7 thoughts on “Bahia Antwren (Herpsilochmus pileatus)”
The proposal seems reasonable, and would mean that the categories on the global and national red lists for this Brazilian endemic would be in alignment.
As to whether extrapolating the densities of other congeners to this species is reasonable, I have no field experience of any of them, so am not the best person to opine, but the frequency of records on eBird and WikiAves seems relatively similar for all three species (e.g., in WikiAves, fewer than ten records per municipality in almost all cases for each of the three species).
The largest error in estimating population size using the Global ForestWatch data is probably in how to define “forest”. There is a risk of including areas of degraded forest that do not form suitable habitat for the species. Seeking expert feedback by showing the Global ForestWatch maps to Brazilian observers familiar with the species would be one way to check this.
Also note that the map is apparently incorrect in showing inland areas of distribution. According to Whitney et al. 2000, as well as SALVE and WikiAves, the species does not occur inland. There are inland eBird records, but none have associated media (photos/recordings), and they are likely erroneous, referring to other similar Herpsilochmus species.
As a result of this, the estimate of the EOO from the Brazilian National Red List assessment is 18,808 km2, just 14% of that estimated here. Revision of the range map, EOO and therefore the population estimate is required.
References
Bret M. Whitney, José Fernando Pachecom, Dante R. C. Buzzetti, Ricardo Parrini, Systematic Revision and Biogeography of the Herpsilochmus Pileatus Complex, With Description of a New Species From Northeastern Brazil, The Auk, Volume 117, Issue 4, 1 October 2000, Pages 869–891, https://doi.org/10.1093/auk/117.4.869
NT seems to be suitable for this species. However, data on population size and decline are inferred and suspect, and should not be used for criterion C. On the other hand, according to the national assessment, and Ben Phalan’s comments above, the actual EOO of this species is much smaller than the one shown here. According to ICMBio, the species has an EOO of 18,800 km² and continued decline in habitat quality due to tourism expansion, real estate expansion and silviculture. But its population is not severely fragmented and the number of locations is greater than 10, and thus the species would be NT by criterion B1b(iii).
Many thanks to everyone who has contributed to this discussion. We greatly appreciate the time and effort invested in commenting. The window for consultation is now temporarily closed and we are unable to accept any more comments until 6 February 2023. We will now analyse and interpret new information, and we will post a preliminary decision on this species’ Red List status on this page on 6 February 2023, when discussions will re-open.
Following comments received here, the species’ range map has been revised based on records on WikiAves and eBird. The EOO has been recalculated as 43,800 km2 and the maximum AOO as 9,860 km2. The rate of tree cover loss based on GFW data remained unchanged. However, the population size extrapolated from the area covered by forest is now calculated at 4,200-13,000 mature individuals.
It is noted that the level of data quality is insufficient to justify a listing as threatened under Criterion C. As there is however circumstantial evidence that the population may likely be smaller than 10,000 mature individuals, hence meeting the numerical threshold for a threatened status, with scattered subpopulations and possibly declining at a rate of >10% over ten years based on rates of habitat loss, the species ‘nearly’ qualifies as threatened under Criterion C. In the total absence of any population size numbers, this criterion would not apply. But given that there is data indicating that the thresholds may be met, albeit with some uncertainty, a listing as Near Threatened is justifiable.
Therefore, based on available information, our preliminary proposal for the 2023 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 on 12 February 2023, after which the recommended categorisations will be put forward to IUCN.
The final 2023 Red List categories will be published on the BirdLife and IUCN websites in December 2023, following further checking of information relevant to the assessments by both BirdLife and IUCN.
Many thanks to everyone who has contributed to this discussion. We greatly appreciate the time and effort invested in commenting. The window for consultation is now closed and we are unable to accept any more comments. We will analyse and interpret available information, and we will post a final decision on this species’ Red List status on this page on 20 February 2023.
Recommended categorisation to be put forward to IUCN
The final categorisation for this species has not changed. Bahia Antwren is recommended to be listed as Near Threatened, approaching the threshold for listing as threatened under Criteria C1+2a(i).
Many thanks for everyone who contributed to the 2023.1 GTB Forum process. The final 2023 Red List categories will be published on the BirdLife and IUCN websites in December 2023, following further checking of information relevant to the assessments by both BirdLife and IUCN.
The proposal seems reasonable, and would mean that the categories on the global and national red lists for this Brazilian endemic would be in alignment.
As to whether extrapolating the densities of other congeners to this species is reasonable, I have no field experience of any of them, so am not the best person to opine, but the frequency of records on eBird and WikiAves seems relatively similar for all three species (e.g., in WikiAves, fewer than ten records per municipality in almost all cases for each of the three species).
The largest error in estimating population size using the Global ForestWatch data is probably in how to define “forest”. There is a risk of including areas of degraded forest that do not form suitable habitat for the species. Seeking expert feedback by showing the Global ForestWatch maps to Brazilian observers familiar with the species would be one way to check this.
Also note that the map is apparently incorrect in showing inland areas of distribution. According to Whitney et al. 2000, as well as SALVE and WikiAves, the species does not occur inland. There are inland eBird records, but none have associated media (photos/recordings), and they are likely erroneous, referring to other similar Herpsilochmus species.
As a result of this, the estimate of the EOO from the Brazilian National Red List assessment is 18,808 km2, just 14% of that estimated here. Revision of the range map, EOO and therefore the population estimate is required.
References
Bret M. Whitney, José Fernando Pachecom, Dante R. C. Buzzetti, Ricardo Parrini, Systematic Revision and Biogeography of the Herpsilochmus Pileatus Complex, With Description of a New Species From Northeastern Brazil, The Auk, Volume 117, Issue 4, 1 October 2000, Pages 869–891, https://doi.org/10.1093/auk/117.4.869
SALVE: https://salve.icmbio.gov.br (unavailable files available from ICMBio on request)
NT seems to be suitable for this species. However, data on population size and decline are inferred and suspect, and should not be used for criterion C. On the other hand, according to the national assessment, and Ben Phalan’s comments above, the actual EOO of this species is much smaller than the one shown here. According to ICMBio, the species has an EOO of 18,800 km² and continued decline in habitat quality due to tourism expansion, real estate expansion and silviculture. But its population is not severely fragmented and the number of locations is greater than 10, and thus the species would be NT by criterion B1b(iii).
Many thanks to everyone who has contributed to this discussion. We greatly appreciate the time and effort invested in commenting. The window for consultation is now temporarily closed and we are unable to accept any more comments until 6 February 2023. We will now analyse and interpret new information, and we will post a preliminary decision on this species’ Red List status on this page on 6 February 2023, when discussions will re-open.
Preliminary proposal
Following comments received here, the species’ range map has been revised based on records on WikiAves and eBird. The EOO has been recalculated as 43,800 km2 and the maximum AOO as 9,860 km2. The rate of tree cover loss based on GFW data remained unchanged. However, the population size extrapolated from the area covered by forest is now calculated at 4,200-13,000 mature individuals.
It is noted that the level of data quality is insufficient to justify a listing as threatened under Criterion C. As there is however circumstantial evidence that the population may likely be smaller than 10,000 mature individuals, hence meeting the numerical threshold for a threatened status, with scattered subpopulations and possibly declining at a rate of >10% over ten years based on rates of habitat loss, the species ‘nearly’ qualifies as threatened under Criterion C. In the total absence of any population size numbers, this criterion would not apply. But given that there is data indicating that the thresholds may be met, albeit with some uncertainty, a listing as Near Threatened is justifiable.
Therefore, based on available information, our preliminary proposal for the 2023 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 on 12 February 2023, after which the recommended categorisations will be put forward to IUCN.
The final 2023 Red List categories will be published on the BirdLife and IUCN websites in December 2023, following further checking of information relevant to the assessments by both BirdLife and IUCN.
Many thanks to everyone who has contributed to this discussion. We greatly appreciate the time and effort invested in commenting. The window for consultation is now closed and we are unable to accept any more comments. We will analyse and interpret available information, and we will post a final decision on this species’ Red List status on this page on 20 February 2023.
Recommended categorisation to be put forward to IUCN
The final categorisation for this species has not changed. Bahia Antwren is recommended to be listed as Near Threatened, approaching the threshold for listing as threatened under Criteria C1+2a(i).
Many thanks for everyone who contributed to the 2023.1 GTB Forum process. The final 2023 Red List categories will be published on the BirdLife and IUCN websites in December 2023, following further checking of information relevant to the assessments by both BirdLife and IUCN.