Archived 2018 topic: Moustached Warbler (Acrocephalus melanopogon): request for information.

BirdLife species factsheet for Moustached Warbler

Moustached Warbler (Acrocephalus melanopogon) has a large range, breeding across southern Europe, the Middle East and Central Asia, from Spain east to Kazakhstan. Some populations are migratory, wintering in North Africa, the Mediterranean, the Middle East, Central Asia and NW Indian Subcontinent. The population size has been roughly estimated at 434,000-712,000 mature individuals, based on an estimate of 76,100-124,000 pairs in Europe (BirdLife International 2015) and the fact that Europe is estimated to form c.35% of the global range. The population has been suspected to be stable in the absence of evidence for any declines or substantial threats (del Hoyo et al. 2006). Given the species extremely large range, stable trend and extremely large population, the species has not been considered to approach the thresholds for listing as Vulnerable against any criterion, and is consequently currently listed as Least Concern (IUCN 2017).

We have recently received information that a research project focussing on the species in five countries since 2002 has indicated that the population is declining (P. Villányi in litt. 2018). We are therefore requesting further information in order to reassess the species’s Red List status.

Our current information on the species’s conservation status will now be compared to all Red List Criteria.

Criterion A – The species’s conservation status in Europe was recently assessed for the European Red List of Birds (BirdLife International 2015). The European trend was not known, but it was believed that the species was not decreasing sufficiently rapidly to approach the thresholds under Criterion A (30% decline over ten years or three generations). The species’s global trend has previously been assumed to be stable in the absence of evidence to the contrary (del Hoyo et al. 2006). Research in five countries from 2002 has suggested a population decline (P. Villányi in litt. 2018), however we do not currently have information on the magnitude of this decline, or the proportion of the population that is experiencing this decline. Should information be available to indicate that the population is declining at a rate that would equate to a 30% or more reduction in the species’s global population across the last 13 years (three generation lengths); or in the next 13 years; or across 13 years that include both the past and the future; then the species may qualify for listing as threatened under Criterion A. If information suggests that the rate of reduction approached 30% across three generation lengths, then the species may qualify for listing as Near Threatened under Criterion A.

Criterion B – The species’s extent of occurrence (EOO) has been estimated as 11,700,000km2. The area of occupancy (AOO) has not been estimated, but is extremely unlikely to approach the threshold for Vulnerable of 2,000km2. The species therefore qualifies for listing as Least Concern under Criterion B.

Criteria C and D – The species’s population size was estimated as 434,000-712,000 mature individuals, based on an estimate of 76,100-124,000 pairs in Europe (BirdLife International 2015) and the fact that Europe is estimated to form c.35% of the global range. Although this estimate has a high level of uncertainty, even if the population is declining, the total number of mature individuals is very unlikely to approach the population thresholds for these Criteria (10,000 and 1,000 mature individuals). The species does not have a restricted AOO or number of locations such that a plausible future threat could drive the species to Critically Endangered or Extinct within a very short time. The species therefore qualifies for listing as Least Concern under Criteria C and D.

Criterion E – To the best of our knowledge no quantitative assessment of the probability of extinction has been conducted for Moustached Warbler, and so it cannot be assessed against this criterion.

To get a clearer assessment of the species’s status, information is requested on the population size, trends and threats of the Moustached Warbler since the mid-2000s, especially from outside of its European range.

In particular, to enable us to assess the magnitude of any population reduction and thus assess the species’s status under Criterion A, it will be important for us to know the rate of any detected population decline, and the locations where the decline has been estimated.

Please note that this topic is not designed to be a general discussion about the ecology of the species, rather a discussion of the species’s Red List status. Therefore, please make sure your comments are about the proposed listing.

An information booklet on the Red List Categories and Criteria can be downloaded here and the Red List Criteria Summary Sheet can be downloaded here. Detailed guidance on IUCN Red List terms and definitions and the application of the Red List Categories and Criteria can be downloaded here.



BirdLife International. 2015. European Red List of Birds. Office for Official Publications of the European Communities, Luxembourg.

del Hoyo, J.; Elliott, A.; Christie, D. 2006. Handbook of the Birds of the World, vol. 11: Old World Flycatchers to Old World Warblers. Lynx Edicions, Barcelona, Spain.

IUCN. 2017. The IUCN Red List of Threatened Species. Version 2017-3. Available at:  (Accessed: 19 February 2018).

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5 Responses to Archived 2018 topic: Moustached Warbler (Acrocephalus melanopogon): request for information.

  1. In Turkey, we may have some data on the distribution of the species but no data on the population sizes at specific sites. It is a common and widespread species especially in central or more continental parts of the central Turkey and also at the wetlands in the Mediterranean region. I would not argue against a decision to increase the threat status of the species, in contrary I would welcome it and see it as an opportunity to think about the real status of the species in Turkey and the bordering countries.

  2. James Westrip (BirdLife) says:

    Preliminary proposals

    Based on available information, our preliminary proposal for the 2018 Red List would be to retain the species as Least Concern. New information regarding the species status should be forthcoming from across the species’s European range, as part of regional assessments, which will allow for a clearer assessment of the species’s status.

    There is now a period for further comments until the final deadline in mid-July, after which the recommended categorisations will be put forward to IUCN.

    Please note that we will then only post final recommended categorisations on forum discussions where these differ from those in the initial proposal.
    The final 2018 Red List categories will be published on the BirdLife and IUCN websites in November, following further checking of information relevant to the assessments by both BirdLife and IUCN.

  3. Dear Commitee Members,

    I strongly welcome the proposal to list the Moustached Warbler (Acrocephalus melanopogon) as a Vulnerable species, despite the fact of apparently not crossing the threshold for listing it as such against any criterion.

    Although the extremely large, the distribution of the species is very fragmented, and we have no information of the viability of several patches noted on the distribution map. In Romania, no there was no targeted survey whatsoever to assess the national breeding population size and it’s trends, and I consider all prior expert opinions highly erroneous.

    As described in Chișamera et al. (2010) the presumed breeding population estimates are smaller and smaller at every reporting, while they conclude that the species is än occasional or accidental breeding species” while they do not exclude the existence of a small breeding population in the Danube-Delta:

    Weber et al. (1994): 10000-20000 breeding pairs
    Dvorak (1997): 10000-30000 breeding pairs
    Munteanu et al. (2002): 8000-10000 breeding pairs
    EC reporting under Art. 12 (2008-2012): 100-1000 breeding pairs

    Chișamera et al. (2010) underlines the fact that despite of extended ringing campaign between 2004 and 2010 in the Danube Delta, out of the 22500 ringed passerines only 110 individuals were Moustached Warblers, and the large population on the distribution maps in Western Romania are virtually non-existent and are based on old data by Linția (1944. 1946) and on several misidentified individuals.

    Acording to, the database of the Romanian Rarities Committee, there is only one observation from 2017 outside the Danube Delta in the core breeding season (1st of May – 1st of July), with several observations in the spring an autumn migration period (for further information visit

    Also, while Chituc spit is considered one of the best places to study passerine migration in Romania, beeing South of the Danube Delta and acting as a funnel for passerines (Marton, 2017), from 48000 birds ringed in the autumn migration between 2014 and 2017, only 30 individuals of Moustached Warblers were caught, which would suggest only a small breeding population in the Danube Delta (if we assume that the population from the Danube Delta migrates at all).

    To conclude, while we have a huge gap in our knowledge regarding the Romanian breeding population, I am highly confident that any breeding attempts outside the Danube Delta are only accidental and the reported population size under Article 12 is as close as we can guess to the real national population size, and this might be a recurring problem in the case of all Balkan, East European and Asian populations, in which case the listing of Moustached Warbler as Vulnerable would be recommended.

    Best regards,
    Attila Marton

    Chișamera G, Pocora V, Gogu MB, Adam C (2010) Phenology and biometrics of Moustached Warbler Acrocephalus melanopogon (Passeriformes: Sylvidae) in Romania. Travaux du Muséum National d’Histoire Naturelle “Grigore Antipa” vol LIII, pp. 319-328, DOI: 10.2478/v10191-010-0022-7

    Dvorak M (1997) Acrocephalus melanopogon in Hagemeijer W, Blair M (eds.) The EBCC Atlas of European Breeding Birds: Their Distribution and Abundance, T & AD Poyser, London, p. 903

    European Commission Reporting tool under Article 12 (2008-2012)

    Linția D (1944) Catalogul sistematic al Faunei Ornitologice Române, cu deosebită considerație la materialul indigen din Muzeul Banatului “Secția ornitologicã Prof. D. Linția” a Municipiului Timișoara. Institutul de Arte Grafice “Ardealul”, pp. 166

    Linția D (1946) Păsările României Tom. 1. Fundația Pentru Literatură și Artă, pp. 435

    Marton A (2018) Raportul taberei de inelare de pe Grindul Chituc din perioada 2014-2017. Asociația „Grupul Milvus”, pp. 93

    Munteanu D, Papadopol A, Weber P (2002) Atlasul păsărilor clocitoare din România, 2nd edition, Publicațiile Societății Ornitologice Române, vol. 16, pp. 152

    Weber P, Munteanu D, Papadopol A (1994) Atlasul provizoriu al păsărilor clocitoare din România. Publicațiile Societății Ornitologice Române, vol 2, p. 148

  4. Luca Puglisi says:

    The breeding distribution of the moustached warbler in Italy is scattered in the central regions and to some extent also on the Adriatic coast. In the late ‘90s, its population numbered 800-1000 bp, mainly concentrated at three Tuscan sites accounting for more than 90% of the national population: 500-580 bp were estimated at Massaciuccoli and 160-220 at Fucecchio and 40-65 at Porta (Quaglierini 2002). This figure already accounted for the disappearance of the second largest Italian population, due to local habitat changes at the Diaccia Botrona marsh in the late ‘80s.
    The species was listed as Vulnerable in the Italian Red List, its population having lost 17% in ten years (Peronace et al. 2012). Since then, it disappeared from several sites while the three main population units clearly diminished; in recent years 200-450 bp were estimated at Massaciuccoli, less than 20 at Fucecchio and 10-20 at Porta (Centro Ornitologico Toscano, unpubl. data). On the whole, the Italian national population of Moustached warbler could currently not exceed 500 bp.

    PERONACE, V., J. CECERE, M. GUSTIN and C. RONDININI. 2012. Lista Rossa 2011 degli Uccelli Nidificanti in Italia. Avocetta 36: 11–58.
    QUAGLIERINI, A. 2002. Distribuzione e status del Forapaglie castagnolo Acrocephalus melanopogon, nidificante in Italia: risultati preliminari. Rivista Italiana di Ornitologia 71: 187–197.

  5. James Westrip (BirdLife) says:

    As the original discussion topic above made clear, the only Red List criterion potentially relevant to the global status of this relatively common and widespread species is Criterion A, i.e. population reduction.

    The global status of this species was last reviewed in 2016, using the newly collated information published in the European Red List of Birds (ERLoB) in 2015. Although the national trend of this species was reported as unknown in some European countries and declining in a few, it was also reported as stable in others, and even as increasing (by between 5% and 30% between 1980 and 2012) in Russia, which is thought to hold around 60% of the entire European breeding population (

    In the absence of any evidence for an overall decline approaching (for NT) or exceeding (for VU) 30% over three generations (c. 13 years) in Europe, the species was listed as Least Concern in ERLoB 2015. Similarly, in the absence of any evidence for such declines in the rest of its global range in Central Asia, the Middle East and North Africa, the species was retained as Least Concern on the global Red List.

    The current (2018) discussion was prompted by a suggestion that the species was declining in various European countries, without specifying the magnitude or geographical extent of that decline. Efforts to acquire more quantitative information about that putative decline, and to solicit recent trend information from outside Europe, have not yielded any responses that allow any conclusion other than Least Concern to be reached. Therefore, as explained in the provisional decision above, this topic will now be closed, and the global status of this species will be retained as Least Concern on the 2018 Red List.

    In 2019, EU Member States will again report to the European Commission on the national population size and trend of this and all other regularly occurring bird species in their countries, under Article 12 of the EU Birds Directive. Should those new data suggest that the species is now declining overall at rate approaching or exceeding 30% in 13 years, especially when combined with any new data from the rest of Europe, then a new discussion of its global status could be considered in 2020. The same applies to any other European species for whom the 2019 data suggest a review may be warranted. But once again, the outcome will also depend partly on the availability of information from outside Europe, especially for species such as this, where a significant proportion of the global range falls outside Europe.

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