To suggest a reassessment of a species that is currently not under active discussion on the Forums, please use the Comment box below.
To suggest a reassessment of a species that is currently not under active discussion on the Forums, please use the Comment box below.
Last year, SEO/BirdLife was commisioned by the Spanish Government to update the conservation status and trends for Spanish populations of breeding birds. I participated in the research team, and after reviewing the most recent data, consulting to national experts and following IUCN standards, we proposed updates on the Spanish Red List Book (published on 2021). These proposals are relevant to global assessments concerning endemics from the Canary Islands. Our proposals were to uplist Columba bolli (LC to NT), Columba junoniae (NT to VU) and Saxicola dacotiae (NT to EN). This last case is quite clear, because recent (2024) comprehensive census have shown a demographic colapse, in relation to previous census from 2005-2006: EN [A2bc, B1b (i, ii, iv, v) c (i, ii, iii, iv)]. More information on this Spanish assessment can be obtained from SEO/BirdLife (Juan Carlos del Moral and Jorge Orueta).
The White-throated Hawk (Buteo albigula) was last assessed in 2018, and is currently considered as a species of Least Concern, with a global population estimated in 600-6,700 mature individuals, and an unknown population trend (Birdlife International 2018). However, this assessment lacks of rigor, since considers the species as “Not a migrant”, with a very large range (EOO of 4,500,000 km²), including mountain forests of Chile, Argentina, Bolivia, Peru, Ecuador, Colombia, and Venezuela (BirdLife International 2018). The White-throated Hawk has been known as a migratory species since the 2,000s (Pavez 2000, 2007, Trejo et al. 2007), and several studies have shown that the only breeding grounds are in central and southern Chile (Pavez et al. 2004, Silva et al. 2008, Rivas-Fuenzalida et al. 2013, 2015, 2019, 2026), and in the western Argentine Patagonia (Casas and Gelain 1995, Gelain et al. 2001, Trejo et al. 2004, 2007, Rivas-Fuenzalida et al. 2016, 2026). This species is a full migrant (i.e.: >95% of its global population is migratory, with few individuals remaining in breeding or wintering grounds) (Bechard et al. 2010, Medel et al. 2018, Rivas-Fuenzalida and Quispe-Flores 2021, Rivas-Fuenzalida et al. 2023, 2026). This implies that is a single population that breeds in southern South America and migrates towards the tropical Andes (Rivas-Fuenzalida et al. 2026), with an Area of Occupancy (AOO) in the breeding grounds that covers approximately 165,000 km2 (Rivas-Fuenzalida et al. 2026). In 2022, we identified the main migratory bottleneck for the species in central Chile, where is estimated that at least 84% of the global breeding population passes through (Rivas-Fuenzalida et al. 2023), including the Argentinian population which follows the corridor along the western slopes of the Andes Mountain Range (Bechard et al. 2010, Juhant and Seipke 2010). After three years of counting at this site, and extrapolating presence and abundance data from the Andean Forest (Chile and Argentina) and Chilean Coastal Forests, supported by distribution models by eBird Status and Trends (Fink et al. 2023), records from eBird and our own data on pair densities (Rivas-Fuenzalida et al. 2026), we confirmed that a proportion ≥84% of the global breeding population is in the Andean forests and uses the bottleneck. Considering that at least 2/3 of the observed passage correspond to mature birds, we estimate the global population to be 5,400 to 6,400 mature individuals (Rivas-Fuenzalida et al. 2026), close the previous IUCN maximum estimate of 6,700 mature individuals (Birdlife International 2018). As population trends have not been assessed, the breeding habitat loss can be used as a proxy for population decline. Using data from Global Forest Watch 2025 (based on data from Hansen et al 2013), we determined that the tree cover in the species’ complete mapped breeding range (including Chile and Argentina) has decreased by c. 15% between 2001 and 2024 (Rivas-Fuenzalida et al. 2026). Habitat loss is a continuous and growing threat for the species. Global climate change is linked with recent warming and drying of the Patagonian forests, which, combined with direct human impacts such as the expansion of highly flammable exotic conifer plantations, and other direct actions, are favoring the occurrence of increasingly large and severe fires in the Patagonian forests of Chile and Argentina (Veblen et al. 2011, Iglesias and Whitlock 2014). Furthermore, the species is among the most affected raptors by human persecution related to poultry predation in the Neotropics, being recognized as a priority species for conservation measures to reduce this threat (Rivas-Fuenzalida et al. 2025). Thus, human persecution can increase the population decline over the percent of habitat loss. A new threat for the species is the proliferation of wind farms in both, breeding areas and more importantly, along its migratory routes, which can potentially increase adult and juvenile mortality. These results suggest that populations of this species may be experiencing a continuous population decline, estimated in over 15% in the last 20 years (less than 3 generations or 29.1 years according to Birdlife International 2018).
With a global population of less than 10,000 mature individuals, and a continuous decline of more than 10% in three generations, the species meets the C(1) criteria for Vulnerable status (Rivas-Fuenzalida et al. 2026).
References
Bechard, M. J., L. Sympson, K. L. Bildstein, and D. R. Barber (2010). White-throated Hawk (Buteo albigula): the first transequatorial raptor migrant from South America. Second Conference Bird Migration and Global Change: Movement Ecology and Conservation Strategies: 17.
BirdLife International (2018). Species factsheet: White-throated Hawk Buteo albigula. Downloaded from https://datazone.birdlife.org/species/factsheet/white-throated-hawk-buteo-albigula 27/01/2026
Casas, A. E., and M. Gelain (1995). Nuevos datos acerca del estatus del aguilucho andino Buteo albigula en la Patagonia argentina. Hornero 14:40-42.
Gelain, M., V. Ojeda, A. Trejo, L. Sympson, G. Amico, and R. Vidal (2001). Nuevos registros de distribución y nidificación del aguilucho andino (Buteo albigula) en la Patagonia argentina. Hornero 16:85-88.
Fink, D., T. Auer, A. Johnston, M. Strimas-Mackey, S. Ligocki, O. Robinson, W. Hochachka, L. Jaromczyk, C. Crowley, K. Dunham, A. Stillman, I. Davies, A. Rodewald, V. Ruiz-Gutierrez, C. Wood (2023) eBird Status and Trends, Data Version: 2022; Released: 2023. Cornell Lab of Ornithology, Ithaca, New York. https://doi.org/10.2173/ebirdst.2022
Hansen, M. C., P. V. Potapov, R. Moore, M. Hancher, S. A. Turubanova, A. Tyukavina, D. Thau, S. V. Stehman, S. J. Goetz, T. R. Loveland, A. Kommareddy, A. Egorov, L. Chini, C. O. Justice, and J. R. G. Townshend (2013). High-resolution global maps of 21st-century forest cover change. Science 342:850–853.
Iglesias, V., and C. Whitlock (2014). Fire responses to postglacial climate change and human impact in northern Patagonia (41-43°S). Sustainability Science 111: E5545-E5554.
Juhant, M. A., and S. H. Seipke (2010) Austral autumn migration counts of raptors in Argentinean Patagonia. Hawk Migration Studies 35:7–10.
Medel, J., K. L. Bildstein, R. P. Schlatter, and J. G. Navedo (2018). Discovery of an austral migratory corridor for raptors in South America. Journal of Raptor Research 52(1):89-93.
Pavez, E. F. (2000). Migratory movements of the White-throated Hawk (Buteo albigula) in Chile. Journal of Raptor Research 34:143-147.
Pavez, E. F. (2007). Buteo albigula en vuelo migratorio en Chile central. Boletín Chileno de Ornitología 13:64.
Pavez, E. F., C. González, B. A. González, C. Saucedo, S. A. Alvarado, J. P. Gabella, and A. Arnello (2004). Nesting of the white-throated hawk (Buteo albigula) in deciduous forests of central Chile. Journal of Raptor Research 38:186-189.
Rivas-Fuenzalida T., J. Medel, and R. A. Figueroa (2013). Nesting territory characteristics of a migratory South American forest hawk, the White-throated Hawk (Buteo albigula) (Aves : Accipitridae), in temperate rainforest remnants of Araucanía, southern Chile. Journal of Natural History 47:1129-1142.
Rivas-Fuenzalida, T., N. Asciones-Contreras, A. Maureira, M. Almonacid, E. Cifuentes, and K. Roa (2015). Nidificación del aguilucho chico (Buteo albigula) en un hábitat exótico dentro de un área urbana del sur de Chile. Boletín Chileno de Ornitología 21(1-2):134–139. http://aveschile.cl/web/wp-content/uploads/2016/03/CB05-Rivas-F-et-al.pdf
Rivas-Fuenzalida, T., M. Costa, and N. Asciones-Contreras (2016). Primer registro de nidificación y nuevos datos de presencia del Aguilucho de cola rojiza (Buteo ventralis) en la Patagonia Argentina. Nótulas Faunísticas Segunda Serie 199:1-16.
Rivas-Fuenzalida, T., E. Borquez, D. Romo-Cancino, E. Ziehlmann, M. Otarola, J. Díaz-Tavie, S. Torres, and V. Raimilla (2019). Extensión del límite de distribución austral del Aguilucho chico (Buteo albigula) en Chile. Revista Chilena de Ornitología 25:86-91.
Rivas-Fuenzalida, T., and Y. Quispe-Flores (2021). Áreas de escala migratoria y dormidero comunitario del Aguilucho chico (Buteo albigula) durante su migración hacia el norte en los Andes. Ornitología Neotropical 32:170-174.
Rivas-Fuenzalida, T., J. Gallardo, S. Castrilli, K. Burgos-Andrade, A. M. Morales, J. Miranda, S. Kohn, P. Camacho, Á. García, V. Rosales, E. C. Gaitán López, A. Monroy-Ojeda, A. Aguilera, F. Angulo, D. Orizano, F. Andrade, F. Alí, L. Saavedra, R. Figueroa, F. H. Vargas, J. S. Restrepo-Cardona, and J. M. Grande (2025). Human-wildlife conflict related to poultry predation as threat for diurnal raptors in the Neotropics: a call to action. Raptor Research Foundation 2025 Conference, 14-18 October 2025, San José, Costa Rica.
Rivas-Fuenzalida, T., S. Castrilli, E. Ziehlmann, K. Burgos-Andrade (2023). A migratory bottleneck for the White-throated Hawk (Buteo albigula) in the Andean foothills of central Chile. Ornitología Neotropical. 34:167–173.
Rivas-Fuenzalida, T., S. Castrilli, J. Toledo, R. Figueroa, and P. Pyle (2026). White-throated Hawk (Buteo albigula), version 4.0. In Birds of the World (S. M. Billerman and F. Medrano, Editors). Cornell Lab of Ornithology, Ithaca, NY, USA. Retrieved from Birds of the World: https://birdsoftheworld.org/bow/species/whthaw1/4.0
Silva-Rodríguez, E. A., J. E. Jiménez, M. A. Sepúlveda-Fuentes, M. A. Sepúlveda, I. Rodríguez-Jorquera, T. Rivas-Fuenzalida, S. A. Alvarado, and R. A. Figueroa R. (2008). Records of the White-throated Hawk (Buteo albigula) along the Chilean coastal forests. Ornitología Neotropical 19(1):129-135.
Trejo, A., P. Capllonch, and L. Sympson (2007). Migratory status of the White-throated Hawk (Buteo albigula): what do we know up to now? Ornitología Neotropical 18(1):11-19.
Trejo, A., V. Ojeda, L. Sympson, and M. Gelain (2004). Breeding biology and nest characteristics of the White-throated Hawk (Buteo albigula) in northwestern Argentine Patagonia. Journal of Raptor Research 38(1):1-8.
Vásquez, A., and P. Allasi (2017). Registros documentados del Aguilucho de garganta blanca (Buteo albigula) al oeste de la cordillera de los Andes en Arequipa y Lambayeque. Boletín de la Unión de Ornitólogos de Perú 12:24-26.
Veblen, T. T., A. Holz, J. Paritsis, E. Raffaele, T. Kitzberger, and M. Blackhall (2011). Adapting to global environmental change in Patagonia: What role for disturbance ecology? Austral Ecology 36:891—903.
We call for:
(a) recognition of Mauritanian Spoonbills, i.e. the subspecies Platalea leucorodia balsaci, in the IUCN Red List, and
(b) the assignment ‘Vulnerable’ by the IUCN SSG, based on the following arguments published in 2025 by Piersma et al. in ORYX:
According to the IUCN Red List of Threatened Species (BirdLife International, 2019), Eurasian Spoonbills Platalea leucorodia have “an extremely large range”, with a population size that “is very large”, “and hence … the species is evaluated as Least Concern”.
This foregoes the knowledge that there is at least one small, and peculiarly resident, population confined to within the Parc National du Banc d’Arguin in Mauritania, spoonbills that in 1974 were recognized as a separate subspecies (de Naurois & Roux, 1974; Triplet et al., 2008). It was named balsaci, to distinguish them from the nominate migratory subspecies leucorodia also occurring in the area during the non-breeding season. With the type specimen collected on the islet of Zira on 8 June 1972, balsaci spoonbills (now called Mauritanian Spoonbills) were described as being of smaller body size than leucorodia with the yellowish markings on the spatulate end of the beak being absent or vestigial and the ochre band at the base of the neck absent or vestigial too. Of the 17 breeding specimens collected at Banc d’Arguin from 1960-1972 (stored and curated at MNHN, Paris), nine had completely black bill tips and eight had barely visible yellow marks. The proposed balsaci spoonbills were considered to be fully resident (de Naurois & Roux, 1974), but joined during the nonbreeding part of the year, and sometimes even within the Banc d’Arguin breeding season, by leucorodia migrants from breeding colonies in Europe (identifiable on the basis of colour rings). Piersma et al. (2012) confirmed leucorodia and balsaci to be genetically distinct at the expected subspecies level, but with evidence of gene flow from birds breeding in Europe to those breeding at Banc d’Arguin.
Mauritanian Spoonbills P. l. balsaci are not listed as a taxon of distinction and concern in the IUCN Red List of Threatened Species (Birdlife International, 2019). In addition to the threats listed by Triplet et al. (2008), introgression is now a concern.
We propose that the balsaci subspecies should be Red Listed as ‘Vulnerable’ based on criteria B1 and C1 (https://www.iucnredlist.org/resources/summary-sheet).
B1: occurring over, at most, 10% of the upper boundary of 20,000 km², and (B1a) limited to a single location, the Parc National du Banc d’Arguin; C1: a population size of ˂10,000 individuals, with the likelihood of at least a 10% reduction in three generations because of their reliance on low-lying breeding islets threatened by sea level rise.
We hope you can take this suggestion into consideration.
Best wishes, also in name of the scientific team Theunis Piersma and Hacen el-Hacen,
Janske van de Crommenacker
Birdlife Netherlands
References:
BirdLife International (2019) Platalea leucorodia (amended version of 2016 assessment). The IUCN Red List of Threatened Species 2019.
https://dx.doi.org/10.2305/IUCN.UK.2019-3.RLTS.T22697555A155460986.en. Accessed on 20 April 2025.
de Naurois, R. & Roux, F. (1974) Précisions concernant la morphologie, les affinités et la position systematique de quelques oiseaux du Banc d’Arguin (Mauritanie). L’Oiseau et la R.F.O., 44, 72–84.
Piersma, T., van der Velde, M., El-Hacen, E.-H.M., Lok, T. & Overdijk, O. (2012) Molecular verification of the subspecies status of the Mauritanian Spoonbill Platalea leucorodia balsaci. Ardea, 100,131–136.
Piersma, T., Camara, M., de Goeij, P., Loos, B., Oortwijn, T. & El-Hacen, M. E.-H. (2025). Is the resident subspecies of the Eurasian spoonbill in Mauritania, Platalea leucorodia balsaci, threatened by introgression of genes from the migratory nominate subspecies leucorodia? Oryx, 59, 579–583. doi:10.1017/S0030605325101737
Triplet, P., Overdijk, O., Smart, M., Nagy, S., Schneider-Jacoby, M., Karauz, E.S., Pigniczki, C., Baha El Din, S., Kralj, J., Sandor, A. & Navedo, J.G. (2008) International Single Species Action Plan for the Conservation of the Eurasian Spoonbill Platalea leucorodia. AEWA Technical Series No. 35. Bonn, Germany.
I would like to propose White-cheeked Tern Sterna repressa for reassessment, or at least for a focused review of breeding-site vulnerability.
Although the species is currently assessed as Least Concern, the current assessment may underestimate the loss, degradation, and reduced security of functional breeding islands, especially in the Persian Gulf and adjacent parts of the Arabian Sea and Red Sea region. BirdLife DataZone already indicates continuing decline in mature individuals, extreme fluctuations in mature individuals and subpopulations, and continuing decline in the number of subpopulations. My concern is that these patterns may be linked not only to population fluctuation, but also to the progressive loss or degradation of safe breeding islands.
White-cheeked Tern is a colonial ground-nesting seabird that depends on small offshore islands, open sandy or rocky coastal ground, sparsely vegetated areas, and low-disturbance breeding conditions. In our annual surveys of breeding seabirds on Iranian Persian Gulf islands, we have repeatedly observed that White-cheeked Terns often breed on beaches, sandy margins, rocky coastal areas, and open ground before dense vegetation begins. This makes their nests especially exposed to the first areas reached by people landing on islands, whether tourists, fishermen, unauthorized visitors, or personnel associated with permanent infrastructure.
Published evidence from the northern Persian Gulf suggests a severe historical decline. Tayefeh et al. (2011) reported that the breeding population of White-cheeked Tern on northern Persian Gulf islands had declined by about 98% since the 1970s, from an estimated 100,000 to 300,000 pairs in the 1970s to 2,197 pairs in 2010. The same study noted that, unlike other breeding waterbirds in the region, White-cheeked Tern had noticeably decreased. Behrouzi-Rad (2013) also reported a decline in recorded breeding pairs across surveyed Persian Gulf islands from 3,589 pairs in 2004 to 968 pairs in 2009, and reported no breeding on Kharku during 2003 to 2009.
A key concern is that this decline may reflect the functional loss of breeding islands. Several islands that were formerly remote, uninhabited, or suitable for breeding seabirds are no longer effectively available as low-disturbance breeding sites. Tayefeh et al. (2011) noted that islands such as Larak, Farour, Greater Tunb, Lesser Tunb, and Kharku had become inhabited or supported military bases, oil and gas installations, and transportation infrastructure, making them unsuitable for breeding colonies of ground-nesting waterbirds. Based on current regional knowledge from Iran, similar concerns apply to formerly important or potentially suitable breeding islands such as Lesser Farour, Siri, Farsi, and Kharku, which are no longer functionally uninhabited islands and now contain permanent military, restricted-use, or other human infrastructure.
This matters because the species does not only require “islands” in a geographic sense. It requires functional breeding islands: open, low-disturbance, predator-free or low-predator sites where ground nests can persist through incubation and chick-rearing. When a former breeding island becomes permanently occupied, militarized, developed for oil and gas, or frequently visited, it may remain an island on the map but cease to function as breeding habitat.
Recent annual surveys by the Hormozgan Department of Environment and AvayeBoom Bird Conservation Society also support this concern at the site level. On Sheedvar/Shidvar Island, surveys in 2021 and 2022 documented continued breeding by White-cheeked Tern, but also recorded important threats including unauthorized tourist access, signs of domestic cat presence in 2021, illegal egg collection, and repeated human disturbance during the breeding season. The 2021 survey noted that White-cheeked Terns and other exposed-nesting terns breed on sandy coastal areas that are accessible to humans and domestic cats, unlike Bridled Terns that nest more in dense vegetation. The same report suggested that human presence and domestic cats may have contributed to declines in several breeding tern species on the island.
I therefore suggest that White-cheeked Tern should be reassessed, with particular attention to whether continuing decline in the area, quality, and security of breeding habitat is being sufficiently captured. The reassessment should examine:
updated breeding counts from the Persian Gulf, Arabian Sea, Gulf of Oman, and Red Sea;
the number of active, former, and functionally lost breeding islands;
evidence of colony abandonment, decline, or breeding-site shifts linked to human disturbance, tourism, fishing access, egg collection, military or restricted-use infrastructure, oil and gas infrastructure, introduced predators, and vegetation change;
whether some islands currently mapped or historically listed as breeding sites are still functionally suitable for ground-nesting seabirds;
whether monitoring gaps on restricted, military, or inaccessible islands may be masking local declines; and
whether the current Least Concern category adequately reflects continuing decline in the quality and availability of safe breeding habitat.
I am not suggesting that a category change can be concluded without a full range-wide review. However, the available evidence from the Persian Gulf suggests that the species should at least be brought back onto the reassessment agenda. Even if the species remains relatively widespread, the loss of safe breeding islands may cause local colony abandonment and reduced breeding output before range-wide population decline is adequately detected.
I would be happy to help compile evidence from Iran, including published sources and unpublished annual survey data from Sheedvar/Shidvar, Bani Farour/Lesser Farour, Kharku, Siri, Farsi, Nakhilu, Omol-Karam, Khan/Morghu, and other relevant Persian Gulf islands.
References
Behrouzi-Rad, B. (2013). Breeding species of waterbirds on 10 islands of Persian Gulf in 2009. Octa Journal of Environmental Research, 1(1), 52-64.
Hormozgan Department of Environment & AvayeBoom Bird Conservation Society. (2021). Report on the census and population estimate of breeding bird species on Sheedvar Island in 2021. Unpublished report.
Hormozgan Department of Environment & AvayeBoom Bird Conservation Society. (2022). Report on the census and population estimate of breeding bird species on Sheedvar Island in 2022. Unpublished report.
Scott, D. A. (2007). A review of the status of the breeding waterbirds in Iran in the 1970s. Podoces, 2(1), 1-21.
Tayefeh, F. H., Zakaria, M., Amini, H., Ghasemi, S., & Ghasemi, M. (2011). Breeding waterbird populations of the islands of the northern Persian Gulf, Iran. Podoces, 6(1), 49-58.
Tohidifar, M. (2014/2015). Report on population estimates and ringing of terns on Sheedvar and Bani Farour Islands. Hormozgan Department of Environment. Unpublished report.