13 thoughts on “Damara Tern (Sternula balaenarum)”
Although I agree that looking to the breeding bird development is probably the best way to monitor this population we include this species also in our East Atlantic Flyway assessment reports based on non-breeding January IWC counts. The couns confirm the small population size and tendency to decline.
Fully endorse this suggested status change, for all the reasons laid out above. The previous listing was clearly erroneous, and the sooner it is corrected, the sooner a more realistic threat assessment can be invoked to influence directly relevant conservation and development decisions.
Comments on RED LIST STATUS: DAMARA TERN (Sternula Balaenarum)
By Jean-Paul ROUX
I fully support the reassessment of this species and the proposed change from Vulnerable (or Least Concern which in my view was a mistake in 2020) to Endangered under the criteria C1+2a(ii) as detailed in this document.
My additional preliminary comments are:
A) Under the heading Specific Questions: Do you have any 2026 colony counts or estimates of the 2026 population size?
The Elizabeth Bay colony in southern Namibia (approximately 26.917 S, 15.247 E and adjacent to an extensive coastal diamond mine), which had been surveyed in previous years including in Braby 2011 and in Simmons Braby and Braby 2015*) and noted as declining, was thoroughly re-surveyed on 24 January 2026, and no breeding activity and no bird presence was detected. This leads to the conclusion that this colony is now probably extinct (Dr J Kemper and Dr M Lemerle pers com). This new information confirms the previously assumed declining trend of the population.
It should be noted that due to the difficulty of accessing remote locations in the coastal Namib desert, as well as due to access restrictions due to the Diamond Act regulations for the last century, some potential suitable breeding habitats for Damara terns have been poorly surveyed to date. A few additional breeding localities of this species are suspected to occur within the Tsau//Khaeb National Park in previously unsurveyed areas (so they are not suspected to be recently established, but rather undiscovered to date). Such potential additional breeding localities are unlikely to support large numbers of breeding pairs and are therefore not expected to have consequences for the present assessment, and in particular for the overall declining population trend. However, if new localities are confirmed and assessed by further monitoring efforts, they should be included in future conservation priorities and in threat assessments related to proposed large-scale industrial developments in the region.
*This important reference which gives detailed account and size and trend estimates of all known Damara tern colonies in Namibia at the time has been omitted from the document: Simmons RE, Braby RJ, Braby SJ. 2015. Damara Tern Sternula balaenarum (Sterna balaenarum). Pp 91-95 in: Simmons RE, Brown CJ and Kemper J (Eds). Birds to watch in Namibia: Red, rare and Endemic species. Ministry of Environment and Tourism and Namibia Nature Foundation. Windhoek, Namibia.
B) In Annex 1, under the heading Subpopulation structure: The justification: “This species is migratory and change breeding colony between years, and therefore likely occurs as a single subpopulation” Should be considerably watered down for several reasons:
a. While there are a few examples of marked birds changing breeding colony between years, this was attributed to excessive disturbance on the original colony (RJ Braby pers. com.) and the change of colony was extremely local (< 10 km). At the same time there is ample evidence from many more marked birds that they are in fact very faithful to their breeding sites. So, this argument by itself does not make it likely that the species is a single subpopulation.
b. The recent results from Allport et al 2022 show that the rather outlying south-eastern population (in the Eastern Cape Province) migrates along the East coast of southern Africa (instead of tropical western Africa)… As this breeding population is distant (by more than 500 km) from the West coast birds and migrates through a different pathway to a different wintering destination it is probable that it might constitute a distinct subpopulation from the rest of the species. This considerably weakens the assumption that the species likely occurs as a single subpopulation as stated.
c. Similarly, the small Western Cape Province population being distant by more than 700 km from the rest of the west coast colonies is also likely to be an isolated subpopulation.
d. Further recent evidence from studies being currently conducted in Namibia suggests that the species might actually be fragmented at an even finer scale (including between breeding sites, migrants vs non migrant subpopulations, timing of breeding (including winter breeding) etc…) e.g. Roux et al. 2025.**
** Roux JP, Boorman M, Braby J, Braby RJ. Fijn RC. 2025, A new longevity record for the Damara tern Sternula balaenarum. Namibian Journal of Environment 10, B-12
C) Still in Annex 1, the Extent of Occurrence (EOO) is given as 945 000 Km2. As this criterion is calculated using the minimum convex polygon method and seems to include all subpopulations (including that of the Eastern Cape province) it should be noted that this huge area encompasses a large portion of southern Africa including places up to about 500 km inland and the western edge of the Kalahari Desert. This is therefore very unrealistic for a strictly coastal bird. As this criterion was used in the previous assessment to justify a Least Concern status, this caveat should be noted and emphasized in the text.
Further, the EOO of the Northern Cape Province, Namibian and Angolan part of the population (which constitutes >95% of the species) could reasonably be estimated at about 15 000 Km2 which is only about 1.6% of the present estimate. Again, it should be noted that this criterion, as presently calculated, is giving an extremely misleading and unrealistic result when applied to the Damara Tern.
I am in full agreement with the proposed status change and with the justification behind it. I also support Dr. Roux’s additional arguments that are provided here as a set of comments. Especially with a surge in planned coastal (terrestrial and marine) developments throughout the Damara Tern’s breeding range, including in protected areas, it is essential that the previously incorrect listing is rectified to ensure appropriate decision-making.
As someone who wrote the PhD thesis “Biology and Conservation of the Damara Tern” (2011), and published multiple papers out of the thesis, and someone who has been part of monitoring Damara Terns, along with my parents (who have monitored since 1980s), since the 1990s, along the entire coastline of Namibia from the Skeleton coast down to the Sperrgebiet, I fully endorse the proposal set forward, as well as those comments made by Dr Roux above. The proposed change to Endangered reflects the reality of the species situation, and will allow conservation efforts to adequately address this.
I strongly agree with the proposal to categorize it as an endangered species. During our IWC, 2026, this species was not sighted, which may indicate a serious decline in its population.
I also fully endorse the proposed change of the status of Damara Tern to Endangered. As Dr Roux points out there are large gaps between breeding populations in Namibia, the very small Western Cape population and that in the Eastern Cape of South Africa.
Based on the reduction in numbers over three generations the regional assessment was close to that of Critically Endangered and the 2015 Regional Assessment was considered to be Critically Endangered (Simmons, R.E. 2015. Damara Tern Sterna balaenarum. In The Eskom Red Data Book of Birds of South Africa, Lesotho and Swaziland. Taylor, M.R., Peacock, F. and Wanless, R.W. (eds). BirdLife South Africa, Johannesburg, South Africa. pp 52-54.
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 22 May 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 22 May 2026, when discussions will re-open.
Many thanks to all contributors above for their comments and support on this proposal. We will ensure that relevant information is captured where appropriate in the final assessment.
We will ensure that the possible extirpation of the Elizabeth Bay colony is captured in the final assessment and will ensure the Simmons et al. 2015 reference is included. We have responded to specific points below:
B) subpopulations:
The information provided is helpful. Please note that the IUCN’s definition of a single subpopulation requires only that “one successful migrant individual per year or less” moves between areas; this definition may differ from other biological or ecological definitions of a subpopulation. Nonetheless, on reflection of the comments, it may be more accurate to suggest a range of 1-3 subpopulations (or more). The information provided in the reference and the comment will be considered and the number of subpopulations will be revised. Please note that the species may no longer qualify as Endangered under Criterion C2a(ii) if it occurs in more than one subpopulation. It will still qualify as Endangered under Criterion C1.
C) EOO:
We recognise that the current EOO includes areas that do not contain suitable habitat for this species. The IUCN Guidelines discourages the use of methods other than a Minimum Convex Polygon when calculating the EOO: “for assessments of criterion B1, exclusion of areas forming discontinuities or disjunctions from estimates of EOO is strongly discouraged.” The purpose of the EOO is to capture the spatial spread of the areas currently occupied by the species and therefore measure the degree to which risks from threatening factors are spread spatially across the species’ distribution, rather than capturing the actual area where the species occurs which is represented by the Area of Occupancy. The Area of Occupancy has not been calculated for this proposal because it is inferred to be larger than 2,000 km2 (the threshold for listing as threatened under Criterion B2), but data on this would be helpful. As such, we will not be revising the EOO to ensure consistency with the IUCN Guidelines and other BirdLife Red List assessments.
Based on available information, our preliminary proposal for the 2026 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 31 May 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 in November 2026, following further checking of information relevant to the assessments by both BirdLife and IUCN.
I appreciate that IUCN’s protocols for calculating and using EOO (by minimum convex polygon) as a measure of spatial spread in species assessments should not be changed. However, it should be explicitly acknowledged in the text as being an unrealistic measure for the assessment of this species – as per Dr. Roux’s original arguments. The reason for this is that the unrealistically inflated EOO was the main argument used in the 2020 revision leading to the erroneous “Least Concern” classification.
With regard to subpopulations, I think at least two should be considered. The birds breeding in South Africa’s Eastern Cape are now spending the non-breeding period in Mozambique. This has been confirmed from sightings of leg-flagged birds from the Eastern Cape (see Allport et al. 2022, Martin et al. in press). About 100 birds have been recorded in Mozambique in the Austral winter so the bulk of the population that breeds in Namibia presumably still migrates to the Gulf of Guinea, West Africa.
Martin, A.P, Whittington, P.A., Dyer, B.M., Crawford, R.J.M.C. & Makhado, A.B. In press. Numbers, trends, status, movement and conservation of Damara Terns (Sternula balaenarum) 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.
I fully endorse the proposed change in status and support comments and arguments made by Dr. Jessica Kemper and Dr. Jean-Paul Roux. The sooner the classification is changed from the erroneous “Least Concern” to “Endangered” the better for the improved long-term conservation of the species.
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 8 June 2026.
Although I agree that looking to the breeding bird development is probably the best way to monitor this population we include this species also in our East Atlantic Flyway assessment reports based on non-breeding January IWC counts. The couns confirm the small population size and tendency to decline.
https://flyway.waddensea-worldheritage.org/news/new-report-shows-current-trends-migratory-waterbird-populations-east-atlantic-flyway.
Fully endorse this suggested status change, for all the reasons laid out above. The previous listing was clearly erroneous, and the sooner it is corrected, the sooner a more realistic threat assessment can be invoked to influence directly relevant conservation and development decisions.
Comments on RED LIST STATUS: DAMARA TERN (Sternula Balaenarum)
By Jean-Paul ROUX
I fully support the reassessment of this species and the proposed change from Vulnerable (or Least Concern which in my view was a mistake in 2020) to Endangered under the criteria C1+2a(ii) as detailed in this document.
My additional preliminary comments are:
A) Under the heading Specific Questions: Do you have any 2026 colony counts or estimates of the 2026 population size?
The Elizabeth Bay colony in southern Namibia (approximately 26.917 S, 15.247 E and adjacent to an extensive coastal diamond mine), which had been surveyed in previous years including in Braby 2011 and in Simmons Braby and Braby 2015*) and noted as declining, was thoroughly re-surveyed on 24 January 2026, and no breeding activity and no bird presence was detected. This leads to the conclusion that this colony is now probably extinct (Dr J Kemper and Dr M Lemerle pers com). This new information confirms the previously assumed declining trend of the population.
It should be noted that due to the difficulty of accessing remote locations in the coastal Namib desert, as well as due to access restrictions due to the Diamond Act regulations for the last century, some potential suitable breeding habitats for Damara terns have been poorly surveyed to date. A few additional breeding localities of this species are suspected to occur within the Tsau//Khaeb National Park in previously unsurveyed areas (so they are not suspected to be recently established, but rather undiscovered to date). Such potential additional breeding localities are unlikely to support large numbers of breeding pairs and are therefore not expected to have consequences for the present assessment, and in particular for the overall declining population trend. However, if new localities are confirmed and assessed by further monitoring efforts, they should be included in future conservation priorities and in threat assessments related to proposed large-scale industrial developments in the region.
*This important reference which gives detailed account and size and trend estimates of all known Damara tern colonies in Namibia at the time has been omitted from the document: Simmons RE, Braby RJ, Braby SJ. 2015. Damara Tern Sternula balaenarum (Sterna balaenarum). Pp 91-95 in: Simmons RE, Brown CJ and Kemper J (Eds). Birds to watch in Namibia: Red, rare and Endemic species. Ministry of Environment and Tourism and Namibia Nature Foundation. Windhoek, Namibia.
B) In Annex 1, under the heading Subpopulation structure: The justification: “This species is migratory and change breeding colony between years, and therefore likely occurs as a single subpopulation” Should be considerably watered down for several reasons:
a. While there are a few examples of marked birds changing breeding colony between years, this was attributed to excessive disturbance on the original colony (RJ Braby pers. com.) and the change of colony was extremely local (< 10 km). At the same time there is ample evidence from many more marked birds that they are in fact very faithful to their breeding sites. So, this argument by itself does not make it likely that the species is a single subpopulation.
b. The recent results from Allport et al 2022 show that the rather outlying south-eastern population (in the Eastern Cape Province) migrates along the East coast of southern Africa (instead of tropical western Africa)… As this breeding population is distant (by more than 500 km) from the West coast birds and migrates through a different pathway to a different wintering destination it is probable that it might constitute a distinct subpopulation from the rest of the species. This considerably weakens the assumption that the species likely occurs as a single subpopulation as stated.
c. Similarly, the small Western Cape Province population being distant by more than 700 km from the rest of the west coast colonies is also likely to be an isolated subpopulation.
d. Further recent evidence from studies being currently conducted in Namibia suggests that the species might actually be fragmented at an even finer scale (including between breeding sites, migrants vs non migrant subpopulations, timing of breeding (including winter breeding) etc…) e.g. Roux et al. 2025.**
** Roux JP, Boorman M, Braby J, Braby RJ. Fijn RC. 2025, A new longevity record for the Damara tern Sternula balaenarum. Namibian Journal of Environment 10, B-12
C) Still in Annex 1, the Extent of Occurrence (EOO) is given as 945 000 Km2. As this criterion is calculated using the minimum convex polygon method and seems to include all subpopulations (including that of the Eastern Cape province) it should be noted that this huge area encompasses a large portion of southern Africa including places up to about 500 km inland and the western edge of the Kalahari Desert. This is therefore very unrealistic for a strictly coastal bird. As this criterion was used in the previous assessment to justify a Least Concern status, this caveat should be noted and emphasized in the text.
Further, the EOO of the Northern Cape Province, Namibian and Angolan part of the population (which constitutes >95% of the species) could reasonably be estimated at about 15 000 Km2 which is only about 1.6% of the present estimate. Again, it should be noted that this criterion, as presently calculated, is giving an extremely misleading and unrealistic result when applied to the Damara Tern.
Dr J-P Roux
jp.roux2023@gmail.com
SEACODE Research Group
I am in full agreement with the proposed status change and with the justification behind it. I also support Dr. Roux’s additional arguments that are provided here as a set of comments. Especially with a surge in planned coastal (terrestrial and marine) developments throughout the Damara Tern’s breeding range, including in protected areas, it is essential that the previously incorrect listing is rectified to ensure appropriate decision-making.
As someone who wrote the PhD thesis “Biology and Conservation of the Damara Tern” (2011), and published multiple papers out of the thesis, and someone who has been part of monitoring Damara Terns, along with my parents (who have monitored since 1980s), since the 1990s, along the entire coastline of Namibia from the Skeleton coast down to the Sperrgebiet, I fully endorse the proposal set forward, as well as those comments made by Dr Roux above. The proposed change to Endangered reflects the reality of the species situation, and will allow conservation efforts to adequately address this.
I strongly agree with the proposal to categorize it as an endangered species. During our IWC, 2026, this species was not sighted, which may indicate a serious decline in its population.
I also fully endorse the proposed change of the status of Damara Tern to Endangered. As Dr Roux points out there are large gaps between breeding populations in Namibia, the very small Western Cape population and that in the Eastern Cape of South Africa.
Based on the reduction in numbers over three generations the regional assessment was close to that of Critically Endangered and the 2015 Regional Assessment was considered to be Critically Endangered (Simmons, R.E. 2015. Damara Tern Sterna balaenarum. In The Eskom Red Data Book of Birds of South Africa, Lesotho and Swaziland. Taylor, M.R., Peacock, F. and Wanless, R.W. (eds). BirdLife South Africa, Johannesburg, South Africa. pp 52-54.
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 22 May 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 22 May 2026, when discussions will re-open.
Preliminary proposal
Many thanks to all contributors above for their comments and support on this proposal. We will ensure that relevant information is captured where appropriate in the final assessment.
We will ensure that the possible extirpation of the Elizabeth Bay colony is captured in the final assessment and will ensure the Simmons et al. 2015 reference is included. We have responded to specific points below:
B) subpopulations:
The information provided is helpful. Please note that the IUCN’s definition of a single subpopulation requires only that “one successful migrant individual per year or less” moves between areas; this definition may differ from other biological or ecological definitions of a subpopulation. Nonetheless, on reflection of the comments, it may be more accurate to suggest a range of 1-3 subpopulations (or more). The information provided in the reference and the comment will be considered and the number of subpopulations will be revised. Please note that the species may no longer qualify as Endangered under Criterion C2a(ii) if it occurs in more than one subpopulation. It will still qualify as Endangered under Criterion C1.
C) EOO:
We recognise that the current EOO includes areas that do not contain suitable habitat for this species. The IUCN Guidelines discourages the use of methods other than a Minimum Convex Polygon when calculating the EOO: “for assessments of criterion B1, exclusion of areas forming discontinuities or disjunctions from estimates of EOO is strongly discouraged.” The purpose of the EOO is to capture the spatial spread of the areas currently occupied by the species and therefore measure the degree to which risks from threatening factors are spread spatially across the species’ distribution, rather than capturing the actual area where the species occurs which is represented by the Area of Occupancy. The Area of Occupancy has not been calculated for this proposal because it is inferred to be larger than 2,000 km2 (the threshold for listing as threatened under Criterion B2), but data on this would be helpful. As such, we will not be revising the EOO to ensure consistency with the IUCN Guidelines and other BirdLife Red List assessments.
Based on available information, our preliminary proposal for the 2026 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 31 May 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 in November 2026, following further checking of information relevant to the assessments by both BirdLife and IUCN.
I appreciate that IUCN’s protocols for calculating and using EOO (by minimum convex polygon) as a measure of spatial spread in species assessments should not be changed. However, it should be explicitly acknowledged in the text as being an unrealistic measure for the assessment of this species – as per Dr. Roux’s original arguments. The reason for this is that the unrealistically inflated EOO was the main argument used in the 2020 revision leading to the erroneous “Least Concern” classification.
With regard to subpopulations, I think at least two should be considered. The birds breeding in South Africa’s Eastern Cape are now spending the non-breeding period in Mozambique. This has been confirmed from sightings of leg-flagged birds from the Eastern Cape (see Allport et al. 2022, Martin et al. in press). About 100 birds have been recorded in Mozambique in the Austral winter so the bulk of the population that breeds in Namibia presumably still migrates to the Gulf of Guinea, West Africa.
Martin, A.P, Whittington, P.A., Dyer, B.M., Crawford, R.J.M.C. & Makhado, A.B. In press. Numbers, trends, status, movement and conservation of Damara Terns (Sternula balaenarum) 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.
I fully endorse the proposed change in status and support comments and arguments made by Dr. Jessica Kemper and Dr. Jean-Paul Roux. The sooner the classification is changed from the erroneous “Least Concern” to “Endangered” the better for the improved long-term conservation of the species.
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 8 June 2026.