Archived 2010-2011 topics: Pale-headed Brush-finch (Atlapetes pallidiceps): downlist to Endangered?

Link to BirdLife species factsheet for Pale-headed Brush-finch

Pale-headed Brush-finch Atlapetes pallidiceps is currently listed as Critically Endangered under criteria B1a+b(i,ii,iii); B2a+b(i,ii,iii), on the basis that it occupies an extremely small range, and was regarded as threatened by habitat loss and, because of its rarity, brood parasitism by Shiny Cowbirds Molothrus bonariensis.

Thanks to the success of intensive conservation efforts, including land protection, habitat management and control of M. bonariensis (Sornoza Molina 2000, Schmidt and Schaefer 2003, M. Juiña in litt. 2008), the species has very probably been saved from extinction, and it has been increasing, possibly since 1999. In 1999, the number of occupied territories was estimated at 12-22 (N. Krabbe in litt. 2007); this has since increased to an estimated 110-120 occupied territories in 2008 (M. Juiña in litt. 2008), with 113 occupied territories recorded in 2009 (D. Wege in litt. 2009).

The species is believed to have reached saturation point in the available habitat (D. Wege in litt. 2009), and further habitat creation is constrained by high land prices, whilst difficulty in controlling the impact of M. bonariensis will also limit further population growth. Despite these difficulties, there are plans for further land purchases and the establishment of another reserve (N. Krabbe in litt. 2007).

Although the species’s range size meets the thresholds for Critically Endangered under the B criterion, it is stable and will probably increase with continued conservation work, along with the population, which has shown an extremely rapid increase over the last 11 years (three generations); thus the species does not qualify as threatened under the B criterion. It is therefore eligible for downlisting to Endangered under criterion D1, on the basis that it has a population of fewer than 250 mature individuals. Comments are invited on this proposed category change.

Schmidt, V. and Schaefer, H. M. (2003) Pale-headed Brushfinch recovery project in southwestern Ecuador 2002-2003. Final Report.

Sornoza Molina, F. (2000) Fundación Jocotoco: conservation action in Ecuador. World Birdwatch 22: 14-17.

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12 Responses to Archived 2010-2011 topics: Pale-headed Brush-finch (Atlapetes pallidiceps): downlist to Endangered?

  1. Niels Krabbe says:

    Should be updated with
    Krabbe, N., Juiña, M. and Sornoza, A.F. 2010.
    Marked population increase in Pale-headed Brush-finch
    Atlapetes pallidiceps in response to cowbird control.
    J.Orn. Published Online 17 Aug 2010
    DOI 10.1007/s10336-010-0567-z

  2. I have discussed this issue with Fundacion Jocotoco, the species guardian. In my opinion and theirs, down-listing is premature. While it could be argued that downlisting is justified according to the B criterion because the species is not declining anymore, it is still only known from a single site. There is no other viable (self-sustaining) population known and it is indeed unlikely to exist given the pressures of cowbirds in the species’ range. The recent fire in 2010 (as well as previous fires e.g., in 2003) in parts of the reserve have highlighted the continuing vulnerability of that species in case of a larger fire. The species still meets B1 (a) and B2 (a) criteria. Interestingly, owing to the strong emphasis on population declines by IUCN criteria (obviously justified9 it does not even qualify as endangered. Thus a present down-listing would not improve the fit with the IUCN criteria.
    Fundacion Jocotoco is planning to establish a second reserve. If that holds a second population of approx. 50 individuals, I think down-listing would be better justified.
    Best
    Martin

  3. Juan Freile says:

    Given the tiny global range, small population, and continuous threats, it might not be downlisted.
    The fact that its populations have increased does not justify downlisting, though it reflects some successful management practices by Jocotoco colleagues. As Martin suggests, large fires can entirely destroy the tiny reserve wherein it is confined, despite increases in population size.
    Land tenure in the area is complex, not easy (and definitely not inexpensive) to expand current protected areas. Also, habitat is severely degraded and fragmented, seemingly constraining further increases in population.
    Being conservative, I suggest keeping CR category for the species. 113 pairs is not a big figure…

  4. Andy Symes says:

    Please note that, contrary to Martin Schaefer’s comment, the species does indeed qualify as Endangered (under criterion D1 – fewer than 250 mature individuals).

    The Red List is a measure of extinction risk rather than conservation priority, and it is clear that as this species has probably been increasing since 1999 its extinction risk, although still undoubtedly high, has decreased. The brush-finch will remain the highest priority for conservation (and indeed the Rio Jubones site will still qualify as an Alliance for Zero Extinction site) even if it is reclassified as Endangered – there is no reason to suggest its reclassification as EN would or should affect the excellent ongoing conservation work for this species.

    It is imperative that BirdLife apply the Red List criteria objectively and consistently – and as a conservation NGO that is also a Red List authority we are at particular risk from criticism in this regard.

    Other species with tiny ranges and very small populations which are Endangered under D1 include Rodrigues Warbler, Black Robin, Rarotonga Monarch and Lord Howe Woodhen. Species with tiny ranges and tiny populations which are continuing to decline, such as Dusky Starfrontlet, Stresemann’s Bristlefront and Cebu Flowerpecker, are at higher risk of extinction and rightly remain Critically Endangered. If the status of the Pale-headed Brush-finch suffers a downturn in the future and there is evidence for a population decline, or good reason to suspect that one will occur in the near future, it will of course again be eligible for uplisting to CR.

    BirdLife International

  5. Niels Krabbe says:

    Again: I am not sure fire is a threat. It rather improves the habitat. The main threat is cowbird parasitism. Cowbird control is a difficult task. The continued presence of a controller as skilled as the present one is hard to guarantee. I therefore think the species should keep its status as critically endangered.

  6. Andy Symes says:

    This would be a good example of a species we would apply a Conservation Dependent tag – we’re working on developing this.

    According to the Red List guidelines:
    “The criteria for the threatened categories are to be applied to a taxon whatever the level of conservation action affecting it”.

  7. Juan Freile says:

    Considerando que los criterios de UICN miden probabilidad de extinción en un plazo determinado, no la situación en tiempo presente, esta discusión no se trata sobre prioridad de conservación sino sobre su estatus real en corto, mediano o largo plazo. Si bien la población ha crecido bastante, lo cual nos alegra a todos, su probabilidad de extinción sigue siendo igual de grande. Me parece que la experiencia de Niels Krabbe con la especie, que le lleva a recomendar que se la mantenga en CR (último comentario), deberían tomarse con más atención que el esperanzador aumento poblacional. Vale mantener un principio de precaución. ¿Qué tal si por algún motivo no se puede continuar con el control poblacional de Molothrus? ¿Qué tal si el hábitat, por razones de difícil control, se altera, modifica, pierde, etc? ¿Qué tal si la fundación que maneja la reserva no puede continuar protegiendo la tierra? Me parece una ligereza pensar en bajar de categoría porque la población ha aumentado, ya que todos los individuos están prácticamente empaquetados en una sola localidad. Ese es un argumento por sí solo para mantenerla en CR.

  8. Respect to the status of Pale-headed Brush-finch, downlist the species is hurried. As explained in the proposal the species accomplish with at list one of the criteria (A to E). Because of their restricted distribution it accomplish the criterio B. I coincide with Martin which indicate that currently although conservation plans include to establish new populations, they have not been established yet. It remains to be tested also if this likely new population becomes succesful. considering this, Pale-headed Brush-Finch accomplish with the A3 criteria which indicate a reduction of the population suspected to be ≥ 80 (nowadays, there is only one population which is threated by cowbird parasitism). Furthermore, population projection (only 113 pairs) which not indicate a decline, they don’t indicate an increasing healthy population. In fact, they indicate that a crowded population is expected.

    • Andy Symes says:

      To further clarify points raised by a couple of correspondents – no, the species does not meet criterion B as it is not undergoing a continuing decline in any of i) extent of occurrence; ii) area of occupancy; iii) area, extent and/or quality of habitat; iv) number of locations or subpopulations; v) number of mature individuals, nor is it undergoing extreme fluctuations. Small range size and restriction to one location are not sufficient to maintain the species under B – it must also meet at least two of the subcriteria (please see http://www.birdlife.org/datazone/info/spcredcrit for more detail on the Red List criteria).

      A3 does not apply unless there is good reason to suspect that a decline >80% will occur in the future – I am not aware of anything to suggest that this is the case here. Were there to be a change in management of the reserve or in the level or effectiveness of cowbird control, or any novel threat likely to lead to a decrease in the population the species would of course be reassessed and would almost certainly return to CR.

  9. In response to Andy’s comment: Yes, I know, it barely qualifies as endangered under criterion D1 with ~113 singing males (assuming a similar number of females; these have not been counted in recent years. In fact, I think they have last been counted in 2003 by me or 2004 by Mery Juina, Niels correct if I am mistaken). But if the population increases (and this is what you assume) to,say, 12 more singing males, it does not qualify anymore even as endangered!
    I understand the need to apply criteria rigorously (which is what you need to do then also in case of a population increase to >250 individuals), but it is here, where these criteria do simply not match the situation in the field. I think the IUCN criteria –as good as they are– place unduly emphasis on population decline and not strong enough emphasis on population size. Well, we will certainly not change these criteria for the brushfinch, but I do think they may need some adjustment.
    Lastly, we need to employ a new hunter this year. This is exactly the change of the level in effectiveness of cowbird control that you refer to in your new comment.
    I would ask you to postpone the decision on downgrading until the end of the breeding season (end of April), when we will have new data on population size and hopefully some data on evaluating the success of controlling cowbirds in 2011 with new personnel.

  10. Niels Krabbe says:

    Thanks Andy, for clarifying why it must be downgraded according to the present criteria.
    Contrary to earlier reports (Oppel, S., Schaefer, H. M., Schmidt, V., Schröder, B. 2004. How much suitable habitat is left for the last known population of the Pale-headed Brush-Finch? The Condor 106: 429-434, and D. Wege in lit. 2009 (cited in 3rd paragraph in the first posting above)), there is no indication of a saturation yet (see Krabbe et al. 2010), but it will probably occur at ca. 150 pairs, when the population will just exceed the magic 250 adult birds. Will it then have to be further downgraded?
    As you point out, it will need yearly reassessment. If the cowbird controller catches the flu in the peak breeding season, the population could fall considerably (40% of the adult males are replaced every year), so the bird would suddenly become critically threatened again(decrease and below magic limit).

  11. Niels Krabbe says:

    Concerning number of females: I have tried to see both sexes of every pair every year, but in later years the population has been too big. Any male that could be called in repeatedly had a mate, so there is no reason to think that the number of females is smaller than the number of territorial males. If mortality of females is higher (as should perhaps be expected), then more females must be born than males or some males not have territories.

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