post-breeding assemblages occur (Tree 2005). Most birds are probably resident within the region with neither North Atlantic nor Indian Ocean birds known to migrate to southern Africa. Roseate Terns are present on their breeding islands from May to October but are present along the coast year-round (Tree 2005). The species breeds in two IBAs, both of which are protected, namely Algoa Bay Islands: Addo Elephant National Park (IBA SA095) and Dyer Island Nature Reserve (IBA SA120) (Underhill 2000).
Ecology
The species nests in various habitats including sand dunes, sand spits, shingle beaches, reefs, saltmarshes, and rocky, sandy, or coral islands (del Hoyo et al. 1996, Snow and Perrins 1998). It prefers densely vegetated sites in temperate regions but opts for sparsely vegetated sites in tropical areas (del Hoyo et al. 1996). Additionally, it favours nest sites near clear, shallow, sandy fishing grounds, particularly in tidal bays and sheltered inshore waters (Snow and Perrins 1998). Low rocky headlands, and less often beaches and sandbanks, are preferred as roosting sites (Tree 2005). Roseate Terns feed on small pelagic fish caught by plunge diving; fishing mostly occurs within 2 km of the colony, often in association with other seabirds (Randall et al. 1991). A generation length of 8.36 years is provided by (Bird et al. 2020).
Threats & Conservation
Threats
Breeding Roseate Terns are vulnerable to disturbance as they do not return to their nests immediately when displaced (Underhill 2000), thus leaving eggs and chicks vulnerable to predation by Kelp Gulls Larus dominicanus. Chicks are vulnerable to hypothermia during cold, wet weather (Randall et al. 1991). In West Africa, decreases have been attributed to hunting (BirdLife International 2018).
Conservation Measures Underway
No species-specific conservation measures are currently underway in South Africa. Breeding sites on Bird and Dyer islands are protected as nature reserves. A control programme aimed at controlling the numbers of the predatory Kelp Gull is ongoing at Bird Island, which is likely to benefit this species as well as other seabirds. The species is protected in terms of South Africa’s Sea Birds and Seals Protection Act, No. 46 of 1973. Globally, efforts are underway to improve breeding habitat by constructing artificial nesting sites and nest boxes, vegetation management and flood control (BirdLife International 2018).
Conservation Measures Proposed
Disturbance at both breeding and roosting sites should be limited. A full study of what conservation measures will be most beneficial to Roseate Terns should also be conducted.
Research Priorities and Questions
- Increasing the knowledge on post-breeding movements of Roseate Terns. See Tree et al. (2019).
- An investigation should be made into whether improving vegetation cover or providing artificial nests will improve breeding success as it has done elsewhere – e.g. Burke et al. (2022).
- The impact of predation by Kelp Gulls on eggs and chicks should be quantified.
Contributors & References
Assessor/s
Philip A. Whittington
Reviewer/s
Maëlle Connan
References
Bird JP, Martin R, Akçakaya HR, Gilroy J, Burfield IJ, Garnett ST, Symes A, Taylor J, Şekercioğlu ÇH, Butchart SH. 2020. Generation lengths of the world’s birds and their implications for extinction risk. Conservation Biology 34: 1252–1261.
BirdLife International. 2018. Sterna dougallii. The IUCN Red List of Threatened Species 2018: e.T22694601A132260491. Available: https://dx.doi.org/10.2305/IUCN.UK.2018-2.RLTS.T22694601A132260491.en. [Accessed on 7 August 2023].
Burke B, O’Connell DP, Kinchin-Smith D, Sealy S, Newton SF. 2022. Nestboxes augment seabird breeding performance in a high-density colony: Insight from 15 years of monitoring data. Ecological Solutions and Evidence 3: e12171.
Crawford RJM, Dyer BM, Kotze PGH, McCue S, Meÿer MA, Upfold L, Makhado AB (eds). 2012. Status of seabirds breeding in South Africa in 2011. Cape Town, South Africa: Oceans and Coasts, Department of Environmental Affairs.
Crawford RJM, Whittington PA, Dyer BM, Makhado AB. 2024. Numbers, trends, status and conservation of Roseate Tern (Sterna dougallii) in South Africa. In: Makhado AB, Amaro A, Crawford RJM, Gottlieb TR, Morais M, Mwaala DN, Nghimwatya L, Seakamela M, Tom DB, Whittington PA, Witteveen M (eds), Atlas of marine turtles, seabirds, and seals in the Benguela Current and adjacent regions. Population sizes and trends, conservation status, and Important Bird and Biodiversity Areas for breeding. Benguela Current Convention, Swakopmund, Namibia and Department of Forestry, Fisheries and the Environment, Cape Town, South Africa.
del Hoyo J, Elliott A, Sargatal J. 1996. Handbook of the Birds of the World, vol. 3: Hoatzin to Auks. Lynx Edicions, Barcelona, Spain.
Gill F, Donsker D, Rasmussen P (eds). 2023. IOC World Bird List version 13.1. DOI: 10.14344/IOC.ML.13.1.
Gochfeld M. 1983. The Roseate Tern: world distribution and status of a threatened species. Biological Conservation 25: 103–125.
Hagen C. 2015. Roseate Tern. In: Taylor M, Peacock F, Wanless R (eds), The Eskom Red Data Book of Birds of South Africa, Lesotho and Swaziland. Johannesburg, South Africa: BirdLife South Africa. pp 169–170.
Randall RM, Randall BM. 1980. Status and distribution of the Roseate Tern in South Africa. Ostrich 51: 14–20.
Randall RM, Randall BM, Ralfe M. 1991. Roseate Terns in South Africa: population size, revision of previous estimate and conservation. Bontebok 7: 1–6.
Snow, DW, Perrins CM. 1998. The Birds of the Western Palearctic, Volume 1: Non-Passerines. Oxford University Press, Oxford.
Tree AJ. 2005. Roseate Tern Sterna dougallii. In: Hockey PAR, Dean WRJ, Ryan PG (eds), Roberts – Birds of Southern Africa, 7th Edn. Cape Town, South Africa: The Trustees of the John Voelcker Bird Book Fund. pp 456–458.
Tree AJ, Connan M, Whittington PA. 2019. Roseate Terns Sterna dougallii on the southeast coast of South Africa: information on moult and migratory status. Ostrich 90(4): 303–313.
Underhill LG. 2000. Roseate Tern Sterna dougalli. In: Barnes KN (ed), The Eskom Red Data Book of Birds of South Africa, Lesotho and Swaziland. Johannesburg, South Africa: BirdLife South Africa. pp 43–45.
Wetlands International. 2015. Waterbird Population Estimates. Available at: wpe.wetlands.org.
Citation
Whittington PA 2025. Roseate Tern. In: Lee ATK, Rose S, Banda S, Bezeng SB, Maphalala MI, Maphisa DH, Smit-Robinson H (eds), The 2025 Red Data Book of Birds of South Africa, Lesotho and Eswatini. Johannesburg, South Africa: BirdLife South Africa. Available at: https://www.birdlife.org.za/red-list/roseate-tern/
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