Grey-hooded Sunbird (Aethopyga primigenia): revise global status?

BirdLife species factsheet for Grey-hooded Sunbird

Grey-hooded Sunbird (Aethopyga primigenia) is endemic to Mindanao, Philippines. It occurs in forest and on forest edges at altitudes of 1,000-1,700 m (Mohagan et al. 2015). The species is described as common. Assuming that the species occurs at the same density as a congener, Lovely Sunbird A. shelleyi (49.1 individuals/km2; Santini et al. 2018), Grey-hooded Sunbird might number c. 590,000 individuals, equating to 400,000 mature individuals. Forests within the range of Grey-hooded Sunbird are not thought to be under imminent threat (Collar et al. 1999, Cheke et al. 2001, see also Tracewski et al. 2016, Global Forest Watch 2020) and the species is thought to be stable.

Grey-hooded Sunbird has been considered Near Threatened, approaching the threshold for listing as threatened under Criterion B1ab(iii) (BirdLife International 2020). However, this is no longer tenable because this was based on an Extent of Occurrence (EOO) value calculated as the ‘area of mapped range’. This is no longer appropriate and the EOO should be calculated using a Minimum Convex Polygon (see IUCN 2001, 2012, Joppa et al. 2016), as EOO is a measure of the spatial spread of areas occupied by a species, not the actual area it occupies. The resulting EOO value now exceeds the thresholds required to maintain the species’s current listing, and as such it potentially cannot retain its current Red List status. Therefore, we have fully reviewed the species here against all criteria.

Criterion A – The population is thought to be stable. The only threat know to Grey-hooded Sunbird is habitat loss, but forest loss within the range has been very low (<5% over ten years; Tracewski et al. 2016, Global Forest Watch 2020; one generation length being 2.4 years; Bird et al. 2020*). Therefore, Grey-hooded Sunbird may be listed as Least Concern under Criterion A.

Criterion B – The newly calculated Extent of Occurrence (EOO) for this species is 54,400 km2. This is too large to meet the threshold for Vulnerable under Criterion B1, and Grey-hooded Sunbird may be listed as Least Concern under this criterion. The Area of Occupancy (AOO) has not been quantified following IUCN Guidelines (IUCN Standards and Petitions Committee 2019), and therefore the species cannot be assessed against Criterion B2.

Criterion C – The global population size is too large to warrant listing as threatened under Criterion C. Therefore, Grey-hooded Sunbird may be considered Least Concern under this criterion.

Criterion D – The global population size and range are too large to warrant listing as threatened under Criterion D. Therefore, Grey-hooded Sunbird may be considered Least Concern under this criterion.

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

Therefore, it is suggested that Grey-hooded Sunbird (Aethopyga primigenia) be listed as Least Concern.We welcome any comments to 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 the species’ Red List status. Therefore, please make sure your comments are relevant to the species’ Red List status and the information requested. 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: Aethopyga primigenia. http://www.birdlife.org (Accessed 26 February 2020).

Cheke, R. A.; Mann, C. F.; Allen, R. 2001. Sunbirds: a guide to the sunbirds, flowerpeckers, spiderhunters and sugarbirds of the world. Christopher Helm, London, U.K.

Collar, N. J.; Mallari, N. A. D.; Tabaranza, B. R. J. 1999. Threatened birds of the Philippines: the Haribon Foundation/BirdLife International Red Data Book. Bookmark, Makati City, Philippines.

Global Forest Watch. 2020. World Resources Institute. http://www.globalforestwatch.org (Accessed 18 February 2020).

IUCN. 2001. IUCN Red List Categories and Criteria: Version 3.1. IUCN Species Survival Commission. IUCN, Gland, Switzerland and Cambridge, U.K.

IUCN. 2012. IUCN Red List Categories and Criteria: Version 3.1. Second edition. IUCN Species Survival Commission. IUCN, Gland, Switzerland and Cambridge, U.K. www.iucnredlist.org/technical-documents/categories-and-criteria.

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

Joppa, L. N.; Butchart, S. H. M.; Hoffmann, M.; Bachman, S. P.; Akçakaya, H. R.; Moat, J. F.; Böhm, M.; Holland, R. A.; Newton, A.; Polidoro, B.; Hughes, A. 2016. Impact of alternative metrics on estimates of extent of occurrence for extinction risk assessment. Conservation Biology 30: 362-370.

Mohagan, A. B.; Nuñeza, O. M.; Gracia Jr., A. G.; Selpa, E. C. T.;  Escarlos Jr., J. A.; Baguhin, L. J. B.; Coritico, F. P.; Amoroso, V. B. 2015. Species Richness of Avifauna in Four Long Term Ecological Research Sites in Mindanao, Philippines. Journal of Applied Environmental and Biological Sciences 5(11): 88-99.

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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4 Responses to Grey-hooded Sunbird (Aethopyga primigenia): revise global status?

  1. Pete Simpson says:

    I doubt that this would would affect the outcome but I would like to question some of the numbers. “Assuming that the species occurs at a density of 49.1 individuals/km2” (which seems fair), “Grey-hooded Sunbird might number c. 590,000 individuals”, meaning suitable habitat covers 12000km? I would suggest suitable habitat within its range is closer to 2000km or less. Agreed it occurs in forest and on forest edges at altitudes of 1,000-1,700 m but there is little forest remaining 1000-1200masl within much of its range, little within the 1000-1500masl in the Mt Kitanglad range.
    On its range within Mindanao and the resulting AOO, I don’t think that it does occur within about 1/3 of that current area. It does occur in central Mindanao, Mt Apo north to Mt Kitanglad, and north East Mindanao, Mt HilongHilong, but I think that it does not occur south or west of central, in South Cotabato/Sarangani on Mt Matutum, Mt Parker/Mt Busa as reflected in the BirdLife species factsheet distribution map.

  2. 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 ten years approximately 2.1% 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.

  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 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 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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