Black-breasted Puffleg (Eriocnemis nigrivestis): revise global status?

BirdLife species factsheet for Black-breasted Puffleg

Black-breasted Puffleg (Eriocnemnis nigrivestis) is endemic to Ecuador, occurring in the highlands of Pichincha, Esmeraldas and Imbabura provinces. The majority of records come from the northwestern ridge-crests of Pichincha volcano, west of Quito. In 2006, a small population was rediscovered in the Cordillera de Toisán above the Intag valley (Jahn 2008). A recent survey found that this population still persists, albeit in low numbers (Aves y Conservación 2018). The total population is estimated to number 210-268 individuals, roughly equating to 140-180 mature individuals (Jahn 2008). Sightings on the Atacazo volcano south-west of Quito could not be confirmed; however, it is possible that a small population will occur there.

Black-breasted Puffleg inhabits humid and wet montane cloud forest at 1,700-3,500 m (Jahn 2008, Jahn and Santander 2008). The species has occasionally been recorded along bushy forest edges along road sides, steep slopes with stunted vegetation and from taller montane forest interiors and clearings (Bleiweiss and Olalla 1983, Santander et al. 2004, Jahn 2008, Jahn and Santander 2008). However, recent research suggests that the species strongly avoids edge habitats (Guevara et al. 2015). Black-breasted Puffleg undergoes seasonal altitudinal migrations, which are thought to be determined by the flowering of specific vines and species such as fuchsias and ericaceous trees (Bleiweiss and Olalla 1983).

The species is suspected to have suffered drastic declines owing to habitat loss within its small range and is now rare (Phillips 1998). Around 93% of suitable habitat within its probable historic range has been degraded or destroyed (Williams and Santander 2003). The main threat is the logging of forest for timber, charcoal and mining concessions, facilitating the introduction of cattle and the spread of the agricultural frontier (Phillips 1998, Santander et al. 2004, Jahn 2008). Additionally, human-induced fires threaten large tracts of forest during the dry season (Jahn 2008). In the future, climate change may render remaining habitat unsuitable (Jahn and Santander 2008) and push the species above the current treeline (Jahn 2008), which could lead to increased competition with Gorgeted Sunangel (Heliangelus strophianus) (Jahn 2008, Guevara 2013).

Black-breasted Puffleg is currently listed as Critically Endangered under Criterion B1ab(i,ii,iii,v), indicating a very small Extent of Occurrence (EOO). However, already in 2008 it has been suggested that classifying the species as Critically Endangered may be too precautionary (Jahn 2008). It has further been recommended that downlisting might be appropriate, pending that the persistence of the population in the Cordillera de Toisán be confirmed. The recent discovery of a pair of Black-breasted Puffleg in this area (Aves y Conservación 2018) confirms this condition.

Following IUCN guidelines, the EOO for this species has been re-calculated using a Minimum Convex Polygon (IUCN 2001, 2012, Joppa et al. 2016). A Minimum Convex Polygon is defined as “the smallest polygon in which no internal angle exceeds 180 degrees and which contains all the sites of occurrence” (IUCN 2001, 2012). For a species occurring in several discrete patches, this would still take the form of one continuous area, rather than separate polygons, as such disjunctions are ‘strongly discouraged’ by IUCN (IUCN Petitions and Standards Subcommittee 2017). This is because using separate, discrete polygons would not accurately reflect how a large range size reduces the global impact on a species from local processes.

After re-calculating the EOO for Black-breasted Puffleg, this species appears to warrant a change in Red List status. Therefore, we present here our reassessment against all criteria for the species.

The initial topic on this analysis can be found here.

Criterion A – The population of Black-breasted Puffleg is considered to be in decline based on habitat loss within its range, the rate of which is likely lower than 10% over three generations (12.6 years) (Santander et al. 2004, Cárdenas 2007, O. Jahn in litt. 2007, Tracewski et al. 2016). Therefore, Black-breasted Puffleg may be listed as Least Concern under this criterion.

Criterion B – The species is known from the slopes of the Pichincha volcano and in the Cordillera de Toisán. Using a Minimum Convex Polygon, the Extent of Occurrence (EOO) of this species has been calculated as 700 km2, which meets the threshold for listing as Endangered under Criterion B1. The Area of Occupancy (AOO) has not been quantified, and therefore the species cannot be assessed against Criterion B2. However, in order to be listed as threatened under Criterion B, at least two further conditions have to be met.

In view of our current knowledge about the distribution of the species, we can assume that the two known areas of occurrence of Black-breasted Puffleg represent two separate locations* sensu IUCN, which meets the threshold for Endangered under condition (a). The EOO, AOO, habitat quality and population size of Black-breasted Puffleg are in decline, meeting the threshold under condition b(i,ii,iii,v). Black-breasted Puffleg is not known to undergo extreme fluctuations, thus condition (c) is not met. Overall, the species may be listed as Endangered under Criterion B1ab(i,ii,iii,v).

Criterion C – The population of Black-breasted Puffleg is estimated to number 140-180 mature individuals. This estimate appears very precautionary and the true population size may be larger (Jahn 2008). However, based on currently available information, it may warrant listing Black-breasted Puffleg under Criterion C, given the species is considered to be declining, as long as other conditions are met. To be listed under Criterion C1 would require Black-breasted Puffleg to be undergoing a decline of at least 10 % over three generations. As the rate of decline for this species is not known, but likely lower than 10% over this timeframe (Santander et al. 2004, Cárdenas 2007, O. Jahn in litt. 2007, Tracewski et al. 2016), it cannot be assessed against Criterion C1.

Black-breasted Puffleg is known from two locations* on Pichincha Vulcano and outside Cotocachi-Cayapas Ecological Reserve in Toisán. Pichincha is believed to support around 160 individuals (Jahn 2008), equalling about 110 mature individuals. The size of the subpopulation of Toisán has not been estimated, but is likely smaller. Jahn (2008) suggested that this subpopulation numbers 48-108 individuals, equalling about 30-70 mature individuals. This means that, while the global population numbers likely less than 250 mature individuals, the largest subpopulation contains more than 50 mature individuals and thus, the conditions for listing the species as Critically Endangered under this criterion are not met. However, as no subpopulation holds more than 250 mature individuals, Black-breasted Puffleg may be listed as Endangered under Criterion C2a(i).

Criterion D – The population size of this species is estimated at 140-180 mature individuals. Therefore, it may be listed as Endangered under Criterion D.

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 proposed that Black-breasted Puffleg (Eriocnemis nigrivestis) be listed as Endangered under Criteria B1ab(i,ii,iii,v); C2a(i); D. We welcome any comments on this proposed listing and specifically request up-to-date information on the size of the subpopulations of Black-breasted Puffleg.

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.

*Note that 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 subpopulations. Where a taxon is affected by more than one threatening event, location should be defined by considering the most serious plausible threat (IUCN 2001, 2012).

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

Aves y Conservación. 2018. Se registra nuevamente al Zamarrito Pechinegro en Imbabura. http://avesconservacion.org/web/se-registra-nuevamente-al-zamarrito-pechinegro-en-imbabura/ (Accessed 18/03/2019).

Bleiweiss, R.; Olalla, M. 1983. Notes on the ecology of the Black-breasted Puffleg on Volcan Pichincha, Ecuador. Wilson Bulletin 94: 656-661.

Guevara, E.A. 2013. Multi-scale habitat use analysis and interspecific ecology of the Critically Endangered Black-breasted Puffleg, Eriocnemis nigrivestis. MSc Thesis. Faculty of Science, University of Amsterdam, Amsterdam, The Netherlands.

Guevara, E.A.; Bonaccorso, E.; Duivenvoorden, J.F. 2015. Multi-scale habitat use analysis and interspecific ecology of the Critically Endangered Black-breasted Puffleg Eriocnemis nigrivestis. Bird Conservation International: 1-10.

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 Subcommittee. 2017. Guidelines for Using the IUCN Red List Categories and Criteria. Version 13. Prepared by the Standards and Petitions Subcommittee. http://www.iucnredlist.org/documents/RedListGuidelines.pdf

Jahn, O. 2008. Rediscovery of Black-breasted Puffleg Eriocnemis negrivestis in the Cordillera de Toisán, north-west Ecuador, and reassessment of its conservation status. Cotinga: 31-39.

Jahn, O.; Santander, T. 2008. Species action plan: Black-breasted Puffleg Eriocnemis nigrivestis. Aves & Conservación, Quito, Ecuador.

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.

Phillips, R. 1998. Red Data Bird: Black-breasted Puffleg Eriocnemis nigrivestis. World Birdwatch 20: 20-21.

Santander, T.; Tellkamp, M.P.; Williams, R.; Davidson, I.J. 2004. Conserving the globally threatened Black-breasted Puffleg Eriocnemis nigrivestis. BirdLife International, Quito, Ecuador.

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.

Williams, R.; Santander, T. 2003. Conservation of the Black-breasted Puffleg Eriocnemis nigrivestis: A review of the species’ range and ecology, mapping of remaining habitat and proposal for the species’ conservation.

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8 Responses to Black-breasted Puffleg (Eriocnemis nigrivestis): revise global status?

  1. Tatiana Santander says:

    Dear BirdLife International Red List Team,

    We have reviewed the document. Hereby, my colleagues and I, want to share our comments concerning this reasoning and the information that it is provided to support this proposal.

    “Black-breasted Puffleg inhabits humid and wet montane cloud forest at 1,700-3,500 m”
    We think it should be specified that the common range of this species is between 3000 to 3500 m, there is one anecdotal record of one individual at 1700 m at reserva Las Gralarias. Even now the BBP is not very common at Yanacocha reserve (3500 m), where there has been some years with one or few records. The Puffleg is a species which might be not easily overlooked at these reserves, since birdwatchers constantly visit the area looking for Pufflegs and other hummingbirds and observation reports through online platforms as e-Bird is encouraged. Furthermore, Aves y Conservación, in collaboration with the Swiss Federal Research Institute WSl, has been carrying out hummingbird observations at these reserves along a wide elevation gradient, including Yanacocha, Las Gralarias and Alaspungo. After two years of field observations we have only recorded the species at Verdecocha reserve at 3200 m and adjacent to Yanacocha. In sum we strongly suggest that any further estimation of EOO or AOO should be done considering the very narrow altitudinal range that the species actually occupies i.e. 3000-3500

    “Around 93% of suitable habitat within its probable historic range has been degraded or destroyed”
    The suitable habitat loss is estimated to be at 93%, this information contrast with the estimation of an EOO of 700 km2 as a criterion to downlist the category of this species. In addition the area considered as EOO most likely includes historic records and areas that currently does not hold suitable habitat or where the species is not currently present.

    Application of Criterion B

    “Using a Minimum Convex Polygon, the Extent of Occurrence (EOO) of this species has been calculated as 700 km2”
    We think the EOO of 700 km2 is overestimating the potential occurrence of the BBP, as UICN mentioned this calculation should be done considering “the known sites of present occurrence of a taxon, excluding cases of vagrancy”. Jahn (2008) also calculated a suitable estimated habitat of 139 km2 which for us is a more accurate approximation. We also consider that in this particular case a more reliable criterion to assess the risk of extinction could be the Area of Occupancy (AOO) i.e. the portion within the EOO that is actually known to be occupied by the species, excluding discontinuities in its distribution. Based on current vegetation maps, elevation shapefiles and georeferenced points we have determined that the current known area occupied by the species is not larger than 10 km2, which is the threshold determined by IUCN.

    “In view of our current knowledge about the distribution of the species, we can assume that the two known areas of occurrence of Black-breasted Puffleg represent two separate locations* sensu IUCN, which meets the threshold for Endangered under condition (a)”
    We agree there are now two locations for the species (Pichincha and Toisán subpopulations) which disqualifies the criterion B(a) for Number of locations but still it could be considered the criterion B(a) for Severely fragmented.

    In conclusion, we recommend to apply the Area of Occupancy as criterion to assess risk of extinction for the Pufflegs and to consider a precautionary position regarding this species since current mining policies of Ecuadorian government could largely affect the northernmost subpopulation at Intag Toisán area. Similarly we agree with Jahn (2008) that in the event that an additional locality is discovered the species could be downlisted as Endangered. Note that Aves y Conservación will carry out expeditions at Imbabura province during next year. Finally please feel free to contact us for further information about the species.

    • Red List Team (BirdLife International) says:

      Thank you very much for your comment. In the following, we will address the issues you raised.
      Elevation range: We can confirm that the range map produced by BirdLife International only includes areas between 3,000 and 3,500 m. Consequently, all calculations for EOO and AOO are based on this range.
      Habitat availability: The EOO is a purely spatial measure, which does not take into account the amount of suitable habitat within and is consequently independent of the population density. Therefore, based on IUCN guidelines, the EOO may well include areas of unsuitable habitat (please see https://nc.iucnredlist.org/redlist/resources/files/1539098236-Mapping_Standards_Version_1.16_2018.pdf chapter 7.1). It however does not include areas where the species is considered to be “possibly extant” or “possibly extinct”.
      Calculation of EOO: The EOO is not equivalent to the mapped range. It is a measure of the spatial spread of the extinction risk. According to IUCN guidelines (see link above), the EOO is calculated as a Minimum Convex Polygon around “all known, inferred or projected sites of occurence of a taxon”. It needs to be mapped as only one polygon around all areas of mapped range. The guidelines explicitly state that no exceptions are allowed for taxa with disjunct subpopulations, as is the case for the Black-breasted Puffleg. This also implies that no areas of unsuitable habitat can subsequently be deleted from the EOO.
      Severe fragmentation: To qualify as severely fragmented, more than half of the global population needs to be found in “small and relatively isolated subpopulations”. This is not the case for the Black-breasted Puffleg, as this species forms two (relatively) large subpopulations.
      Final Red List assessment: BirdLife generally uses a precautionary approach by basing the assessment on the most pessimistic estimate for the respective criteria. We are obliged to assess a species against all criteria that data availability allows, we cannot pre-select a criterion that seems most plausible.
      Calculation of AOO: Currently, we do not have information to calculate the AOO of the species, and consequently we cannot assess it against Criterion B2. If you have the data, would you please share it with us? Thank you!

  2. Juan Freile says:

    In the recent update of Ecuador’s red list, we largely discussed about this species’ EOO. Even though downgrading it to EN is clearly justified by a re-calculated EOO larger than the threshold for CR, we suspect this decision will underestimate the actual status of this narrowly endemic species.
    Following IUCN guidelines and recommendations, we excluded areas of unsuitable habitat for calculating its EOO. The intervening area between volcán Pichincha and Toisán is largely unsuitable for this elfin and montane forest species. Our estimate of EOO resulted in c. 70 km2, which is still below the threshold for CR.
    The most experienced researchers with this species (Esteban Guevara, Tatiana Santander and colleagues) supported our evaluation. In fact, both Santander and Guevara are members of the Ecuador red list team.

    • Red List Team (BirdLife International) says:

      Thank you very much for your comment. IUCN guidelines state that the EOO has to be mapped as a Minimum Convex Polygon around the area of mapped range. The guidelines stress that this polygon needs to be continuous, and that no exceptions can be made for species with disjunct ranges. This implies that for the Black-breasted Puffleg, the EOO will include areas of unsuitable habitat, which cannot be excluded. Please see https://www.iucnredlist.org/resources/redlistguidelines chapter 4.9 for details. The EOO measures the spatial spread of the areas occupied by the taxon, i.e. the spatial spread of the extinction risk. It does not measure the amount of occupied or suitable habitat.

  3. Red List Team (BirdLife International) says:

    Preliminary proposal
    Based on available information, our preliminary proposal for the 2019 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 2019 Red List categories will be published on the BirdLife and IUCN websites in December, following further checking of information relevant to the assessments by both BirdLife and IUCN.

  4. I disagree with down-listing to EN. In particular, criterion C does not warrant down-listing. I believe it is wrong to base the population estimate on the dated Jahn 2008 reference, when more recent research from Esteban Guevara, Tatiana Santander et al. from the Vulcano Pichincha have yielded comparatively few records given the observation efforts. There are no data to support a population of 160 individuals on the western slopes of Vulcano Pichincha. Effectively, there are only two sites here where Black-breasted Pufflegs can be reliably recorded. At each site, few individuals are encountered.
    There is no indication that the largest subpopulation numbers >50 mature individuals. For all we know, it may well be less than that.

    • Red List Team (BirdLife International) says:

      Thank you for your comment and contribution to the re-assessment of Black-breasted Puffleg. We would be happy to review the results from recent research on the species. In order to thoroughly assess its Red List status, we rely on species experts to share the results of their studies with us. Particularly in the case of Black-breasted Puffleg, any new information on population size and structure is vital. Would you please share the population estimates? Thank you very much.

  5. Red List Team (BirdLife International) says:

    Recommended categorisations to be put forward to IUCN
    Based on available information, our proposal for the 2019 Red List is to pend the decision on this species and keep the discussion open until 2020, while leaving the current Red List category unchanged in the 2019 update.
    Final 2019 Red List categories will be published on the BirdLife and IUCN websites in December, following further checking of information relevant to the assessments by both BirdLife and IUCN.

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