Archived 2018 topic: Northern Bald Ibis (Geronticus eremita): downlist from Critically Endangered to Endangered?

This discussion was first published as part of the 2017 Red List update. At the time a decision regarding the status of several was pended, but to enable potential reassessment of these species as part of the 2018 Red List update this post remains open and the date of posting has been updated.

Northern Bald Ibis, Geronticus eremita, is currently listed as Critically Endangered under criterion C2a(ii) on the basis that the species has undergone a long-term decline and now has an extremely small population, with >95% of wild birds in one subpopulation (BirdLife International 2017). This subpopulation is located in Souss-Massa National Park and Tamri, Morocco, where the population numbered 59 pairs in 1998 after 40 individuals died mysteriously in 1996 (Bowden 1998, Touti et al. 1999), but this has increased and is now relatively stable, with 116 breeding pairs present in 2015 (Latifa et al. 2016, Oubrou and El Bekkay 2015). A semi-wild population exists in Turkey, but because this population is managed and not truly wild, they are not included in an assessment of this species’s status. A tiny colony of 7 individuals was discovered at Palmyra, Syria in 2002 (Serra et al. 2004), but this subpopulation has dwindled with only one individual returning to the colony in 2013 and 2014; and no individuals in 2015 (Serra 2015), although since then one individual has been reported in Ethiopia which likely represents an individual that has migrated from Syria (C. Bowden pers. comm. 2017). The current situation in Syria makes monitoring very difficult, but it is likely that it is now extinct as a breeding species there (BirdLife International 2017). Re-introductions of this species have occurred in the Alps and Spain, with the latter holding a small number of independent, breeding individuals. Therefore, despite the decline in Syria, thanks to the growth and recent stability of the Moroccan subpopulation and the potential presence of a second wild population in Spain, the species likely no longer qualifies as Critically Endangered.

Focussing on Morocco, the main threats to the species there are illegal building and disturbance close to breeding cliffs and changes in farming on the feeding grounds. A proposed tourist development at the Souss-Massa National Park could also prove detrimental to the birds if it is not constructed in a sensitive way (Anon. 2009), though the most recent causes of breeding failure at this site have been loss of eggs to predators and, more importantly, poor chick survival as a result of starvation and predation (Bowden et al. 2003). Despite the presence of these potential threats around the Moroccan subpopulation, the number of breeding pairs has remained stable over recent years and the total number of individuals continues to grow (443 individuals at the end of 2013 breeding season [Oubrou and El Bekkay 2013]; 524 individuals in 2014 [Oubrou and El Bekkay 2014]; and 580 individuals at the end of the 2015 breeding season [Oubrou and El Bekkay 2015]). The most recent population size estimate (referring to the number of mature, breeding individuals) is 116 breeding pairs, which equates to 232 mature individuals.

There are two introduced populations in the Alps, totalling 30 individuals, in Burghausen (Germany) and Salzburg (Austria) (Wald 2014). These birds have undertaken human-led migration to Orbetello Lagoon in Tuscany, Italy and in 2011 the first bird independently migrated from Italy to Burghausen (Waldrappteam 2014a). A further colony is to be established at Uberlingen (Germany) (Waldrappteam 2014b). However, because of the continued management of these populations, they are not included as part of this assessment. With continued success and removal of management they may be included in future assessments.

The reintroduced population in southern Spain is more independent, and potentially could be included in an assessment of this species’s status. This population was set up to be more sedentary than the Alpine re-introductions, although interestingly individuals from this population have been observed crossing into Morocco (Muñoz and Ramírez 2017). A total of 190 birds were released in southern Spain between 2004 and 2009 (Boehm and Bowden 2010), and population supplementation continues (C. Bowden in litt. 2016). Although juvenile mortality has been high, the first breeding pair was formed on nearby cliffs in 2008, and a small independent non-migratory colony is now becoming well established in the area (Matheu et al. 2014). Up to a total of 24 breeding adults were present in 2013 on three separate cliffs (Jordano and Márquez 2013) and 25 breeding pairs were present in 2014 (UvA Bird Tracking System undated).

This equates to 50 mature individuals, which (combined with the Moroccan population) would give a global population size estimate of 282 mature individuals. However, given that the establishment of the wild, breeding population in Spain is only very recent, it is suggested that the global population size be conservatively retained in the range of 200-249 mature individuals. Therefore, it is proposed that the species be listed as Endangered under criterion D.

We welcome any comments or further information regarding this proposed downlisting.

 

The presentation given at the 2nd Meeting of the AEWA Northern Bald Ibis International Working Group can be found here: NBI Red List presentation

 

References

Anon. 2009. Bald Ibises – update. RSPB Legal Eagle: 16

BirdLife International. 2017. Species factsheet: Geronticus eremita. Downloaded from http://www.birdlife.org on 13/03/2017.

Boehm C. and Bowden C.G.R. 2010. Northern Bald Ibis Conservation and Reintroduction workshop. Proceedings of 3rd Meeting of International Advisory Group for Northern Bald Ibis (IAGNBI), November 2009. Palmyra, Syria.

Bowden, C. 1998. Birecik: the current situation of the semi-wild Bald Ibis Geronticus eremita population.

Bowden, C. G. R.; Aghnaj, A.; Smith, K. W.; Ribi, M. 2003. The status and recent breeding performance of the critically endangered Northern Bald Ibis Geronticus eremita population on the Atlantic coast of Morocco. Ibis 145: 419-431.

Jordano, P.; Márquez, M. 2013. Status of the Northern Bald Ibis in southern Spain. HBW Alive Ornithological Note 6. In: Handbook of the Birds of the World Alive. Lynx Edicions, Barcelona. (retrieved from http://www.hbw.com/node/205127 on 13 March 2017).

Latifa, S.; Ouidade, O.; Mohammed, El B. 2016. Morocco wild population update. Pp 29-30 in Boehm C. & Bowden C. G. R. (eds): Northern Bald Ibis Conservation and Reintroduction Workshop. Proceedings of 4th Internatinal Advisory Group for the Northern Bald Ibis (IAGNBI) meeting. Seekirchen, Austria; August 2016.

Matheu, E., del Hoyo, J., Kirwan, G.M. and Garcia, E.F.J. 2014. Northern Bald Ibis (Geronticus eremita). In: del Hoyo, J., Elliott, A., Sargatal, J., Christie, D.A. and de Juana, E. (eds), Handbook of the Birds of the World Alive, Lynx Edicions, Barcelona.

Muñoz, A.-R.; Ramírez, J. 2017. Reintroduced Northern Bald Ibises from Spain reach Morocco. Oryx 51(2): 204-205.

Oubrou, W. and El Bekkay, M. 2013. Rapport sur la reproduction 2013 de la population des Ibis chauves dans la région de Souss-Massa. Report of the 2013 Northern Bald Ibis breeding season at Sous-Massa NP, Morocco. Available at: http://northernbaldibis.blogspot.co.uk/. (Accessed: 07/10/2013).

Oubrou, W. and El Bekkay, M. 2014. Rapport sur la reproduction de l’Ibis chauve dans la région de Souss-Massa. Haut Commissariat aux Eaux et Forêts et à la Lutte Contre la Désertification, Aires Protégées du Maroc, Parc National de Souss Massa.

Oubrou, W. and El Bekkay, M. 2015. Rapport sur la saison de reproduction de l’Ibis chauve Geronticus eremita dans la région Massa. Haut Commissariat aux Eaux et Forêts et à la Lutte Contre la Désertification, Aires Protégées du Maroc, Parc National de Souss Massa.

Serra, G. 2015. The Northern Bald Ibis is extinct in the Middle East – but we can’t blame it on IS. The Ecologist. Available at: http://www.theecologist.org/News/news_analysis/2887380/the_northern_bald_ibis_is_extinct_in_the_middle_east_but_we_cant_blame_it_on_is.html. (Accessed: 29/07/2015).

Serra, G.; Abdallah, M.; Assaed, A.; Abdallah, A.; Al Qiam, G.; Fayad, T.; Williamson, D. 2004. Discovery of a relict breeding colony of Northern Bald Ibis Geronticus eremita in Syria. Oryx 38: 106-108.

Touti, J.; Oumellouk, F.; Bowden, C. G. R.; Kirkwood, J. K.; Smith, K. W. 1999. Mortality incident in Northern Bald Ibis Geronticus eremita in Morocco in May 1996. Oryx 33: 160-167.

UvA Bird Tracking System. Undated. Northern Bald Ibis (Geronticus eremita) Reintroduction programme in Andalusia. http://www.uva-bits.nl/project/northern-bald-ibis-geronticus-eremita-reintroduction-programme-in-andalusia/ (Accessed 13/03/2017).

Wald, C. 2014. Flying lessons. BBC Wildlife August: 82-88.

Waldrappteam. 2014a. Breeding area Burghausen. Waldrappteam. Available at: http://waldrapp.eu/index.php/en/project-sites/breeding-area-burghausen. (Accessed: 29/07/2015).

Waldrappteam. 2014b. Reason for Hope. Waldrappteam Available at: http://waldrapp.eu/index.php/en/project/project-info. (Accessed: 30/07/2015).

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17 Responses to Archived 2018 topic: Northern Bald Ibis (Geronticus eremita): downlist from Critically Endangered to Endangered?

  1. Jorge F. Orueta says:

    I’ve been involved in NBI conservation in Morocco since 2000, and have monitored the evolution of the population since then. I’m currently member of the AEWA working group for the species.
    It’s still soon to download NBI because:
    – The Spanish colony is not still self-sustainable. In fact, this year breeding has totally failed due to predation.
    – In fact, every year some 25 young birds are still released in Andalusia.
    – The cross of several individuals from Spain to Morocco shouldn’t be regarded as an expansion but more a leak of recently released young birds.
    – The Moroccan population, although steadily growing since the 1990s, still needs to expand to other territories to be considered safe. 1996’s mortality (and the lack of evidence of the cause) is a proof of the potential threats that could still impact the species.

  2. I am the manager of the European LIFE+ reintroduction project (www.waldrapp.eu). I basically agree with Jorge F. Orueta in the opinion that it is too soon to downlist the NBI.
    I think, there are promising attempts to reintroduce NBI populations in southern Spain (Projecto Eremita) and in central Europe (our LIFE+ project) and I agree that these European projects are essential to reach the goals of the AEWA Single Species Action Plan.
    But to date, none of both populations reached the minimum viable population size, due to that they are not regarded as self-sustaining. In our project, we aim to reach the MVPs about mid of the 2020’s; I assume our colleague in Spain will reach this threshold some years earlier.
    Thus, I think the global situation for the NBI did change in a positive way, but the Red List status should be modified if we can be fairly sure that this change is sustainable in the sense of the MVBs concept.
    In addition, as written on the IAGNBI website there is a crisis in wardening of the Moroccan NBIs (http://www.iagnbi.org/), this also does not speak – for strategic reasons – for immediate downlisting of the species.
    I also want to point out, that in may view continued management of a release populations may not be a suitable parameter to exclude this population from the assessment of downlisting. As stated in the IUCN reintroduction guidelines, some translocation populations may require long term or even permanent management. Sustainability seems me a more reasonable parameter.
    Finally, I may add that more recent literature for our project is available, either the IAGNBI report 2016 (http://www.iagnbi.org/images/IAGNBI/pdfs/Seekirchen%202016%20report.pdf) or a recently published article in the International Zoo Yearbook (http://onlinelibrary.wiley.com/journal/10.1111/(ISSN)1748-1090/earlyview).

  3. Andy Symes (BirdLife) says:

    Miguel Quevedo (Proyecto Eremita) has provided the following comment:

    It is stunning to hear that BirdLife Redlist team proposes to downlist NBI from CE to Endangered. In the last years significant progress in the Moroccan population has occurred with slightly increase in breeding pairs, but still is the only real population in the world. From our point of view, the arguments presented in the proposal are not good enough to downlist the status. At present the eastern population is extinct in the wild, the Moroccan subpopulation with 116 breeding pairs might still suffer from any catastrophic incident (similar to 1996 event) which could decrease the number of birds.
    Regarding the two introduced populations in Europe, our Austrian colleagues can give us more accurate data on the status and progress of the project, but we feel that could be still soon to consider this migratory population stable and could need some management over time. The Spanish population is considered stable and sedentary but still not sel-sustainable. The number of free-flying birds is considered around 90, with 20 breeding pairs. This population still depends on annual release of zoo-born juveniles (EEP programe). Although positive breeding progress has occurred in the last years, 2017 breeding season has suffered from a severe predation incident in nests (Barca de Vejer) that killed at least 14 chicks and several adults. The culprit of this predation incident is thought to be a pair of eagle owl nesting nearby. This mean that this breeding season has failed with only 2 fledglings hatched in the second breeding site (Torre de Castilnovo, Conil).
    Hence, taking into account all this data we think the NBI population is still in critical endangered status and further assessment, monitoring and conservation measures has to be taken to guarantee their survival.
    Best regrads

    Proyecto Eremita (José Manuel López, Iñigo Sánchez, Miguel A. Quevedo) Spain

  4. I join this debate in my capacity as a member of IAGNBI. I agree with the consensus of comments so far: it would be premature to downlist this species. The designation of a species on the list, however, should be a relatively objective process and not subject to personal opinion. If objective criteria are used, the global population size of wild birds is hardly different to when the species was initially listed as CE, when compared to its historical population size. While there has been an increase in the Moroccan population in recent years, this is still very small and geographically limited. The Spanish birds do not yet form a self-sustaining population, being reliant on annual restocking. The European and Turkish birds are not included in the assessment for the reasons given and Middle-East population probably has been pretty much extirpated over recent years. I don’t see any evidence for downlisting, but if there is, please can it be made clear?

  5. Personally, I think it would be hasty to down list the NBI from (CR) to (EN) because of the lack of information on different ecological and trend aspects using reliable predictors and modelling.

    In fact and despite the regular monitoring of the NBI is Souss Massa national Park and Tamri and the breeding reports published each year. So far there are no current and well-founded scientific studies using accurate statistical models to highlight the trend of Moroccan population over the last 20 years and its interaction with habitats, climate and human parameters.

    My question on which basis we would make such suggestion as increase of the population show a very slow pace over two decades and threats are increasing especially in foraging areas?

    In conclusion there isn’t enough evidence to downlist the species. Yet, the icrease of foraging habitat loss require caution on our part.

  6. Chris Bowden says:

    Its been very instructive to read the comments so far, and personally, I’m also left feeling that downlisting is premature. But we will need to examine the RDB criteria very closely to justify this and these don’t seem as clear cut in this case as for most species. The points that seem to me to be most pertinent are as follows:

    1) I agree and accept the comments that the release projects (including Spain which appears closer to being self-sustaining) can not be considered in any way sustainable as things stand, so this consideration should be disregarded with respect to downlisting the RDB status. (at least until that changes).
    2) We have meanwhile recently witnessed the effective extinction of the relict Eastern breeding population (Syria), with hunting pressure (and other threats) in this context probably still not addressed as key threats for any prospect of return at least in the immediate future.
    3) This means we focus on Morocco and the population size, threats and trend there, which: 3.1) has increased (from 59 to 118 breeding pairs over 19 years) ie marginally increasing almost every year, and
    3.2) World population persists at just two colonies 100km apart, with no expansion in range at all (and growing development threats in the area in fact) – so with the small spatial area covered by those colonies, we could still regard their range as miniscule? This seems to be the strongest (maybe only?) argument for keeping it as CR? So it depends on how you define the area they occur in (obviously the feeding areas over the course of the year are huge by comparison), but at one level, this could be regarded as the physical space of these colonies (ie one cliff-face with 50% of the population and three cliff-faces within 4km of each other holding the other 50%) and so can be regarded as just a few hundred square meters in total?
    3.3) The small area and geographical range of the two colonies mentioned above is especially significant when considering the potential threats to the species, and how susceptible they can be to a single event, threat or problem. Even more worrying is that after the breeding season each year, up to 80% of the world population roosts for several weeks at a single cliff site. Plus the fact that the Tamri area (holding 50% of breeding population) still carries only very rudimentary (basic) protection status.

    With the above points in mind, I agree with the suggestion to await the colonization or recolonisation of an additional site away from Souss-Mass as a quite feasible target to trigger downlisting – which is highlighted as a priority in the updated action plan…

    http://www.unep-aewa.org/en/publication/international-single-species-action-plan-conservation-northern-bald-ibis-ts-no-55

    This seems most logical to me (to use colonization of a third site as a trigger for downlisting) – but lets see what the RDB experts say on applying the criteria consistently across species. Chris

  7. I had posted my comment weeks ago but somehow it was not recorded. Reposting now.

    The proposed down listing of NBI is definitely premature, according to me.
    I agree with the observations of Andrew Cunningham (increase of Morocco colonies is still very small and geographically limited) and of Chris B. (limited geographic range of Morocco colonies).

    The justification by birdlife for downscaling the conservation status of NBI does not include any consideration in relation to the existence of two subpopulations physically separated for centuries and genetically distinct (Pegoraro et al. 2001, Broderick et al. 2001). The use of criteria based only on number of mature individuals does not account for the complexity of having two genetically different subpopulations.

    In these regards, criteria C for CR may be met by NBI: “Population size estimated to number fewer than 250 mature individuals” in combination with point #1:“An estimated continuing decline of at least 25% within three years or one generation, whichever is longer, (up to a maximum of 100 years in the future).

    Provided that the genetic pool (and the cultural/behavioural heritage) of the species is considered (instead of the mature individuals), point #1 may be considered as met because 50% (i.e. the whole eastern subpopulation) will go extinct for good most likely “within three years”.

    Also point #2 of same criteria may be met: “A continuing decline, observed, projected, or inferred, in numbers of mature individuals” (as the species is still declining and actually becoming extinct in its eastern component/ 50% of its genetic pool) in combination with “(ii) at least 90% of mature individuals in one subpopulation.”

  8. Andy Symes (BirdLife) says:

    Thanks to all who have commented on the proposed reassessment of Northern Bald Ibis. Recognising the strength of concern over the proposed downlisting of the species, we have agreed to pend the reassessment until the 2018 Red List update, while keeping the discussion open for further comments. In particular, we are aware that the AEWA Northern Bald Ibis Working Group meeting scheduled to take place in Morocco in September 2017 provides an opportunity to better explain the rationale for the reassessment and to address concerns around the likely status change.

    Whilst recognising that birds from the Spanish reintroduction are seemingly not yet eligible to be included in the Red List assessment, we would like to emphasise that all available evidence clearly shows that the species no longer meets any criteria for listing as Critically Endangered on the global Red List. Regardless of conservation interest in the species, we have to ensure consistency in our assessments and indeed risk these assessments being rejected by IUCN if we fail to do so.

  9. James Westrip (BirdLife) says:

    In 2017, two new colonies of Northern Bald Ibis were discovered in Morocco (see http://medcraveonline.com/IJAWB/IJAWB-02-00021.php?platform=hootsuite, and https://www.birdlife.org/worldwide/news/important-new-breeding-sites-mythical-ibis-discovered). This new evidence defuses the suggestion posed by Chris Bowden in his comment of 15 July 2017, point 3.2, where it was suggested that the very limited range could be a key argument for maintaining a listing as Critically Endangered.

    In an attempt to directly answer some of the other concerns and queries about the proposed downlisting, in September 2017 there was further engagement with species experts via a presentation at the 2nd Meeting of the AEWA Northern Bald Ibis International Working Group. The presentation outlined the IUCN Red List Criteria and explained the outcome of applying these criteria to the current data on Northern Bald Ibis, giving a clear Red List assessment for the species. That presentation has been attached to the bottom of this topic for reference.
    At the end of the presentation, BirdLife’s Red List team (via Skype in Cambridge) answered a number of questions raised by the species experts in Morocco. Below, we recount here a summary of the session, including the questions and responses provided by the team in Cambridge [with some additional notes now incorporated].

    Q 1. How do the IUCN Red List Criteria take into account the social structure of some species’ populations, like Northern Bald Ibis, where the majority of the population congregates in one or a few places at certain times of year (breeding cliffs, post-breeding congregation), and is therefore at much higher risk of being affected by threats than more dispersed species?

    Answer: The population unit for Red List assessments is mature individuals, rather than e.g. number of colonies or post-breeding flocks. However, the Red List Criteria do take account of such phenomena, under Criterion D, whereby species with a restricted area of occupancy (typically <20 sq km) or number of locations (typically ≤5) with a plausible future threat that could rapidly drive the species to Critically Endangered or Extinct, can be listed as Vulnerable under Criterion D2. In this case, however, we’re proposing that the species qualifies at the higher level of Endangered under Criterion D1 anyway (<250 mature individuals).

    Q 2. How do you factor in the degradation of habitat (including the future threat from this), even though the species is increasing now?

    Answer: This was taken into account under the section on Criterion B. Deterioration in quality can be looked at in the present, but the species would not meet the other sub-criteria for listing as Critically Endangered under Criterion B, even if its Extent of Occurrence and Area of Occupancy did meet the respective thresholds. This is because at least one further sub-criteria is required to warrant listing under Criterion B. As there are no extreme fluctuations, the species is found in at least two locations [suspected to be greater than this, with the discovery of the new Moroccan breeding sites], and the species is not severely fragmented, then it does not meet the other sub-criteria and so it does not warrant listing as Critically Endangered under Criterion B.
    Also looking at Criterion C – regarding the future threat of habitat degradation, this does depend on the data uncertainty fields that IUCN provide. For a future decline, we can only either ‘project’ or ‘suspect’ it – the full definitions of these terms can be found in the IUCN guidelines (IUCN Standards and Petitions Subcommittee 2017, available here http://cmsdocs.s3.amazonaws.com/RedListGuidelines.pdf), but for a species to be listed under Criterion C2 based on a future decline, this would have to be ‘projected’ [i.e. based on statistical calculations and justified assumptions], whereas the current situation is more akin to a ‘suspected’ [i.e. based on circumstantial evidence] future continuing decline.

    Q 3. What about the risks to >500 birds concentrated in one site (Souss Massa NP) in winter?

    See answer to Q 1 above

    Q 4. Couldn’t we assess the extinction risk/RL status of the eastern and western populations separately, to draw attention to their very different statuses?

    Answer: BirdLife only assesses the status of the world’s 11,000 birds at species level (and the same is true for virtually every other taxon on the Red List too). However, regional Red List assessments are possible, following IUCN guidelines, and the regional status of the eastern population of NBI has in fact been assessed in that way, for the ‘Arabian Red List’ (https://portals.iucn.org/library/node/46661), where it emerged as CR. This difference will be mentioned and the source cited in the species’s global factsheet when it is updated in 2018.

    Q 5. How can we consider downlisting the species when its historical range has contracted by >90%?

    Answer: Although declines in range (either Area of Occupancy or Extent of Occurrence) are one of the ways in which population reductions may be inferred or suspected under Criterion A, they cannot ‘trump’ direct observation or indices of abundance, where these exist. In the case of NBI, the detailed population monitoring from Morocco clearly shows that the species’s population has increased in recent decades, rather than declined. Furthermore, the timescale relevant to these assessments of extinction risk is limited to 10 years or 3 generations, whichever is longer, which in the case of the NBI means 3 x 8 = c. 24 years (see Q 8 below).

    Q 6. What about the risk of sudden events and catastrophes? For example, under climate change, the increasing frequency of storms is more likely to cause a sudden collapse of one of the nesting cliffs; and the species did undergo a catastrophe just before the 24-year window mentioned above – could the timeframe be extended for key events like this?

    Answer: This is again partly covered by the answer to Q 1 above. The catastrophe mentioned above was a mass die-off of c. 40 individuals in 1996. Whilst this was a terrible occurrence and measures have hopefully been taken to avoid it happening again, if an event took place more than 3 generations ago, it is not technically relevant to the assessment of extinction risk under the IUCN Red List guidelines.
    Also, in short we can’t extend a time frame – we have to stick to the 3 generation period as stipulated by IUCN, so that all Red List assessments are consistent across all taxonomic groups. This is important, otherwise the credibility and reliability of not only BirdLife (as Red List Authority for birds), but also of the whole Red List process could be called into question.
    [Please note that as the event took place in 1996 it did fall within our 3 generation limit. However, this would still not qualify the species for Critically Endangered: a) because over the 3 generation time period (1994-2018) the population has increased (so doesn’t trigger Criterion A); and b) because this event was a one-off Reduction rather than a Continuing Decline, and so it would not meet the conditions for Criterion C.]

    Q 7. If a catastrophe did happen, would BirdLife/IUCN be able to immediately uplist the species to CR again, or would it have to wait e.g. 5 years first?

    The Red List guidelines are very clear on this. Whilst downlisting a species involves waiting 5 years, to ensure that the species’s status really has improved, there is no need to wait before uplisting it to a higher category if something dramatic happens. This should happen without delay, and the fact that BirdLife updates the global Red List for birds annually means that such emergency uplists can happen swiftly. We can also add a caveat to the Red List rationale if/when we downlist this species to Endangered in 2018, acknowledging that any such catastrophe may lead to it being uplisted to Critically Endangered in future.

    Q 8. What is the basis of the generation length (8 years)? It sounds quite short for a species that can live much longer than that. Do you have an account of the method, and then how it was applied specifically to this species?

    The IUCN Red List Guidelines defines generation length as the average age of parents of the current cohort (i.e. newborn individuals in the population). Details of the various ways in which the value of a species’s generation length can be calculated are presented in the Guidelines (http://cmsdocs.s3.amazonaws.com/RedListGuidelines.pdf). For Northern Bald Ibis, the value currently used in the Red List assessment (8 years) is the same as that which has been used in the species’s assessments for >20 years. This was calculated using a published estimate of mean age at first breeding and extrapolated maximum longevity in the wild.
    Even if we used a higher value, this would not affect the proposal for a status change. For example, using 10 years would give us a three generation period of 30 years, i.e. 1988-2018. Since there is no continuing decline, the only relevant criterion is A. The wild global population would need to have still been of the order of 1,200 mature individuals in 1988 to equate to an overall decline of >80% over this period, and there is no evidence that there were anywhere near this number left at that point. Therefore, even using a generation length estimate of 10 years, it would still not qualify as CR.

  10. Raffael Ayé says:

    There are strict criteria (A to E) for the RL assessment. Reading these, it seems clear that none of the criteria for CR are met. However, probably several criteria for EN are met.
    Thus the species must be classified as EN.
    Then it is very important, how this will be communicated. I hope that all the people involved in the conservation of the species in Morocco will celebrate. This is really the achievement of their work. As far as I have understood, this work was carried forward with a rather tight budget over several decades. Population growth is slow, but it has been steady. It’s fantastic what our colleagues have achieved in Morocco!!
    At the same time communication needs to be clear: the species has not achieved a favourable conservation status – far from. It is still globally threatened. If developers start building in the feeding grounds of the species in Morocco and if authorities allow this to happen, it may be just a question of a few years, until the species has to be uplisted to CR again…

  11. Jurek Dyczkowski says:

    Speaking as an interested birdwatcher, I written formally concerns of ibis researchers above (congregation on small number of cliffs and roosts, vulnerability to unknowns die-offs ). They indeed fulfil the criteria of Critically Endangered.

    2. Area of occupancy estimated to be less than 10 km2
    AND
    a.: Severely fragmented or known to exist at only a single location.
    b. Continuing decline, observed, inferred or projected, in any of the following:
    (iii) area, extent and/or quality of habitat
    c. Extreme fluctuations in any of the following:
    (iv) number of mature individuals.

    Explanation:
    2. Area of occupancy is defined as the area actually occupied by individuals within a larger area of occurrence. ‘In some cases (e.g. irreplaceable colonial nesting sites, crucial feeding sites for migratory taxa) the area of occupancy is the smallest area essential at any stage to the survival of existing populations of a taxon. ‘
    For NBI, breeding cliffs and post-breeding roost cliffs and probably drinking places as well qualify as an area of occupancy. Combined area of each is much below 10km2. It is correct to define the area of occupancy narrowly, because the birds are indeed regularly physically present only there. A negative confined to the small place (e.g. predatory attack, takeover of competing cormorants, or human disturbance on a breeding cliff, application of a poison of a drinking place) certainly can affect large part of population.

  12. Jurek Dyczkowski says:

    (CONTINUED)
    a.: Severely fragmented or known to exist at only a single location.:
    “The term ‘location’ defines a geographically or ecologically distinct area in which a single threatening event can rapidly affect all individuals of the taxon present. The size of the location depends on the area covered by the threatening event and may include part of one or many sub-populations. Where a taxon is affected by more than one threatening event, location should be defined by considering the most serious plausible threat. “
    It is most appropriate to consider all breeding and roosting cliffs as a single location, because NBIs regularly exchange individuals with far more than one individual per generation. An outbreak of disease or poison can affect all NBIs in Morocco, both north and south of Tamri.
    If the opposite view is taken that every breeding cliff is a different sub-population (in my opinion not appropriate) then the population is severely fragmented.
    b(iii): Foraging habitat certainly is declining in quality.
    c(iv): Extreme fluctuations in the number of mature individuals. IUCN criteria do not specify minimum size range nor time frame of these fluctuations. This is contrary to the assertion that the fluctuation must take place within 3 last generations to count.

  13. Jurek Dyczkowski says:

    (CONTINUED)
    Death if 20% of breeding individuals within few weeks in 1996, for a slow breeding bird can be considered extreme. The event took place within 3 generations ago, its reasons are unknown and therefore have not been eliminated. All researchers agree that a similar mortality event can realistically happen today. My understanding is that the most likely cause of the 1996 mortality was either a virus or poisoning, and both are as likely today.

    It is probable that the introduced NBI population in Spain will become sustainable in several years in future. The NBI will then still fulfil the criteria of Critically Endangered. This is based on a very small area of occupancy (concentration on a few breeding and roost sites), severe fragmentation of these sites, and extreme population fluctuation. Here the fluctuation is death of almost all young and several adults in Spain in 2017, due to a single individual predator (probably eagle owl).

    I wish all the best success in the Northern Bald Ibis conservation,

  14. Jurek Dyczkowski says:

    I understand there is also some confusion due to:
    -Not presenting quantifable data how agriculture intensified in the Tamri region, which would project on foraging habitat quality.
    -Not accounting that NBIs exchange between breeding cliffs and concentrate further in non- breeding season, making a single ‘locality’ or ‘subpopulation’.
    -Not accounting the highly fragmented and local nature of suitable breeding and roost sites (due to geology).

  15. James Westrip (BirdLife) says:

    Speaking as an interested birdwatcher, I written formally concerns of ibis researchers above (congregation on small number of cliffs and roosts, vulnerability to unknowns die-offs ). They indeed fulfil the criteria of Critically Endangered.
    2. Area of occupancy estimated to be less than 10 km2
    AND
    a.: Severely fragmented or known to exist at only a single location.
    b. Continuing decline, observed, inferred or projected, in any of the following:
    (iii) area, extent and/or quality of habitat
    c. Extreme fluctuations in any of the following:
    (iv) number of mature individuals.
    Explanation:
    2. Area of occupancy is defined as the area actually occupied by individuals within a larger area of occurrence. ‘In some cases (e.g. irreplaceable colonial nesting sites, crucial feeding sites for migratory taxa) the area of occupancy is the smallest area essential at any stage to the survival of existing populations of a taxon. ‘
    For NBI, breeding cliffs and post-breeding roost cliffs and probably drinking places as well qualify as an area of occupancy. Combined area of each is much below 10km2. It is correct to define the area of occupancy narrowly, because the birds are indeed regularly physically present only there. A negative confined to the small place (e.g. predatory attack, takeover of competing cormorants, or human disturbance on a breeding cliff, application of a poison of a drinking place) certainly can affect large part of population.

    Response:
    We accept that the Area of Occupancy (AOO) is likely to be extremely small as described above, but referring to the IUCN criteria, we cannot simply use the actual area of certain occupied localities to calculate an AOO. IUCN specifies a procedure using 2km x 2km grids to calculate the AOO. The current value, based on the breeding areas (the period of the year when the birds are most concentrated) as suggested, has been precautionarily taken as 10km2. This now needs to be re-calculated (following IUCN guidelines) because of the discovery of the new breeding cliffs, which means it is even less likely that the AOO value would be <10km2. However, even if the revised AOO was calculated as <10km2, the species would still not warrant listing as Critically Endangered under criterion B2, because the information available shows that the other requisite conditions are not met (see below).

    a.: Severely fragmented or known to exist at only a single location.:
    “The term ‘location’ defines a geographically or ecologically distinct area in which a single threatening event can rapidly affect all individuals of the taxon present. The size of the location depends on the area covered by the threatening event and may include part of one or many sub-populations. Where a taxon is affected by more than one threatening event, location should be defined by considering the most serious plausible threat. “
    It is most appropriate to consider all breeding and roosting cliffs as a single location, because NBIs regularly exchange individuals with far more than one individual per generation. An outbreak of disease or poison can affect all NBIs in Morocco, both north and south of Tamri.

    Response:
    As specified in the IUCN guidelines, location must be defined according to the most serious plausible threat. Poisoning or disease could have an impact on the species, but we have to stress that, at the moment (and we all hope this remains the case – vigilance is important here), there has been no indication of further issues since 1996. Based on the IUCN threat scoring system, hunting is currently listed as the most serious threat to this species – but this applies primarily to the eastern population, and so is probably outdated and needs a revision. The next most serious threats mentioned are the intensification of agriculture and the impacts of problematic species (reducing breeding success).
    Given the distance between some of the breeding sites in Morocco, these threats are very unlikely to impact all of the individuals in the population, as the species is not found at one location. We are not saying that the potential for future impacts of disease or poisoning are not a worry – just that they are not the most serious plausible threat to the species at the moment.
    There is a short period (2-4 weeks) most years when up to 80% of the population roost together at a single site, and this is perhaps the main concern in this respect (and when vigilance is paramount). But following IUCN, this would still mean that the species is not found at one location as defined under sub-criterion B2a.

    If the opposite view is taken that every breeding cliff is a different sub-population (in my opinion not appropriate) then the population is severely fragmented.

    Response:
    This is not the case. By IUCN guidelines, to be severely fragmented, >50% of the population must be in isolated patches smaller than that required to support a viable population AND separated by a large distance [sufficiently large that they are outside of the normal dispersal distance]. This is obviously not the case for Northern Bald Ibis, and so it cannot be regarded as severely fragmented under sub-criterion B2a.

    b(iii): Foraging habitat certainly is declining in quality.

    Response:
    This seems likely, but it needs very detailed studies to clarify the speed and extent. Without such evidence, it is difficult to justify invoking its use under sub-criterion B2b(iii), particularly when none of the other attributes covered by B2b are declining (and some are increasing).

    c(iv): Extreme fluctuations in the number of mature individuals. IUCN criteria do not specify minimum size range nor time frame of these fluctuations. This is contrary to the assertion that the fluctuation must take place within 3 last generations to count.
    Death if 20% of breeding individuals within few weeks in 1996, for a slow breeding bird can be considered extreme. The event took place within 3 generations ago, its reasons are unknown and therefore have not been eliminated. All researchers agree that a similar mortality event can realistically happen today. My understanding is that the most likely cause of the 1996 mortality was either a virus or poisoning, and both are as likely today.

    Response:
    The 1996 mortality was a very worrying single event, but it cannot be regarded as a fluctuation. A fluctuation normally reflects a natural cycle of increases and decreases, and this has not been the case over the past 20 years, with an otherwise relatively stable sustained increase. Additionally, IUCN specifies a size range for fluctuations. The guidelines state they may be considered extreme if they are of an order of magnitude (i.e. a tenfold) increase or decrease. The single 1996 decrease example of 20% therefore certainly doesn’t qualify as part of a natural fluctuation cycle, and as such, this cannot be used to invoke sub-criterion B2c(iv).

    It is probable that the introduced NBI population in Spain will become sustainable in several years in future. The NBI will then still fulfil the criteria of Critically Endangered. This is based on a very small area of occupancy (concentration on a few breeding and roost sites), severe fragmentation of these sites, and extreme population fluctuation. Here the fluctuation is death of almost all young and several adults in Spain in 2017, due to a single individual predator (probably eagle owl).

    Response:
    As earlier stated, the Spanish population is not (yet at least) considered as part of the discussion here, as it is acknowledged by all that it is not self-sustaining. As the evidence already provided (and summarised again above) shows that the species does not meet the requirements for listing as CR under criterion B, the inclusion of the Spanish population in an assessment would have no impact on its listing under that criterion.

    I wish all the best success in the Northern Bald Ibis conservation,
    I understand there is also some confusion due to:
    -Not presenting quantifable data how agriculture intensified in the Tamri region, which would project on foraging habitat quality.
    -Not accounting that NBIs exchange between breeding cliffs and concentrate further in non- breeding season, making a single ‘locality’ or ‘subpopulation’.
    -Not accounting the highly fragmented and local nature of suitable breeding and roost sites (due to geology).

    Response:
    We have taken this information into account when conducting our Red List assessment, and have been in direct contact with many experts on the Northern Bald Ibis to make sure we have the best possible knowledge about the species’ ecology before conducting our assessment. As clarified above, we recognise that there is likely a decline in the quality of foraging habitat – whether that has been quantified or not.
    To summarise, following the IUCN criteria and guidelines: the species is not found at only one location; its distribution is not severely fragmented; and it is not undergoing extreme fluctuations. This means that the species does not meet the conditions for listing as CR under criterion B (whether the revised AOO is found to be <10km2 or not).
    Great credit should be given to the efforts within Morocco by the National Park and the conservation programmes there that the population trend has been sustained and positive for 20 years now. This should be highly celebrated. But the conclusions (as put forward in the PowerPoint Presentation attached to the topic above) still stand, and by observing the IUCN criteria for this species, we remain clear that downlisting to EN is appropriate.

  16. James Westrip (BirdLife) says:

    Preliminary proposals

    Based on available information, our preliminary proposal for the 2018 Red List would be to adopt the proposed classifications outlined in the initial forum discussion.

    There is now a period for further comments until the final deadline 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.

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