Greater Crescent-chested Puffbird (Malacoptila striata): revise global status?

BirdLife species factsheet for Greater Crescent-chested Puffbird

The Greater Crescent-chested Puffbird (Malacoptila striata) occurs in the Atlantic Forests of eastern and south-eastern Brazil, between southern Bahia and Santa Catarina (del Hoyo et al. 2002). It inhabits the understorey of humid lowland forest, ranging up to 2,100m; it tolerates logged forest, secondary growth, forest edges with grass and bamboo groves, and is often found at the edges of clearings or along roads (Aleixo & Galetti 1997, del Hoyo et al. 2002, WikiAves 2014, V. Cavarzere in litt. 2020). It feeds on insects and small arthropods and has been observed taking prey at an army ant swarm (WikiAves 2014). This species occupies a range that has been heavily deforested; forest loss in this region is said to have been particularly severe since the early 1970s (Tabarelli et al. 2005).

Greater Crescent-chested Puffbird is currently listed as Near Threatened because it was thought that its rate of population decline may have been approaching the thresholds for threatened status under Criterion A2c+3c+4c. However, recent data on deforestation within the range suggests that it may be declining less rapidly than previously thought. Hence, we are undertaking a review of the species’s Red List Category.

Criterion A – The species’s generation length has recently been re-estimated to be 3.2 years, using the methodology of Bird et al. (2020)*, as applied to parameter values updated for the current Red List assessment cycle. Therefore, reductions are here calculated over a period of ten years.

Based on data from Global Forest Watch, 7.5% of forest with at least 30% canopy cover was lost over ten years from 2008 to 2018 within the range (Global Forest Watch 2020). The species is tolerant of modified habitats. Furthermore, a detailed analysis of forest loss data within a municipality in the Atlantic Forest region has indicated that less than 30% of the area classified as forest loss was correctly classified (Andreacci & Marenzi 2020). The species is therefore suspected to have undergone a reduction of 1-8% over the past ten years. From 2013-2018, the year with the largest amount of deforestation within the species’s range was 2017, with 3,130 km2 of forest lost (Global Forest Watch 2020). If this amount of forest loss were to continue over ten years, it would result in 10% forest loss over the period. Taking this rate as a worst-case estimate, the species is suspected to undergo a population reduction of 1-10% over the next ten years. These magnitudes of reduction do not approach the thresholds for listing the species as threatened under Criterion A. Greater Crescent-chested Puffbird is therefore assessed as Least Concern under this criterion.

To be downlisted to a lower category of threat, the species must not have qualified for the higher category for at least five years. Based on data from Global Forest Watch, only 6.8% of forest with at least 30% canopy cover within the species’s range was lost over ten years from 2005-2015 (Global Forest Watch 2020).

Criterion B – The Extent of Occurrence (EOO), inferred from the area of a minimum convex polygon around the species’s mapped range, is 1,090,000 km2. This does not approach the threshold for listing the species as threatened under Criterion B1. The Area of Occupancy (AOO) has not been quantified. Based on the large area of the species’s mapped range (707,000 km2) and an estimated area of tree cover (with at least 30% canopy cover) within the range of 289,000 km2 in 2010 (Global Forest Watch 2020), the AOO is unlikely to approach the threshold for threatened status under Criterion B2. The species is therefore assessed as Least Concern under Criterion B.

Criterion C – The population size and density have not been directly estimated, but surveys have indicated that the species is uncommon within its range (Stotz et al. 1996, Aleixa & Galetti 1997, Goerck 1999). Based on the minimum and first quartile population densities of congeners (0.65 and 1.5 individuals per km2, respectively), the area of forest with at least 30% canopy cover within the species’s mapped range (289,000 km2; Global Forest Watch 2020), and assuming that between 25% and 45% of the area of forest is occupied, the population size is suspected to be between 107,000 and 193,000 individuals. This roughly equates to 72,000 – 129,000 mature individuals. The population size hence does not approach the threshold for listing as threatened under Criterion C. Greater Crescent-chested Puffbird is therefore assessed as Least Concern under this criterion.

Criterion D – Based on the estimates described above, the population size does not meet or approach the threshold for Vulnerable under Criterion D. The species is therefore assessed as Least Concern under this criterion.

Criterion E – To the best of our knowledge no quantitative assessment of the probability of extinction has been conducted for this species, and so it cannot be assessed against this criterion.

Based on the above assessment, it is proposed to list the Greater Crescent-chested Puffbird (Malacoptila striata) as Least Concern. We welcome any comments to the proposed listing. Information is particularly requested on the rate of decline and the impact of threats on the population size.

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’s Red List status. Therefore, please make sure your comments are about the proposed listing. 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

Aleixo, A. and Galetti, M. 1997. The conservation of the avifauna in a lowland Atlantic forest in south-east Brazil. Bird Conservation International 7: 235-261.

Andreacci, F., & Marenzi, R. C. 2020. Accounting for twenty-first-century annual forest loss in the Atlantic Forest of Brazil using high-resolution global maps. International Journal of Remote Sensing 41(11): 4408-4420.

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

del Hoyo, J.; Elliott, A.; Sargatal, J. 2002. Handbook of the Birds of the World, vol. 7: Jacamars to Woodpeckers. Lynx Edicions, Barcelona, Spain.

Global Forest Watch. 2020. Interactive Forest Change Mapping Tool. Available at: http://www.globalforestwatch.org/.

Goerck, J. M. 1999. Distribution of birds along an elevational gradient in the Atlantic forest of Brazil: implications for the conservation of endemic and endangered species. Bird Conservation International 9: 235-253.

Stotz, D.F.; Fitzpatrick, J.W.; Parker, T.A.; Moskovits, D.K. 1996. Neotropical Birds: Ecology and Conservation. University of Chicago Press, Chicago.

Tabarelli, M.; Pinto, L. P.; DA Silva, J. M. C.; Hirota, M.; Bede, L. 2005. Challenges and opportunities for biodiversity conservation in the Brazilian Atlantic Forest. Conservation Biology 19(3): 695-700.

WikiAves. 2014. Barbudo-rajado. Available at: http://www.wikiaves.com/barbudo-rajado.

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4 Responses to Greater Crescent-chested Puffbird (Malacoptila striata): revise global status?

  1. Hannah Wheatley (BirdLife) 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, 7.5% of tree cover with at least 30% canopy cover within the species’s range was lost over ten years from 2009-2019 (Global Forest Watch 2020). This new information does not affect the suspected population reduction over the past ten years, or over ten years into the future.

  2. Diego Lima says:

    In the National (Brazil) assessment carried out in 2019 composed of the following team of researchers: Ciro Ginez Albano, Glayson Ariel Bencke, José Fernando Pacheco, Luís Fábio Silveira, Vítor de Queiroz Piacentini and Wagner Nogueira Alves, verified the IUCN criteria and classified the species as Least Concern.

    The species, however, is reasonably common and to some extent tolerant to habitat change; its distribution range is large including considerable portions of suitable habitat; therefore no current threats are known that would indicate risk of extinction in the near future.

    Malacoptila striata striata is reasonably common (Evaluation Workshop Plenary 2019), but population data are not available (Rasmussen & Collar 2002).

  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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