Henna-hooded Foliage-gleaner (Clibanornis erythrocephalus): revise global status?

BirdLife species factsheet for Henna-hooded Foliage-gleaner

Henna-hooded Foliage-gleaner (Clibanornis erythrocephalus) occurs in western Ecuador and north-western Peru. The species inhabits the understorey of deciduous and moist evergreen forests and woodlands at elevations of 150-1,350 m along the slopes and outlying ridges of the western Andes (Pople et al. 1997, Ridgely and Greenfield 2001, Miller 2020). It persists in secondary woodland and forest edge, occasionally even narrow woodland strips along watercourses and disturbed scrub near forest (Ridgely and Tudor 1994), but viable populations cannot persist in severely degraded habitats (J. Freile in litt. 2008, Miller et al. 2012).

The most severe threat to Henna-hooded Foliage-gleaner is the loss and degradation of its habitat. In western Ecuador, deforestation rates amounted to 57% per decade between the 1950s and 1980s (Dodson and Gentry 1991). Habitat loss is ongoing at a lower level (Tracewski et al. 2016, Global Forest Watch 2020), as forests are converted for cattle grazing and human encroachment.

Henna-hooded Foliage-gleaner is currently listed as Vulnerable under Criteria A2c+3c+4c; B1ab(i,ii,iii,iv,v); C2a(i) (BirdLife International 2020). However, new information regarding the distribution range and trends in population size and habitat availability suggests that the species may warrant a change in Red List status. Therefore, it will be re-assessed against all criteria:

Criterion A – The population trend has not been estimated directly, but the species is suspected to be in decline due to habitat loss. Forest loss over the past three generations (10.2 years; Bird et al. 2020)* has been low within the range (potentially <2%; Tracewski et al. 2016, Global Forest Watch 2020). The species is known to tolerate moderate levels of habitat degradation, but it is absent from heavily degraded areas (Ridgely and Tudor 1994, J. Freile in litt. 2008). While it can be precautionarily assumed that population declines are greater than forest loss, the rate of population decline is unlikely to exceed 20% over three generations (10.2 years). The species therefore qualifies as Least Concern under Criterion A.

Criterion B – The Extent of Occurrence (EOO) for this species is 56,400 km2. This is too large to warrant listing as threatened under Criterion B1, and Henna-hooded Foliage-gleaner qualifies for Least Concern under this criterion. The Area of Occupancy (AOO) has not been quantified according to IUCN guidelines (IUCN Standards and Petitions Committee 2019), and so the species cannot be assessed against Criterion B2.

Criterion C – The population size of Henna-hooded Foliage-gleaner has been placed in the band 2,500-9,999 mature individuals. This meets the threshold for listing as threatened under Criterion C; however, to do so, further conditions must be met.

The species is suspected to decline due to habitat loss. A suspected decline precludes a listing as threatened under Criterion C, and the species can at most be listed as Near Threatened, provided that further conditions are fulfilled. The species is thought to form two subpopulations, a smaller one in western Ecuador and a larger one in northern Peru/southern Ecuador. The sizes of the subpopulations have not been quantified; however given the total population size it is unlikely that none of them contains more than 1,000 mature individuals. The species does not meet sub-criterion 2a. There is no evidence that the species is undergoing extreme fluctuations, and so sub-criterion 2b is not met either. The rate of decline is thought to be 1-19% over three generations (10.2 years); assuming that the true rate of decline is closer to the higher end of the estimate, this number fulfils sub-criterion 1. Overall, while Henna-hooded Foliage-gleaner does not meet sufficient conditions to warrant listing as threatened, it can be considered Near Threatened, approaching the threshold for listing as threatened under Criterion C1.

Criterion D – The population size and range are too large to warrant listing as threatened under Criterion D. Henna-hooded Foliage-gleaner is therefore assessed as Least Concern under this criterion.

Criterion E – To the best of our knowledge no quantitative analysis of extinction risk has been conducted for this species. Therefore, it cannot be assessed against this criterion.

Therefore, it is suggested that Henna-hooded Foliage-gleaner (Clibanornis erythrocephalus) be listed as Near Threatened, approaching the threshold for listing as threatened under Criterion C1. We welcome any comments on the proposed listing.

Please note that this topic is not designed to be a general discussion about the ecology of the species, rather a discussion of its Red List status. Therefore, please make sure your comments are relevant to the discussion outlined in the topic. By submitting a comment, you confirm that you agree to the Comment Policy.

*Bird generation lengths are estimated using the methodology of Bird et al. (2020), as applied to parameter values updated for use in each IUCN Red List for birds reassessment cycle. Values used for the current assessment are available on request. We encourage people to contact us with additional or improved values for the following parameters; adult survival (true survival accounting for dispersal derived from an apparently stable population); mean age at first breeding; and maximum longevity (i.e. the biological maximum, hence values from captive individuals are acceptable).

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

References

Bird, J. P.; Martin, R.; Akçakaya, H. R.; Gilroy, J.; Burfield, I. J.; Garnett, S.; Symes, A.; Taylor, J.; Šekercioğlu, Ç.; Butchart, S. H. M. 2020. Generation lengths of the world’s birds and their implications for extinction risk. Conservation Biology online first view.

BirdLife International. 2020. Species factsheet: Clibanornis erythrocephalus. http://www.birdlife.org (Accessed 1 April 2020).

Dodson, C. H.; Gentry, A. H. 1991. Biological extinction in western Ecuador. Annals of the Missouri Botanical Garden 78: 273-295.

Global Forest Watch. 2020. Interactive Forest Change Mapping Tool. http://www.globalforestwatch.org (Accessed 1 April 2020).

IUCN Standards and Petitions Committee. 2019. Guidelines for using the IUCN Red List Categories and Criteria. Version 14. http://www.iucnredlist.org/documents/RedListGuidelines.pdf.

Miller, E. T. 2020. Henna-hooded Foliage-gleaner (Clibanornis erythrocephalus), version 1.0. In: Schulenberg, T. S. (ed.). Birds of the World. Cornell Lab of Ornithology, Ithaca, NY, USA. https://doi.org/10.2173/bow.hhfgle1.01 (Accessed 1 April 2020).

Miller, E. T.; Greeney, H. F.; Lichter-Marck, I.; Lichter-Marck, E.; Cabrera F. L. E. 2012. The breeding of the Henna-hooded Foliage-gleaner (Hylocryptus erythrocephalus), with notes on conservation concerns. Ornitología Neotropical 23: 517–527.

Pople, R. G.; Burfield, I. J.; Clay, R. P.; Cope, D. R.; Kennedy, C. P.; López Lanús, B.; Reyes, J.; Warren, B.; Yagual, E. 1997. Bird surveys and conservation status of three sites in western Ecuador: final report of Project Ortalis ’96. CSB Publications, Cambridge, UK.

Ridgely, R. S.; Greenfield, P. J. 2001. The Birds of Ecuador. Vols. 1–2. Cornell University Press & Christopher Helm, Ithaca, NY, USA & London, UK.

Ridgely, R.S.; Tudor, G. 1994. The birds of South America. University of Texas Press, Austin, TX, USA.

Tracewski, Ł.; Butchart, S. H. M.; Di Marco, M.; Ficetola, G. F.; Rondinini, C.; Symes, A.; Wheatley, H.; Beresford, A. E.; Buchanan, G. M. 2016. Toward quantification of the impact of 21st-century deforestation on the extinction risk of terrestrial vertebrates. Conservation Biology 30: 1070-1079.

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5 Responses to Henna-hooded Foliage-gleaner (Clibanornis erythrocephalus): revise global status?

  1. Red List Team (BirdLife International) says:

    Global Forest Change data on tree cover loss up to 2019 have now been released and made available via Global Forest Watch. Based on these data, over three generations (10.2 years) approximately 1.8% of tree cover with 75% canopy cover was lost from within the species’s range (Global Forest Watch 2020). This does not affect the above assessment under Criterion A.

  2. Juan Freile says:

    We have estimated a potential population loss in Ecuador greater than 30%. Besides forest loss by deforestation, the species is affected by habitat loss due to free-ranging cattle (mainly goats) even in areas that keep good forest cover (i.e., including more forested areas in northern Peru). The Peruvian population might be more stable though given that dry forest in N Peru is more extensive and continuous.
    Your calculation of EOO is overestimating the species actual EOO. In our assessment for the Ecuador Red List, we adjusted our first estimation of EOO by removing unsuitable habitat in the intervening area between the northern and southern portions of the species original EOO (following IUCN guidelines). The species EOO is actually absent from the intervening area, as occurs in several other Tumbesian endemics.
    A recalculation of its EOO, coupled with low number of localities and a known decline in habitat quality plus a suspected decline in number of mature individuals, might result in the species being classified as VU under criterion B1a,b(iii,v).

    • Red List Team (BirdLife International) says:

      Thank you very much for your comment. We are afraid but your quantification of the EOO does not follow IUCN guidelines. The guidelines clearly state that the EOO needs to be quantified as a continuous Minimum Convex Polygon, and it is not possible to exclude areas of unsuitable habitat. Please have a look at the IUCN Red List Guidelines (chapter 4.9), as you seem to be mistaking the mapped range for the EOO. Please also check chapter 4.11 for a definition of the concept of ‘location’ and chapter 4.6 for the level of data quality that is required to invoke condition b(v).

  3. Red List Team (BirdLife International) says:

    Many thanks to everyone who has contributed to this discussion. We greatly appreciate the time and effort invested by so many people in commenting. The window for consultation is now closed. We will analyse and interpret the new information and post a preliminary decision on this species’s Red List status on this page in early July.

    Thank you once again,
    BirdLife Red List Team

  4. Red List Team (BirdLife International) says:

    Preliminary proposal

    Based on available information, our preliminary proposal for the 2020 Red List would be to adopt the proposed classification 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 2020 Red List categories will be published on the BirdLife and IUCN websites in December 2020/January 2021, following further checking of information relevant to the assessments by both BirdLife and IUCN.

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