Archived 2020 topic: Yelkouan Shearwater (Puffinus yelkouan) – request for information on population trends

Please note: This discussion topic is one of a set about species that are endemic or nearly endemic to the European Union (EU), and whose status in the EU therefore effectively determines their global status. To ensure consistency between the 2020 global and EU Red List assessments of these species, this set of topics is being fast-tracked through BirdLife’s Globally Threatened Bird Forums to inform decisions on the EU (and global) status of relevant species, which must be finalised and communicated to the European Commission by mid-April 2020. Topics on other species will be posted on the Forums shortly, for discussion later in the spring, as per usual. The results of the 2020 global Red List update for birds will be published by IUCN and BirdLife in early December.

Yelkouan Shearwater Puffinus yelkouan is endemic to the Mediterranean and Black Seas, breeding from S France and E Algeria east to Greece and Bulgaria; breeding is also suspected in Turkey, but still not proven (Carboneras et al. 2020). It is currently precautionarily listed as Vulnerable, because when last assessed it was considered plausible that its population might be declining overall at a rate of >30% over three generations.

Globally, it has an extremely large extent of occurrence (>5 million km2), and hence does not approach the thresholds for Vulnerable under the range size criteria (B and D2). Its population size is also moderately large (with an estimated 39,000–62,000 mature individuals in Europe alone; BirdLife International 2015), and hence does not approach the thresholds for Vulnerable under the population size criteria (C and D1). Therefore, the only potentially relevant criterion is A, which relates to reductions in population size. When last assessed, the population was thought likely to be declining overall at a rate which, if continued over three generations (54 years, based on a generation length estimated by BirdLife at that time to be 18 years), may have resulted in an overall population decline of >30% (the threshold for listing as Vulnerable under Criterion A).

That assessment was informed by a discussion on this Forum in 2015. It highlighted some previous studies in France and Malta indicating a population decline, caused by low breeding success due to predation by introduced mammals and low adult survival owing to fisheries bycatch and predation. However, some other studies showed population increases, and high counts (up to 90,000 birds) in the Bosphorus indicated potentially large but as yet undiscovered colonies in the E Mediterranean or Black Sea. The conclusion was to precautionarily retain the species’s previous listing as Vulnerable, while noting that if further study and monitoring provided evidence of large stable or increasing populations, the species’s status would be reviewed and may warrant reclassifying in the future. Since then, a number of significant developments have occurred, necessitating a status review.

First, during 2016-2017, a Species Action Plan (SAP) for the conservation of Yelkouan Shearwater was developed, through a working group involving experts and stakeholders from across its global range (Gaudard 2018). The SAP included an updated global breeding population estimate of c. 21,000–36,000 pairs (i.e. 42,000–72,000 mature individuals), with declines reported from a few countries (mainly based on poor quality data), but trends generally still reported as unknown. It highlighted the most critical threat affecting the species as bycatch, with decreasing fish stocks, chronic pollution and predation by alien species also identified as high threats.

Second, in autumn 2017, a range of actors joined forces to eradicate invasive rats from the island of Tavolara (a limestone massif off the NE coast of Sardinia, Italy), which hosts the world’s largest known breeding colony of Yelkouan Shearwaters, estimated at 9,600-13,000 pairs, or c. 36–46% of the global population (LIFE Puffinus Tavolara 2017). Beforehand, rat predation of eggs and chicks caused most nesting attempts to fail, with only 892 fledglings recorded in 2017 (BirdGuides 2019). Two years later, with no sign of any rats, the operation was declared a success, with the positive impact on Yelkouan Shearwater already evident in the form of 7,784 fledglings in 2019, representing a very significant boost to the species’s population and prospects of survival (BirdGuides 2019).

Third, the species’s estimated generation length has been improved and revised downwards, from 18 years to 13.6 years, using a method developed and applied to all the world’s birds (Bird et al. 2020). This brings it into close alignment with the congeneric Balearic Shearwater P. mauretanicus, and means that the relevant period for assessing trends over three generations under Criterion A is now 41 years, rather than the 54 years used previously, making it less likely to qualify as Vulnerable (in the absence of any evidence for an overall population decline exceeding 30% over 41 years).

Fourth, in late 2019, all 28 European Union (EU) Member States were obliged to complete their second 6-yearly report to the European Commission (EC) under Article 12 of the EU Birds Directive, including their latest information on the sizes and trends of the populations and ranges of all naturally occurring wild bird species. Under an EC contract to evaluate the EU population status of each species, BirdLife has attempted to analyse these new data, which together represent c. 95% of the species’s known global breeding population. Unfortunately, neither Italy (c. 50%) nor France (c. 10%) were able to report the species’s short-term population trend (since c. 2007) with any certainty, although a recent demographic model based on parameters from populations on three French islands (but excluding possible immigration) suggested an annual rate of decline of between -12.8 and -3.7% (Courbin et al. 2018). Greece (c. 30%) reported stability and Malta (c. 7%) reported an increase of 18%. Long-term population trends were also poorly known, although Italy reported an increase of 10–20% during 1993–2018, as well as both short- and long-term increases in the area of the species’s breeding distribution.

As the EU holds c. 95% of the global breeding population and range, the species’s EU status effectively determines its global status. Therefore, information is urgently sought about the current population trend of this species across its range, and especially in Italy. If there is no evidence that the species is declining overall at a rate exceeding 30% over three generations (41 years), then it will not be possible to sustain its classification as Vulnerable in the 2020 Red List. The successful eradication of rats from Tavolara, and island restoration efforts elsewhere in the Mediterranean, mean that the population-level impacts of invasive species are being reduced, with the consequent increased fledging success at least partly offsetting losses to bycatch and other threats. Taking a precautionary approach, it may be possible to suspect that the rate of decline in the next three generations due to exploitation (bycatch) and effects of introduced taxa may plausibly approach 30%, such that Yelkouan Shearwater could potentially be reclassified as Near Threatened under Criterion A3de.

Relevant comments and information on this fast-track topic are welcome by 8 April 2020, please.

Please note that this forum topic is not designed to be a general discussion about the ecology of the species, but rather a discussion of the species’s Red List status. Therefore, please ensure your comments are relevant to the species’s Red List status and the information requested. By submitting a comment, you confirm that you agree to the BirdLife Forums’ Comment Policy.


Bird, J.P., Martin, R., Akçakaya, H.R., Gilroy, J., Burfield, I.J., Garnett, S., Symes, A., Taylor, J., Şekercioğlu, Ç.H. & Butchart, S.H. (2020). Generation lengths of the world’s birds and their implications for extinction risk. Conservation Biology.

BirdGuides (2019) Yelkouan Shearwater bounces back on Tavolara. News: 20 November 2019.

BirdLife International (2015) European Red List of Birds: Yelkouan Shearwater Puffinus yelkouan.

Carboneras, C., Jutglar, F. & Kirwan, G.M. (2020) Yelkouan Shearwater (Puffinus yelkouan). In: del Hoyo, J., Elliott, A., Sargatal, J., Christie, D.A. & de Juana, E. (eds.) (2014). Handbook of the Birds of the World Alive. Lynx Edicions, Barcelona.

Courbin, N., Grémillet, D. and Besnard, A. (2018) Étude de la dynamique des populations de puffins de Scopoli et yelkouan du Parc National des Calanques et du Parc National de Port-Cros.

Gaudard, C. (compiler) (2018) Single International Species Action Plan for the Yelkouan Shearwater Puffinus yelkouan. Project LIFE 14 PRE/UK/000002. Coordinated Efforts for International Species Recovery EuroSAP. LPO/BirdLife France. Rochefort. 43p.

LIFE Puffinus Tavolara (2017) Eradication of Black Rats Rattus rattus from the island of Tavolara.

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19 Responses to Archived 2020 topic: Yelkouan Shearwater (Puffinus yelkouan) – request for information on population trends

  1. John Croxall says:

    Demographically, essential to use similar parameters to its sister-species, Balearic Shearwater. This makes it harder to meet VU criteria, especially in absence of recent input on Italian population status. If European experts accept the assessment presented, reclassification as NT seems inevitable.

  2. Pierre Yésou says:

    The estimated number of French breeders has increased recently (see national report to the European Commission under Article 12 of the EU Birds Directive), reflecting a better census coverage, change in methodology, and the positive effect of rat eradication from an important site. Further, there is evidence (initially from Zembretta, Tunisia) that immigration readily occurs once rat are eliminated, a positive fact weakening the negative feeling arising from recent demographic modelling. (Also, there is hope for the future: thanks to Conservatoire du Littoral, a national body for coastal conservation, rat eradication is planned on other French Mediterranean islands, which should lead to efficient results in a coming years). Considering this and the elements developped by BirdLife International, above, I agree with the proposed downgrading of the Yelkouan Shearwater to Near Threatened.

  3. Bruno Massa says:

    Being very difficult to census this species, many figures presently available from Italy are not reliable. The breeding population of Yelkouan Shearwaters in Sicilian waters is still vaguely known and the only known breeding sites are on the Egadi and Aeolian Islands, on Linosa and on Lampedusa with an overall estimated population of 500-800 pairs (MOLTONI, 1970; IENTILE & MASSA, 2008; MASSA et al., 2015). CORSO et al. (2009) reported numbers of breeding pairs on Lampedusa Is. much higher (between 2,000 and 4,000), but we were not able to confirm this estimated population, possibly due to different census approaches. The methodology used for counting rafting Scopoli`s cannot be deployed for Yelkouan Shearwaters due to the different behavior patterns. Thus, I believe that overall estimate of central Mediterranean population should be an over-estimation. In addition, among the 90,000 counted in the Bosphorus also young and immatures of different age must be included.

  4. Nicola Baccetti (ISPRA, Italy) says:

    Please allow me to say that all this looks like a sort of deja-vu from the course of the 2015 reassessment, increased by some degree of misunderstanding about the outcomes of recent management efforts. I’m writing with an Italo-centric perspective, which is quite relevant in terms of population size. Please also forgive my Covid homebound condition, which does not allow me to be as precise as I should be. I think the following points should be raised for a broader discussion.

    1) Decline at a rate of >30% over three generations. Figures to be used for this calculation should be cleaned from the effect of gradually improved data quality. Higher totals obtained in recent years may still hide a decreasing trend. This was a main point of the 2015 discussion. As a new piece of evidence, please consider also the apparently high mortality rate of breeders at Sardinian study plots, included in Gaudard’s SAP.

    2) Not reaching thresholds for Vulnerable under the population size criteria C and D1. I think that these can be misleading requirements in a species which has a very concentrated population (c. 50% in a single, tiny archipelago), since a local crash would badly affect the whole.

    3) Tavolara estimation at 9,600-13,000 pairs, or c. 36–46% of the global population. It should be checked whether these figures refer to Tavolara only (where rat eradication took place) or Tavolara archipelago, what is not possible for me to do in these weeks of strict Covid confinement. However, just for information, population data have been reviewed as recently as 2019 on the whole Sardinian (and French) range for the Girepam Interreg project. A new table is going to be available at the Env Ministry in 2 weeks as a part of a local AP, arranged island by island and improved since Gaudard’s.

    4) Reporting from Tavolara of only 892 fledglings in 2017 (BirdGuides 2019) and 7,784 after the rat eradication, “representing a very significant boost to the species’s population”. This is a basic estimation written by myself for a press release to let a broad audience get a feeling of i) the potential impact of the operation, ii) that its outcomes are being monitored, iii) that EU money was used for the reasons it had been given. The ridiculously precise values given above cannot be used as such without knowing how they were obtained. Morever, Tavolara breeding success has actually been disappointingly low after the eradication (around 0.5 if I remember correctly, i.e. not enough to allow pop stability, let alone any increase), when compared to previous Molara and Montecristo eradications.

    5) 41 years rather than 54 years as 3-generations length. Doesn’t make a big difference in this specific case, because most of reliable infos refer to the second half of the period.

    6) “neither Italy (c. 50%) nor France (c. 10%) were able to report the species’s short-term population trend”: right, indeed we weren’t. Because it’s very difficult. I wonder how Greece could, with 2000+ islands, whereas I can understand this can be more precisely assessed in the Maltese situation. About the supposed long term increasing population trend in Italy: same problem as for the 2015 assessment, i.e. effect of improved methods and alike. And again, “short- and long-term increases in the area of the species’s breeding DISTRIBUTION in Italy”: same explanation. Just by memory, but I think I remember the database quite well, there are no islands where the species didn’t certainly breed 30 yrs ago and it now does, there are a few which were abandoned (as was Corsica as a whole), and only one (Giannutri) which has been re-colonized after the rat eradication (3 pairs).

    7) “The successful eradication of rats from Tavolara, and island restoration efforts elsewhere in the Mediterranean, mean that the population-level impacts of invasive species are being reduced, with the consequent increased fledging success at least partly offsetting losses to bycatch…”. This is what I warmly hope, unless we are ‘buying years to extinction’, as a well known paper was titled. But even eradications are only a part of the game to be played on land, as biosecurity measures to prevent rat recolonization should be fully enforced, while at present they are not. I invite my colleague Paolo Sposimo to better evaluate the current situation at this regard, with a specific reference to the case of a fishing vessel crashing into Montecristo last year and to the sabotaged Molara eradication.

    8) “Taking a precautionary approach, it may be possible to suspect that the rate of decline in the next three generations due to exploitation (bycatch) and effects of introduced taxa may plausibly approach 30%…”. This might hold true in the optimistic case that all n=3 eradicated sites holding important populations (Tavolara, Malta and Montecristo) remain as such forever, or at least in the long term. As soon as rats return on one, should we upgrade the species again? I think that when the success of current policies relies on such a small number of sites, the worse one can do is changing the conditions which have allowed some instances of effective management to take place.

  5. Dear Nicola and dear all,
    the productivity on Tavolara has been extimated in 892 indd. (0,08 fledged/nest x 11.152, geometric mean of current estimation) in 2017 (last reproductive season before eradication), 4684 (0,42 fledged/nest) in 2018 and 7784 (0,698) in 2019. The low result in 2018 has been due to heavy rains and flooding of the nests during incubation and shortly after hatching.
    Therefore the effect of rat eradication on Tavolara has been great in these first 2 years, as for Malta (where there is a recurring rat control) and Montecristo, but currently the main uncertainity is: we’ll be able to maintain the islands rat-free status in the long term?
    Even without considering apparently improbable but still possible events, as the fishing vessel crashed into Montecristo (but in our rapid response and monitoring activities we have no evidences of rat presence) and the sabotaged Molara eradication, the risk of a rat reinvasion on Tavolara is unknown; I have planned as best I could the biosecurity measures that have been implemented, in next months we’ll do some improvements to them, but we don’t know their effectiveness, due to the scarce distance from mainland Sardinia (2 km with some islets potential stepping stones), the presence of military settlements and the arrival of a lot of tourists during summer months. On Malta, of course, I guess there is a risk of interrupting the localized rat control implemented every year, due for example to temporary lack of funding or to unpredictable events like Covid 19 restrictions.
    Moreover, in these last years we have some evidences that suggest the risk of a relevant “source-sink” effect, i.e. of a recruitment, of unknown importance, of new breeders “produced” in rat-free islands into “with-rat” islands, and of a consequent reduction of long-term positive effects of rat eradications on some of the main colonies respect to the global population.
    Taking a precautionary approach, in my view, we should better wait some more years (3-5?) to downgrade the YS classification, and possibly we should try to collect reliable data by other methods, like annual counts during the passage through Bosphorus.

  6. Marco Zenatello - ISPRA Italy says:

    I agree with all the comments by Nicola, and I would like to add a couple of additional considerations to the topic. In 2015 the summary conclusion of the debate had been “…to precautionarily retain the species’s previous listing as Vulnerable, while noting that if further study and monitoring provided evidence of large stable or increasing populations, the species’s status would be reviewed and may warrant reclassifying in the future.”
    I assume that, like Nicola and others already remarked, the issue concerning current vs past figures is not worth being re-discussed: at least for what Italy is concerned, in the last 10 years or more we have been dealing with population re-assessments and only in a negligible part with genuine numeric changes. The parameters which we should focus on to assess/understand YS’ conservation status should be (1) breeding success and (2) adult survival rate.
    1) Do we have data on breeding success which could reasonably suggest a self-sustaining population? I would rather say that – as far as Italy is concerned – what we currently have is a short-term series of data showing that in areas where predation by alien species has been removed, the breeding success can burst up to 0.93/0.96 in good years. Such values should guarantee population stability and perhaps, if they remain high for some (several?) years, they will favour a recovery of the breeding population. As of now we have <700 breeding pairs (Montecristo) “safe” since 2012 and ca. 10-13000 bp (Tavolara + Cavoli) since 2018. Mission accomplished! But since the last two (2!) breeding seasons! Let’s see what happens next (maybe not for the duration of a generation, but at least for “some” years) before saying that troubles are over…
    2) Despite the paucity of available data, adult survival rates observed so far in Italy and France (Gaudard 2018) are well below the safety threshold, for reasons still unknown but likely not related to rat predation. Samples are small, but all point to values well below 0.9…
    Do we have evidence of large stable or increasing populations to-date?
    A parallel discussion is active on the “sister” Balearic shearwater: one important issue raised in comments is that downgrading a species’ status is a massive step in terms of conservation, to be accurately evaluated though sound (and agreed) data.

  7. Steffen Oppel says:

    The LIFE project on Malta (run by Dilek Sahin and Martin Austad at BirdLife Malta) has provided some additional data since 2016 on adult survival and breeding success, but there is a lot of annual variation and uncertainty. However, thanks to the conservation efforts (reducing disturbance and controlling predators) there appears to be a genuine improvement in breeding success and also adult survival. The recent counts on Malta are also slightly higher than historic assessments. We do not know whether the improved estimates are a result of better methods or an actual biological improvement. The key problem for this species (and probably for Balearic Shearwater) is that there are no robust long-term abundance and trend data, so anything is always subject to speculation and interpretation.

    However, with the recent data we have – and acknowledging the massive uncertainty in improvement of counts and generally not know how many there are – there is in my opinion no valid justification (other than ‘we are worried’ – but we are worried about everything!) to keep this species ‘Vulnerable’. The massive uncertainty is reflected in the proposition to downlist to ‘Near Threatened’ (rather than ‘Least Concern’). We may not have hard evidence for a major population increase, but we also don’t have evidence for a major population decrease, which – given the abundance and range of the species – would be required to list it as globally threatened.

    As I pointed out for Balearic Shearwaters, it would be good to consider these two species together and ensure that any status change assessments are consistent.

  8. Dilek Sahin, BirdLife Malta says:

    Below comments are posted on behalf of BirdLife Malta and in two parts as the text is too long to submit in one comment.

    There have been research efforts on the species since the last status evaluation. In the case of Malta, EU funded LIFE Arċipelagu Garnija Project (LIFE 14 NAT/MT/991) has conducted extensive colony research, all around the Maltese Archipelago and updated the breeding population size by combining the results with the estimates obtained by John Joseph Borg (Borg, 2017). The results were reported by the Maltese government under Article 12 in 2019, however, apparently with misinterpretation of the reasons for the reported increase. Such an increase is mostly a result of improved knowledge of colony size and distribution and should not be interpreted as a genuine increase for the given period. And similarly, for the given period the short-term trend of the species in Malta is stable and not increasing. As an example, at L-Irdum tal-Madonna colony population estimates between 2016 and 2018 (375 – 600 breeding pairs) do not differ substantially from the 2009 estimates (398 – 602 breeding pairs) (Borg, Raine, Raine, & Barbara, 2010). This colony is the only one for which nest site knowledge and monitoring has been sustained at a very high level since 2007 thanks to EU LIFE projects (LIFE10 NAT/MT/090 and LIFE06 NAT/MT/097). If this colony is taken as a reference, even being the focus of conservation efforts including long-term rat control started in 2007, the population has not increased post rat control initiation. Therefore, it is likely that inaccessible colonies are experiencing long-term population declines as they do not benefit from direct conservation actions. Now the current estimates from J.J. Borg and BirdLife Malta’s LIFE funded seabird projects establish the baseline for breeding population estimates at well-monitored colonies. Any future estimates obtained using similar methods at these colonies when compared to this baseline should reflect a more reliable trend.

    There has been also more conservation effort on the species since the last status evaluation. LIFE Arċipelagu Garnija Project has been implementing rat control programme at six colonies in Malta and the results indeed show an increase in reproductive success (rate of increase ranging from 18% to 76% in 2 years after rat control, unpublished data), although at some colonies it is still not as high as the targeted value (0.75) in the Species Action Plan (Gaudard, 2018). Moreover, there is annual variation in reproductive success at some colonies, indicating that there might be other terrestrial and/or marine threats influencing this rate at the breeding colonies. It should also be noted that complete eradication of rats is unfeasible in any Yelkouan Shearwater Maltese colony, and therefore the reproductive success highly depends on the continuous rat control effort, which is not the case for after 2020 (e.g. future funding and resources have not secured yet). Increased reproductive success in Malta and in other archipelagos following predator management is surely helping the global population’s persistence, however, throughout the Mediterranean, we still have no or very little information on the survival rates of the fledglings and recruitment by maturation or by immigration at colonies, as well as the impact from other major threats like fisheries bycatch and light pollution on both young and adult birds. For example, light pollution is a growing concern for the survival of fledgling seabirds and not being monitored well in all of the countries hosting major Yelkouan Shearwater colonies.

    Using capture-mark-recapture data collected at four main colonies in Malta between 2012 and 2019, during LIFE+ Malta Seabird and LIFE Arcipelagu Garnija Projects, we recently calculated the annual adult survival rate of Yelkouan Shearwaters as higher than 0.70, showing high annual variation (Environment and Resources Authority, 2020). Survival rates between 2012 and 2019 (except in 2018) are lower than the target given in the species action plan (0.92), and the contribution of fisheries bycatch to this rate is not well known for the Maltese Yelkouan Shearwater population. Currently, seabird bycatch data is being collected through electronic logbooks by the Government, based on voluntary reporting. The species has also a wide foraging range within other fisheries zones in the Mediterranean, possibly contributing to such a threat.

    • Dilek Sahin, BirdLife Malta says:

      Following the publication of the Species Action Plan, there has been little effort in closing the knowledge gaps in the Eastern Mediterranean. BirdLife Turkey had recently (2019) started a MAVA funded project to identify at-sea distribution and abundance of species and conducting colony research at a couple of sites, but the fieldwork has stopped at an early stage due to COVID-19 outbreak. The systematic bimonthly Bosporus counts were carried out for four years and stopped in 2014, before the previous status evaluation, so it is not possible to compare the yearly totals as a (relatively) standard monitoring for the last five years. Furthermore, the results of these counts should be evaluated cautiously. According to available information, the timing of the survey (February 2014), where 90.000 individuals were counted is showing that this figure includes non-breeding individuals. However, a calculation based on a very vague and simple population model showed that this figure might also be indicating some undiscovered breeding colonies in the Eastern Mediterranean (Sahin & Oppel, 2016). Regardless of the species’ status the effort in colony research should be increased in the Eastern Mediterranean countries.

      While acknowledging the increased conservation efforts with positive outcomes and increasing effort in research in some countries, we think there are still key knowledge gaps on the species (i.e. distribution, abundance and the impact of main threats) in the Mediterranean and apparently inadequate amount of good quality survey data from known major colonies (e.g. Italy), which hinders a clear conclusion that the species is not declining in the Mediterranean. Therefore, as a precautionary measure, the current VU status should be retained until the next evaluation period, ideally with increasing initiatives to support/urge countries to close these key gaps and better quantify the results of conservation efforts by utilising the available expertise on the species.

      Borg, J J, Raine, H., Raine, A. F., & Barbara, N. (2010). Protecting Malta’s wind chaser: the EU life Yelkouan shearwater project report., 1–31.

      Borg, John J. (2017). Interpreting pelagic seabird population numbers in the Maltese Islands. Avocetta, 41(1), 1–4.

      Environment and Resources Authority, E. (2020). Update on Articles 8, 9, and 10 of the Marine Strategy Framework Directive (2008/56/ΕC) in Malta’s Marine Waters.

      Gaudard, C. (2018). Single International Species Action Plan for the Yelkouan Shearwater Puffinus yelkouan.

      Sahin, D., & Oppel, S. (2016). High migration counts in Turkey suggest the existence of undiscovered colonies of the Yelkouan shearwater. Edinburgh: 13th International Seabird Group Conference, 6-9 September 2016.

  9. Sven Kapelj says:

    This species is very difficult to monitor so it’s no wonder that there are gaps in understanding its trend.
    In case of Croatia, we had put quite an effort in the last years to determine its status and range on national scale and to conserve some of its major known colonies. At this moment we can argue that Yelkouans have lost part of their breeding range in Croatia, since some of historic colonies that had breeding birds recorded in 2010., seem to be abandoned now. Some other colonies remain to be re-assessed. All islands and islets with Yelkouan colonies in the Adriatic are infested with rats.
    On example of island of Zaklopatica which is well known colony where we did conservation effort (rat removal), we have recently recorded an increase in number of breeding pairs, most likely due to higher mobilization of adult birds that would otherwise abandon the site upon prospecting. Since we’ve only just begun proper monitoring and conservation, it will take few more years of constant effort monitoring to be able to determine any kind of trend.
    Conclusion on our national population so far is that the species is highly conservation dependent and will remain such until we permanently secure their breeding grounds with extensive rat eradication programs. In any case, Croatian population with current (probably underestimated) number of 300-400 breeding pairs is certainly not a major factor in determining their global status. If I understood correctly, neither Italy nor France, holding together estimated 60% of global population, couldn’t determine species’s population trend with certainty so I would be cautious about down listing this species.

  10. Danae Portolou (Hellenic Ornithological Society) & Jakob Fric (NCC) says:

    The Hellenic Ornithological Society (HOS) has been performing population census work in the Aegean and Ionian Seas since 1995, through the implementation of various LIFE projects and the financial support of the A.G. Leventis Foundation. Overall, 17 colonies have been located (some comprising of numerous islets), reaching an estimated population of 6,830 – 13,200 bp (HOS unpublished data 2019, Gaudard 2018). The population estimate provided during the previous Art 12 Reporting of 4,000-7,000 bp (Fric, et. al 2012, Portolou, et al. 2009) did not take into account the largest Greek colony, Gyaros island, which was only first discovered in 2014. Gyaros colony is currently estimated at 3,570 – 7,350 bp, corresponding to 45.2 – 56.5% of the national population, 14.6 – 20.7% of the global population and 14.5 – 21% of the EU population respectively (Gaudard et al. 2018, Fric et al. 2012, BirdLife International 2017). Nevertheless, this estimation is considered conservative and there is a great possibility that the population is even larger (Fric et al. 2019). The colony has been monitored since 2014 on an annual basis by HOS, in collaboration with Nature Conservation Consultants, and this will hopefully continue if funding is secured. Rat predation of eggs and chicks has been shown to be the most important threat for the species on Gyaros (Fric et al. 2019) affecting approximately 33% of monitored active nests. Breeding success has been estimated to be much lower (0.15 – 0.56 chicks/pair) than the targeted value in the Species Action Plan and in comparison to other Mediterranean colonies (Fric et al. 2019, HOS unpublished data). Due to its large size (1780ha) rat eradication actions on Gyaros are expected to be very costly and challenging logistically. Rat control could be implemented in the core of the colony but funding should be secured. Finally, over the last 4 years, a stable decrease in nest occupancy is observed.

    Our opinion with respect to the current discussion is that by no means has the species population in Greece showed an increase and that the increase in population size relates to greater survey effort and better methods used. We do not have robust data on population trends, but a decline is suspected (Gaudard et al. 2018). Since systematic monitoring is not performed currently in any other colony in Greece, we cannot be sure how other colonies are doing. However, 5-year data from accessible nests in Gyaros island suggest that the colony is not doing well, mainly due to predation but perhaps other threats which are not evaluated. By-catch has been reported in the wider area of Gyaros island, as well as in other parts of the Aegean Sea, but its extent and impacts on the population cannot be estimated from the available data.

    We believe that it would be precarious to downlist a species for which there are still major gaps and monitoring is so difficult, thus any population change will not be evident easily and quickly in order to take action. From a conservation point of view, in Greece, one of the key breeding and migratory areas for the Yelkouan Shearwater, no major pressure mitigation measure or environmental change that would directly benefit the species has taken place recently that would change its conservation status. Therefore, we consider that a conservative approach should be taken in assessing the species status, In addition, prior to downgrading it, it should be confirmed that there is no significant population decline and that major factors which could lead to such decline e.g. predation of invasive species or bycatch in short term have been sufficiently mitigated. At the national level none of these can be claimed. Therefore in our view, Yelkouan Shearwater should retain the Vulnerable status as a precautionary measure at least up to the next Art12 reporting period.

    Fric, J., Portolou, D., Evangelidis, A., Dimalexis, A., Papadas, C. & Nikolaou, I. (2019). Yelkouan shearwater population study at the island of Gyaros. Compilation report 2015-2018. Nature Conservation Consultants (NCC) Ltd & Hellenic Ornithological Society.[In Greek]
    Fric, J. &D. Portolou (2016). Yelkouan shearwater(Puffinus yelkouan) population study at the island of Gyaros. Annual Report 2015. Nature Conservation Consultants (NCC) Ltd. & Hellenic Ornithological Society [ In Greek].
    BirdLife International (2017). European birds of conservation concern: populations, trends and national responsibilities. Cambridge, UK: BirdLife International. ISBN 978-1-912086-00-9
    Gaudard C. (compiler) (2018). International Single Species Action Plan for the Yelkouan Shearwater Puffinus Yelkouan. Project LIFE 14 PRE/UK/000002. Coordinated Efforts for International Species Recovery EuroSAP. LPO/BirdLife France. Rochefort. 45p.
    Fric, J., Portolou, D., Manolopoulos, A. & T. Kastritis. 2012. Important Bird Areas for Seabirds in Greece. LIFE07 NAT/GR/000285 – Hellenic Ornithological Society (HOS/BirdLife Greece), Athens
    Portolou, D., Bourdakis, S., Vlachos, C., Kastritis, T. and T. Dimalexis (eds.) (2009) Important Bird Areas of Greece: Priority sites for conservation. Hellenic Ornithological Society, Athens.

  11. Please see my comment for Balearic shearwaters, which applies in the same way to the Mediterranean shearwater, but here I adapted the most important part:

    The Mediterranean shearwater is one of the seabirds most affected by by-catch in longlining, in particular demersal longlining in the Western Mediterranean. Current levels of by-catch are most likely unsustainable but basically are largly unknown unknown and, most importantly, are very likely to be largely understimated. In this regards, I would like to briefly summarize some of the information we have recently reviewed for the General Fisheries Commission for the Mediterranean (GFCM), since this has not yet been published. We used records of incidental catches of seabirds presented derived from different approaches, including monitoring programmes with onboard observers, but also from non-systematic, opportunistic data collection such as questionnaire surveys with fishers, tagging/ringing-recovery programmes of seabirds, personal comments of scientists, self-sampling by fishers, beach surveys or recoveries from rescue centres. I would like to highlight two main points:

    Uncertainty in by-catch due geographically uneven records: Overall, the data available on seabird bycatch in fisheries of the Mediterranean and Black Sea are not only scarce, but also unequally distributed. No records could be found for the Black Sea and from African Mediterranean countries. Records from the Western Mediterranean Sea derived from Italy (6.9 percent), and especially from Spain (63.3 percent), where the only known study with regular data collection of seabird bycatch over a long time period (2000–to date) is conducted. This means that Mediterranean shearwaters may be caught in many countries of the Mediterranean and the Black Sea for which there are no records because there is hardly no one recording bycatch.

    Uncertainty in the fishing effort of the small-scale fisheries: Most by-catch events of Mediterranean shearwaters is mainly recorded in small scale longline fisheries. Unfortunately, small-scale fisheries use relatively small boats from 6 to 15 m and therefore many of them are below the length for which positioning systems are mandatory. This implies we cannot estimate the number of birds caught because we do not have a good record of the fishing effort of the small-scale fisheries. It is urgent now to improve the methods for recording fishing effort and incidental catch, particularly in small-scale fisheries.

    Both points mean current estimates of by-catch numbers possibly are a gross underestimation of the reality.

    Until the European Union and the state members as well as the other countries with substantial numbers of Mediterranean sheawaters foraging in heir waters:

    (1) do not solve uncertainty in by-catch rates
    (2) do not solve uncertainly in the fishing effort of small-scale fisheries
    (3) do not force real implementation of mitigation measure for by-catch in all countries

    -> the Mediterranean shearwater should not be downlisted.

    Wolf Isbert, Vero Cortes and Jacob Gonzalez-Solis. Seabirds in Carpentieri P., Nastasi A., Sessa M., Srour A. eds. 2020. Incidental catch of vulnerable species in Mediterranean and Black sea fisheries: a review. Studies and Reviews n. 101. Rome, FAO. (Forthcoming)

  12. Bourgeois Karen says:

    The estimate of the Yelkouan shearwater breeding population has recently increased in France (from 627-1044 breeding pairs based on censuses carried out in 2004-2010 to 2031-4424 breeding pairs in 2017-2019). This is mainly due to a change in the census methodology on Le Levant Island and to a lesser extent due to the discovery of colonies in an up-to-now not explored habitat on this island which hosts about 90% of the French population. In 2007-2009, 384-641 pairs were estimated to breed on the island by censusing occupied and apparently occupied burrows on 40% of colonies identified and then extrapolating the numbers obtained to the remaining colonies. In 2018, 1811-4059 pairs were estimated to breed on the island by estimating burrow density and occupancy using random sampling and quadrants (92 of 200 m2 on average) within suitable habitats (including the newly discovered habitat) and then extrapolating to the total area of suitable habitats. Thus, this definitely does not indicate an increase in the population size. By contrast, predation by feral cats is the highest on Le Levant Island among the Hyères archipelago (Bonnaud et al. 2015) and is responsible for the yearly death of about 810–3241 yelkouan shearwaters (Bonnaud et al. 2012). The yelkouan shearwater population on Le Levant Island cannot withstand such a predation pressure even if most individuals killed by feral cats are non-breeders and/or immigrants. Indeed, the most optimistic model indicates a population decline of 14.79% per year. We should run again population models entering the new population estimates but it is highly probable that the results would be similar, i.e. annual population decline > 10%. On Porquerolles Island (Hyères archipelago), the yelkouan shearwater population was estimated at 66-121 breeding pairs in 2004-2006 and 36-79 breeding pairs in 2016. This corresponds to a decline of 35-45% in 10 years. This supports population declines indicated by population models even if the rate of decline seems to be lower than the ones inferred by models (6% annually in Oppel et al. 2011, >12% annually in Courbin et al. 2018). On Porquerolles Island, predation by feral cats is the lowest among the Hyères archipelago (Bonnaud et al. 2015) but is probably sufficient to threaten population viability. Yelkouan shearwater breeding success has also been quite low on this island (51±15% on average in 2003-2014) mainly because of predation by black rats. The breeding population on Port-Cros Island (Hyères archipelago; 148-245 breeding pairs in 2004-2006) was censused in 2019 but results are not published yet impeding a comparison with predictions by population models (-6% per year in Oppel et al. 2011, -7.5% per year in Courbin et al. 2018). However, the breeding population on this island seems to decline despite feral cat eradication. The breeding population on Marseille islands has been stable for 10-15 years with 30-40 breeding pairs ( 30% over 41 years.

  13. Bourgeois Karen says:

    Contrary to what P. Yésou indicated, no rat eradication has been undertaken on any French important breeding site (which would have been in the Hyères archipelago). Even if such an eradication had been performed, breeding success is not the most important demographic parameter for shearwater population dynamics, contrarily to adult survival. On Hyères islands, particularly Le Levant Island, the main threat to Yelkouan shearwater breeding populations is predation by feral cats. Rat eradication on Tavolara Island is a great achievement that was necessary for yelkouan sheawater population conservation but once again it is essential to reduce adult mortality to insure population viability. N. Baccetti indicates high breeder mortality in Sardinia. This is an issue that should be urgently clarified. In addition, at-sea mortality is suspected to be high for this species although it could be irregular (low bycatch rate on average but several tens or hundreds individuals bycaught in one event; Cortés et al. 2017) making this threat even more difficult to estimate.
    Considering data for France as exposed above and comments by B. Massa, N. Baccetti, P. Sposimo, M. Zenatello, D. Sahin, BirdLife Malta and S. Kapelj concerning data for Italy, Malta and Croatia, I would recommend, as a precautionary measure, to maintain the current VU status of the Yelkouan sheawater at least until the next evaluation period to allow further and more precise data collection on population trends and a better evaluation of the effects of conservation actions.

    Bonnaud E., Berger G., Bourgeois K., Legrand J., Vidal E. 2012. Predation by cats could lead to the extinction of the Mediterranean endemic Yelkouan shearwater Puffinus yelkouan at a major breeding site. Ibis 154, 566–577.
    Bonnaud E., Palmas P., Bourgeois K., Ollier S., Zarzoso-Lacoste D., Vidal E. 2015. Island specificities matter: cat diet differs significantly between islands of a major breeding archipelago for a vulnerable endemic seabird. Biol Invasions 17, 2927–2941 (2015).
    Cortés V, Arcos JM, González-Solís J (2017) Seabirds and demersal longliners in the northwestern Mediterranean: factors driving their interactions and bycatch rates. Mar Ecol Prog Ser 565:1-16.
    Oppel S., Raine A.F., Borg J.J., Raine H., Bonnaud E., Bourgeois K., Breton A.R. 2011. Is the Yelkouan Shearwater Puffinus yelkouan threatened by low adult survival probabilities? Biol. Conserv. 144: 2255–2263.

  14. The following is a contribution to this forum on behalf of SEO/BirdLife.

    This is a species in a similar situation to that of the Balearic shearwater (BS), also discussed in the current revision process. Demographic parameters are similar, if better assessed in BS. And the main threat is arguably the same, bycatch, which is largely unassessed throughout the distribution range of YS. The main difference between the two species is that BS has a smaller breeding range, and a smaller population. But considering similarities, a negative population trend is expected, and likely driving the species to a decline of more than 30% in 3 generations (now re-assessed at 41 years). Again, a proper process of discussion is missing here.

    The main change for the conservation of YS since 2015 assessment is the reduction of population-level impacts of invasive species, principally in Tavolara. Other rat free colonies or with annual rat control (e.g. Malta) provide comparatively little benefit to the species, given their smaller breeding populations.

    But the main threat, bycatch in fishing gear, identified in the SAP (Gaudard 2018) has not changed as far as we know. To our knowledge there has not been any significant conservation effort to tackle this threat along the Species’ distribution range since 2015 (nor before). Even if breeding success has increased in large colonies, for a long-lived species with low productivity as YS, adult survival (largely affected by bycatch) is the most important population parameter that should be increased to ensure the Species’ population in the long term.

    This should be taken into account seriously to assess the species situation before downlisting it to NT. It is speculative to assume that the increased fledging success in Tavolara and other sites partly offset losses to bycatch and other threats in a level that change substantially the situation from last assessment without providing evidence of it. Moreover, despite the importance of Tavolara, there is still a large fraction of colonies where control of predators has not been conducted.

    A precautionary approach if there are not new evidences would be to keep the Species in the current VU status. In the 2015 assessment the recommendation was to adopt the precautionary principle and hold the status of the YS as VU, at least until a proper population viability analysis is conducted, considering information from a diversity of colonies throughout the species’ range. This population viability analysis has not been conducted yet.

    (to be continued)

  15. We will make a few comments in the 4 points showed in the assessment:

    1. The Species Action Plan (SAP) (Gaudard 2018) in fact highlighted the most critical threat affecting the species as bycatch. This threat is largely unstudied in all the species distribution range, being unknow how it affects to the main colonies in Italy, Malta and Greece. SEO/BirdLife is currently assessing bycatch in the Spanish waters in the Western Mediterranean and new efforts are ongoing or planned in at least Spain, Malta and Greece, but it is still early to have a full picture of the threat.

    The most recent studies available in Spain show worrying numbers of YS bycaught in the Western Mediterranean (Catalonia) (Cortés et al. 2017, Tarzia et al. 2017). In the latter study, in Spring 2017 we collected information of 657 shearwaters captured by 13 small-scale demersal longliners, during a 3-month period (peak time o bycath), using self-reporting logbooks. Relying on birds brought to port plus tentative identification by fishermen, almost half of them were YS, estimating 293 birds. This is only an example, from a small pilot study, in a small portion of the distribution range of the species, but should highlight how relevant bycatch may be.

    2. The success of rat eradication in Tavolara is indeed very important to increase the breeding success and in the medium-long term the Species’ population, but it is arguable if this happens in the short term and in the time of this new assessment. Tavolara is officially rat free only since the end of 2019 as Nicola Baccetti and Paolo Sposimo explained (2 years after rat eradication). First, it should be ensured in the coming years that the island remains rat free, and second, at least till 3-4 years time will not be possible to know the number of fledglings recruiting in the colony and translated into an increase in the breeding population. Therefore, the effects of this successful conservation effort on the population level should be taken cautiously and wait few years as Paolo suggest before to down list the species.

    3. The new generation length of 41 years instead 54 makes indeed less likely to qualify as Vulnerable, but there is not new evidence to confirm or reject this fact. If there is not any evidence for an overall population decline exceeding 30% over 41 years as a precautory principle to protect the species it should be kept in the current status rather than downlist it without evidence that the species is not declining any more at that level. The available demographic information on the species, though scattered, suggest adult survival rates (the most sensitive parameter) comparable to those of the Balearic shearwater, and this should be taken into account, as a sharp decline of 14% per year has been estimated for that species (and other similarities in demographic parameters are expected).

    4. The information presented shows that the reported data by European Union (EU) Member States did not clearly show new data to assess properly the short and long-term population trend. This highlights again the need to conduct a population viability analysis.

    Quoted references:
    Cortés, V., Arcos, J. M. & González-Solís, J. 2017. Seabirds and demersal longliners in the northwestern Mediterranean: factors driving their interactions and bycatch rates. Marine Ecology Progress Series 565: 1-16.
    Gaudard, C. (compiler) (2018) Single International Species Action Plan for the Yelkouan Shearwater Puffinus yelkouan. Project LIFE 14 PRE/UK/000002. Coordinated Efforts for International Species Recovery EuroSAP. LPO/BirdLife France. Rochefort. 43p.
    Tarzia, M. (compiler), Arcos, P., Cama, A., Cortés, V., Crawford, R., Morkūnas, J., Oppel, S., Raudonikas, L., Tobella, C., Yates, O., 2017. Seabird Task Force: 2014-2017. Technical report.

  16. Red List Team (BirdLife International) says:

    The following comment is posted on behalf of Jula Selmani (National Agency of Protected Areas, Albania:

    Yelkouan Shearwater, is a sea bird that is commonly seen around 1 mile away from the coast of Albania, along the entire coast of the country. Along the migration seasons sometimes flocks of nearly 100 birds have been observed (Iliev et al 2016). There are not yet evidences that the bird is nesting in Albania. However, no monitoring of the suitable habitats has been carried out yet. Therefore, as a breeder, considering the small area of occupancy (equal to suitable habitat to breed in Albania) the species should be classified as “EN” under the B criteria (B2). In addition, if it breeds in Albania, we estimate that it should have a small population less than 250 mature individuals, thus, it classifies as “CR” under the criteria “C” and likewise “EN” under the criteria “D”.
    The status of the species in Albania we estimate to be “EN”.

  17. Red List Team (BirdLife International) says:

    Many thanks to everyone who has contributed to this discussion over the past 10 days. We realise that the window for consultation was short (and is now closed), and greatly appreciate the time and effort invested by so many people in commenting, especially during this unprecedented time globally. The volume and variety of responses received on this (and other) species means that it will take us several more days to digest, analyse and interpret everything. We will however do so as quickly as possible, posting our considered conclusions on this species’s status on this page in a final contribution by mid-April.

    Thank you once again, and Happy Easter.

    BirdLife Red List Team

  18. Red List Team (BirdLife International) says:

    Following careful review and consideration of the existing available information, as well as the new information and valuable views shared through the consultation above, we have now reached a decision on the status of this species for both the 2020 global Red List and the EU Red List of birds. Our conclusion is that this species should be precautionarily classified as Vulnerable (A4abcde) – retaining its current global classification (rather than reclassifying it as Near Threatened as originally proposed), and adjusting its EU status since it was last assessed as Least Concern at EU level in 2015.

    In making this decision, we have endeavoured to take as consistent an approach as possible with that applied to Balearic Shearwater P. mauretanicus, acknowledging that there are many similarities between these two closely related Mediterranean species. For example, both are long-lived, difficult to study and monitor (as shown by the large discrepancies between population estimates based on colony counts and passage counts), and known to be impacted by bycatch at sea and invasive predators at some colonies. Both are also high priority species for conservation, being listed on Annex I of the EU Birds Directive and numerous other multilateral environmental agreements for many years now, and thus eligible for resources (e.g. EU LIFE funding) that many species are not.

    The discussion topic above repeated a sentence from the current Red List rationale: “If further study and monitoring provide evidence of large stable or increasing populations, the species may warrant downlisting in the future”. Several respondents misinterpreted the current lack of evidence for overall population stability or increase as a reason for maintaining the status quo, which is neither the intention of nor compatible with the IUCN Red List Guidelines. The 2020 revision to the Red List assessment will clarify what is actually meant: that if there is no evidence of an overall population decline approaching (Near Threatened) or exceeding (Vulnerable) a rate of 30% over three generations when it is next assessed, then this species will warrant reclassification as Least Concern.

    Yelkouan Shearwater is known to have undergone recent and historical colony extinctions on multiple islands, be experiencing relatively low adult survival (owing mainly to bycatch) and low breeding success (owing mainly to invasive predators) in at least some colonies, and thought to be ‘conservation dependent’ on measures in a number of others. Furthermore, as the Species Action Plan was only recently compiled and published (2018), there has arguably been relatively little time to start implementing the key actions required to address the main threats identified (although this argument is weakened by its global classification as Near Threatened or Vulnerable since 2008).

    On this basis, it is possible to justify a one-off exceptional extension to the existing precautionary classification of this species’s status as Vulnerable, despite the current lack of evidence for an overall population decline. However, this possibility is finite. If no overall population reduction is evident and the same situation (in terms of data) pertains when it is next reassessed, then this species will likely have to be reclassified as Least Concern. Otherwise, IUCN could reject the assessment, as it would not satisfy the requirements of the Red List Guidelines. Note that it is not necessary to conduct a Population Viability Analysis (or equivalent quantitative analysis of the probability of extinction; Criterion E), as assessment against Red List Criteria A to D is more than adequate. IUCN’s requirements for applying Criterion E are both specific and extensive, which is why so few taxa (and no bird species) are currently evaluated using it.

    We therefore encourage all relevant parties and stakeholders to redouble their efforts and to collaborate more closely than ever on this species’s conservation, research and monitoring in the next few years, in line with the Species Action Plan. This includes resolving the discrepancy between the colony counts and passage counts in the Bosphorus, but especially increased monitoring of breeding population size and trends at colonies (alongside adult survival and breeding success). The aim should be to reach broad consensus on reliable, comparable national population size estimates and trends, in time for the next round of Article 12 reporting in 2025. Those data will form the basis of the next reassessment of this species’s Red List status in 2026, and provide valuable information to assess the effectiveness and impact of measures taken to implement the Species Action Plan.

    Many thanks once again to everyone who contributed to the discussion above and helped to inform this outcome. The 2020 Red List update for birds including this assessment will be published on the BirdLife and IUCN websites in December.

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