9 thoughts on “Van Dam’s Vanga (Xenopirostris damii)”
I dont necessarily disagree with the proposed status change. Just a quick note to say that the species is certainly still present in Mariarano (it was observed this summer, 2024) although it remains a very rare, seldom recorded species and certainly does not approach the population densities reported from other sites (that are reported here). Although I see the summary (prudently) already takes that into account.
Notably, the species has never been detected in the Matsedroy dry forest (c. 5km from Mariarano), even after >10 years of seasonal surveys here. Its absence from Matsedroy as stated in the Long et al. references you already cite still applies in 2024. So its likely the case that the species does not inhabit all forest patches with potentially suitable habitat within its range.
Its also worth noting that Mariarano continues to experience habitat degradation, and perhaps more pertinently, so does the species stronghold in Ankarafantsika, where there are (amongst other concerns) increasing issues with fire damage. This recent paper might be useful in that regard: https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0290203
The species has been repeatedly seen in Mariarano, suggesting a potentially self-sustaining subpopulation, but given the size of the available forest there, the subpopulation size is not going to be large (tens to hundreds of individuals I would suspect, rather than anything more significant).
There are wide areas of unsuitable habitat between Mariarano and Ankarafantsika, and only small patches of forest so proper connectivity is suspected to be unlikely now, but historically it probably would have been connected as a single subpopulation.
The Long et al. references could potentially be removed as the records from that site are summarised in Rasamison et al. (2018) – but don’t include unpublished records from there from 2010 (there might be a sound record out there from 2010, but no photographic records that I am aware of).
My gut feeling is that the total population size estimate may be a bit high – as the Mizuta et al. (2001) densities were considered ‘an optimistic minimum’ in the past, but with the habitat fragmentation I would not expect it to be in a single subpopulation any more, but the numbers do suggest that, whatever, the subpopulation at ANP would be >1,000 mature individuals; so VU under A is probably fair
I am unable to comment on the numbers and therefore the status change proposed, but just to note that there is a frequently overlooked possibility that the species also occurs in mangroves and is therefore more abundant than we currently think. If anything, this adds weight to the downlisting argument. As far as I know, there hasn’t been any dedicated survey effort for the species in the fairly extensive mangroves of Madagascar’s north-west coast. See:
Woolaver, L., Nichols, R., Razafindrajao, F. and Hawkins, A.F.A. (2004). Sighting of Van Dam’s Vanga Xenopirostris damii (Schlegel, 1866) in mangroves in north-west Madagascar. Bull. Brit. Orn. Club 124(1): 69–71.
Just to quickly follow-up on Simon’s comment, there has been extensive survey effort in the mangroves of the Ankobohobo wetlands, adjacent to the Mariarano forests (eight years of seasonal surveys), and the species has never been detected there (see Ó Marcaigh et al. 2020; https://www.ajol.info/index.php/scopus/article/view/198313) but that is not to say it definitely does not occur in mangroves elsewhere (indeed the reference in Simons comment suggests it can occur in these habitats).
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 until 28 October 2024. We will now analyse and interpret the information, and we will post a preliminary decision on this species’ Red List status on this page on 28 October 2024, when discussions will re-open.
Thank you all very much for your comments. Based on available information, our preliminary proposal for the 2025 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 10 November 2024, after which the recommended categorisations will be put forward to IUCN.
The final Red List categories will be published on the BirdLife and IUCN websites in 2025, following further checking of information relevant to the assessments by both BirdLife and IUCN.
Species were recorded three Times AT Bongola a forest during environnemental survey conducted through PAG(Projet d’appui pour la gestion de l’environnement) funded by USAID…2000. Rapport documents are available AT Conservation l’international and ZICOMA (l’important Bird Area for Madagascar project calling actually ASITy….l think thés records need to bé Taken in considération as l did thé survey ans l confirm Vandam’s présence AT Bongola a with photography évidence.
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 the information, and a final decision on this species’ Red List category will be posted on this page on 18 November 2024.
Recommended categorisation to be put forward to IUCN
Thank you, Marc, for your input on the species’ distribution. This forest has now been incorporated into the species’ mapped range. Also, thank you Tom for highlighting the species’ absence in the Matsedroy dry forest, despite numerous surveys over the past decade. This forest has now been removed from the species’ extant range.
These map updates did not significantly impact the overall rate of forest cover loss (Global Forest Watch 2024), and as a result, the category and criteria for the species’ assessment remain unchanged.
The final categorisation for this species has not changed. Van Dam’s Vanga is recommended to be listed as Vulnerable under Criteria A2c+3c+4c.
Many thanks for everyone who contributed to the 2025.1 GTB Forum process. The final Red List categories will be published on the BirdLife and IUCN websites in 2025, following further checking of information relevant to the assessments by both BirdLife and IUCN.
I dont necessarily disagree with the proposed status change. Just a quick note to say that the species is certainly still present in Mariarano (it was observed this summer, 2024) although it remains a very rare, seldom recorded species and certainly does not approach the population densities reported from other sites (that are reported here). Although I see the summary (prudently) already takes that into account.
Notably, the species has never been detected in the Matsedroy dry forest (c. 5km from Mariarano), even after >10 years of seasonal surveys here. Its absence from Matsedroy as stated in the Long et al. references you already cite still applies in 2024. So its likely the case that the species does not inhabit all forest patches with potentially suitable habitat within its range.
Its also worth noting that Mariarano continues to experience habitat degradation, and perhaps more pertinently, so does the species stronghold in Ankarafantsika, where there are (amongst other concerns) increasing issues with fire damage. This recent paper might be useful in that regard: https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0290203
The species has been repeatedly seen in Mariarano, suggesting a potentially self-sustaining subpopulation, but given the size of the available forest there, the subpopulation size is not going to be large (tens to hundreds of individuals I would suspect, rather than anything more significant).
There are wide areas of unsuitable habitat between Mariarano and Ankarafantsika, and only small patches of forest so proper connectivity is suspected to be unlikely now, but historically it probably would have been connected as a single subpopulation.
The Long et al. references could potentially be removed as the records from that site are summarised in Rasamison et al. (2018) – but don’t include unpublished records from there from 2010 (there might be a sound record out there from 2010, but no photographic records that I am aware of).
My gut feeling is that the total population size estimate may be a bit high – as the Mizuta et al. (2001) densities were considered ‘an optimistic minimum’ in the past, but with the habitat fragmentation I would not expect it to be in a single subpopulation any more, but the numbers do suggest that, whatever, the subpopulation at ANP would be >1,000 mature individuals; so VU under A is probably fair
I am unable to comment on the numbers and therefore the status change proposed, but just to note that there is a frequently overlooked possibility that the species also occurs in mangroves and is therefore more abundant than we currently think. If anything, this adds weight to the downlisting argument. As far as I know, there hasn’t been any dedicated survey effort for the species in the fairly extensive mangroves of Madagascar’s north-west coast. See:
Woolaver, L., Nichols, R., Razafindrajao, F. and Hawkins, A.F.A. (2004). Sighting of Van Dam’s Vanga Xenopirostris damii (Schlegel, 1866) in mangroves in north-west Madagascar. Bull. Brit. Orn. Club 124(1): 69–71.
Just to quickly follow-up on Simon’s comment, there has been extensive survey effort in the mangroves of the Ankobohobo wetlands, adjacent to the Mariarano forests (eight years of seasonal surveys), and the species has never been detected there (see Ó Marcaigh et al. 2020; https://www.ajol.info/index.php/scopus/article/view/198313) but that is not to say it definitely does not occur in mangroves elsewhere (indeed the reference in Simons comment suggests it can occur in these habitats).
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 until 28 October 2024. We will now analyse and interpret the information, and we will post a preliminary decision on this species’ Red List status on this page on 28 October 2024, when discussions will re-open.
Preliminary proposal
Thank you all very much for your comments. Based on available information, our preliminary proposal for the 2025 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 10 November 2024, after which the recommended categorisations will be put forward to IUCN.
The final Red List categories will be published on the BirdLife and IUCN websites in 2025, following further checking of information relevant to the assessments by both BirdLife and IUCN.
Species were recorded three Times AT Bongola a forest during environnemental survey conducted through PAG(Projet d’appui pour la gestion de l’environnement) funded by USAID…2000. Rapport documents are available AT Conservation l’international and ZICOMA (l’important Bird Area for Madagascar project calling actually ASITy….l think thés records need to bé Taken in considération as l did thé survey ans l confirm Vandam’s présence AT Bongola a with photography évidence.
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 the information, and a final decision on this species’ Red List category will be posted on this page on 18 November 2024.
Recommended categorisation to be put forward to IUCN
Thank you, Marc, for your input on the species’ distribution. This forest has now been incorporated into the species’ mapped range. Also, thank you Tom for highlighting the species’ absence in the Matsedroy dry forest, despite numerous surveys over the past decade. This forest has now been removed from the species’ extant range.
These map updates did not significantly impact the overall rate of forest cover loss (Global Forest Watch 2024), and as a result, the category and criteria for the species’ assessment remain unchanged.
The final categorisation for this species has not changed. Van Dam’s Vanga is recommended to be listed as Vulnerable under Criteria A2c+3c+4c.
Many thanks for everyone who contributed to the 2025.1 GTB Forum process. The final Red List categories will be published on the BirdLife and IUCN websites in 2025, following further checking of information relevant to the assessments by both BirdLife and IUCN.