24 thoughts on “Oriental Darter (Anhinga melanogaster)”
I don’t agree with the proposed category of least concern. It’s population is still on declining trend. And it should be categorized as near threatened.
I also do not agree with being the least concerned, because the population has gradually been in a declining situation owing to the decline of the wetland habitat as well as their insufficient fish food species in previously potential sites. It was also evident during the 2024 AWC bird count in protected areas.
I do not want to agree with being the least concerned, instead proposed to include the species as near-threatened owing to the drastic decline of the population status in the Northeastern region of India.
Downgrading to Least Concerned, instead of keeping or including the species as near-threatened owing, doesn’t make a proper sense given the drastic decline of the population status actoss the Indian SubContinent
This bird is still not a commonly sighted species,given that it’s very habitat specific bird ,and it’s population trends doesn’t require it to be addressed as least concern
I do no know the current status and population of Oriental Darter , but in case of Nepal, it should be considered as Near Threatened as its population is in declining trend.
In Southeast Asia, at least in Cambodia, Oriental Darter has undergone a dramatic population increase, which is evidenced both by annual systematic population monitoring data from the largest colony (at Prek Toal on the Tonle Sap Lake) and just by casual birding records. The species has gone from one that was rarely sighted away from Prek Toal to one that is commonly seen in wetlands across the country. It now breeds at many wetland sites. In the context of population trends in this part of its range (which must constitute most of the world population) it is inconceivable that it is anything other than Least Concern.
We received the following contribution from Fred Goes:
“I looked at the species to review for Asia, and my expertise being about Cambodia, it concerns only WWDuck and ODarter.
Overall I fully agree with your proposed category change, with only one caveat.
For ODarter, there has been no available data since 2013 on the trend and population for the Prek Toal colony, Tonle Sap, which is the species stronghold in SEAsia ! At the time, the colony was fluctuating yearly between 5,000-7,000 pairs (2008-2012, WCS data in Goes 2014).
I hope that my former WCS colleagues can provide more recent pop data, as well as information on eventual spill-over colonies around the Tonle Sap or further away in Cambodia.”
About 30 water bodies surveyed around keoladeo national Park in Rajasthan between 2004-2007. Except few sites all had no presence of Oriental darter. In keoladeo national Park, one of largest heronry in Asia they are also declining trend. It is therefore considered at least near threatened.
Prior to 1994, the species was uncommon in Bangalore with only three sight records over a decade. However, the situation changed from mid 1990 onwards when the lakes of Bangalore were leased out for commercial fishing and the lakes were seeded with fish species like Rohu (Labeo rohita), Catla (Catla catla)and Tilapia (Oreochromis sp.). Today the species is seen small numbers in lakes of Bangalore and also breeds at several lakes and the population appears to be stable. I do not agree that it should be down-listed as Least Concern.
India constitutes one of the largest distributional range for darter. The sighting of darters in India has not been so encouraging for the past few years. Irrespective of the status of this bird in other regions, since there is no perceptible change in the darter population in India over the years, rather speculation of decline based on frequency of sightings, it would not be prudent to downgrade the status at this stage without sufficient data.
I agree with the proposed down-listing, which in my opinion, has been long overdue.
Adding to some of the comments above, I could not find any reference as to why South Asia is NOT the stronghold for this species – the bird is widespread and extending its range and colonizing new sites here. For e.g., it has already reached the Jammu region and Andaman Islands in the last half-decade.
This is probably reflective of the trend of several large waterbirds like Black-headed & Glossy Ibis, Asian Woollyneck, Painted Stork etc where they seem to be doing reasonably well as a group in India and colonising new areas but probably declining elsewhere in its range (SE Asia ?).
For instance, bulk of the population Kerala during 1990s was concentrated in central Kerala (see Sashikumar et al. 2011) but now they occur in all wetlands across the state and breeding even in city wetlands like the zoo in Thiruvananthapuram – which is similar to the situation as reported by S Subramanya above for Karnataka. From pre-1990 levels, there has been a noticeable increase in southern India and probably it may have reached its peak levels.
Notes in the Waterbird Populations Portal http://wpp.wetlands.org/explore/3645/1483 for this species has created two biogeographic populations of this resident species, one for South Asia and Southeast Asia.
It would be useful to get an understanding of the population size for the species, as the WPE4 and WPE5 information is outdated and states 1-10,000 individuals.
The last information of a rough size estimate for the South Asian population is repeated from WPE1-WPE 5, so even in 1987- 1991 it is estimated as 4000.
Numbers reported during the AWC have never exceeded a 1000 birds in a year for this population across Bangladesh, Bhutan, India, Nepal and Sri Lanka in the last years.
The last information of a rough size estimate for the South East Asia population is a collation from 2005 and repeated in WPE5 – referenced as Li in litt. 2005 in the Waterbirds Population Portal:
at least 4,000 in Cambodia, 2,000-2,500 in Myanmar, up to 1,000 in East Malaysia, ‘a few thousand’ in Indonesia.
Also up to 150 in Vietnam, <10 in Laos, up to 100 in Thailand.
It would be useful to assess the current population estimate against this.
As per the latest IWC report for the 2019-2023 period https://iwc.wetlands.org/index.php/spectotals
Cambodia recorded a max of 7368 in 2019, 1988 in 2020, 3589 in 2021 but only 758 in 2022.
Indonesia recorded a max of 153 in 2019, 76 in 2020, 148 in 2021 and 178 in 2022.
Myanmar recorded a max of 263 in 2019 and 165 in 2020, with poor coverage thereafter.
Thailand had 158 in 2019 and 171 in 2020, but none reported since.
So there should be an proper population assessment undertaken for the two populations to understand current status, prior to its down-listing.
Additionally, as a fish eating species dependent largely on shallow wetland habitats and where fishing activities with nets are intensifying within many protected areas and in unprotected areas, the threat of accidental drowning needs to be assessed as a current/future threat to the species, and factored into any assessment of its proposed down-listing.
I do not agree with the comments Oriental Darter being least concerned from Near Threatened category because population has been gradually declining due to decreasing wetland habitats and insufficient food especially in northern, central, western India. It’s good evidence of declining population as being recorded during past few years till 2024 AWC in the protected areas.
In response to comment by Taej Mundkur, I fully agree that a reassessment of South Asia population is needed. Darter is vastly under-counted during the AWC in winter. Population estimation should be done using heronry counts. For e.g. total number of darter nests from the state of Kerala in the year 2016 (best year so far) was 2,000 nests ! Latest is 1500. Details of heronry counts from Kerala has been forwarded to the redlist team by R Roshnath (state heronry count coordinator) – but looks like his update has not been posted by the Redlist team here (I will be reforwarding that email).
We received the following contribution from R Roshnath:
“We recently found out that certain birds’ IUCN status is changing. We wanted to let you know that Kerala, India appears to have a stable number of Oriental Darters nests. Based on our systematic monitoring of Kerala’s heronries, we have come to this conclusion.”
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 12 February 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 12 February 2024, when discussions will re-open.
Many thanks to all those who have taken the time to comment on the forum topic above. It is clear there is legitimate concern from some parts of the range that this species may be declining. However, this assessment is about the species’ global range and global extinction risk, thus in addition to anecdotes of declines from India, these must be counterbalanced with evidence of population recovery and expansion in South-East Asia. Moreover, in parts of India, the population is evidently doing well (stable or increasing). As alluded to by Praveen J above on 05/02/2024, an email received from R. Ramesh containing nest count data from Kerala 2014-2022 shows a fluctuating but broadly stable trend, a pattern that is consistent for this species elsewhere (with numbers in any given year fluctuating depending on water levels and food availability). Moreover, comments made by Praveen J directly on 30/01/2024 suggest that in some parts of India the species has expanded its range. Note also that while V. M. Nagarajan (in litt. above) noted that State of India’s Birds showed a decline, the most recent iteration of this report (SoIB 2023) showed a stable reporting trend; these data have already been incorporated into the assessment written above.
Notwithstanding the comments about local declines above, which have been summarised and incorporated into a revised population trend account, there is no reason to suspect that declines have globally exceed 20% over the past three generations, or are likely to in the next. Accordingly, it does not meet or approach the thresholds for listing as threatened and accordingly our preliminary proposal for the 2024 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 18 February 2024, after which the recommended categorisations will be put forward to IUCN.
The final 2024 Red List categories will be published on the BirdLife and IUCN websites in December 2024, following further checking of information relevant to the assessments by both BirdLife and IUCN.
Adding to previous details, in 2023, we have monitored the birds in the three Ramsar sites of Kerala, every month, as part of the monthly Ramsar site monitoring project by the State Wetland Authority of Kerala (SWAK) from May-Dec. The wetland monitoring follows AWC protocol with 28 counting units. In addition, we also have done nest counts of heronries near the Ramsar sites following the Kerala Heronry Monitoring Protocol from Jun to Oct. Here, the population of breeding Oriental Darters is better monitored than the Asian Waterbird Census method. We found 447 nests of Oriental Darter in the Kole wetlands and 657 nests in the Vembanad wetlands making it more than 1000 breeding pairs only in the Kole-Vembanad Ramsar site. During AWC-type wetland counts, the maximum monthly count of Darters recorded across all three Ramsar sites was only 316 in July 2023.
Niranjana K S
Coordinator for SWAK Ramsar Monitoring Project
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 we will post a final decision on this species’ Red List status on this page on 26 February 2024.
Recommended categorisation to be put forward to IUCN
The final categorisation for this species has not changed. Oriental Darter is recommended to be listed as Least Concern.
Many thanks for everyone who contributed to the 2024.1 GTB Forum process. The final 2024 Red List categories will now be published on the BirdLife and IUCN websites in October 2024, following further checking of information relevant to the assessments by both BirdLife and IUCN.
I don’t agree with the proposed category of least concern. It’s population is still on declining trend. And it should be categorized as near threatened.
I also do not agree with being the least concerned, because the population has gradually been in a declining situation owing to the decline of the wetland habitat as well as their insufficient fish food species in previously potential sites. It was also evident during the 2024 AWC bird count in protected areas.
I do not want to agree with being the least concerned, instead proposed to include the species as near-threatened owing to the drastic decline of the population status in the Northeastern region of India.
I do not agree with this assessment. The bird has been showing decline according to State of India’s Birds report. It should stay as a NT species.
Apart from the country-wide trend (=stable) from India which is already referred to in the text, the same is reflected at a few state levels as well.
Kerala: Stable (Current)
https://stateofindiasbirds.in/species/kl-darter2/
Karnataka: Stable (Current)
https://stateofindiasbirds.in/species/ka-darter2/
Gujarat: Stable (Long-term)
https://stateofindiasbirds.in/species/gj-darter2/
Other states do not have conclusive trends to make a statement.
Downgrading to Least Concerned, instead of keeping or including the species as near-threatened owing, doesn’t make a proper sense given the drastic decline of the population status actoss the Indian SubContinent
This bird is still not a commonly sighted species,given that it’s very habitat specific bird ,and it’s population trends doesn’t require it to be addressed as least concern
I do no know the current status and population of Oriental Darter , but in case of Nepal, it should be considered as Near Threatened as its population is in declining trend.
In Southeast Asia, at least in Cambodia, Oriental Darter has undergone a dramatic population increase, which is evidenced both by annual systematic population monitoring data from the largest colony (at Prek Toal on the Tonle Sap Lake) and just by casual birding records. The species has gone from one that was rarely sighted away from Prek Toal to one that is commonly seen in wetlands across the country. It now breeds at many wetland sites. In the context of population trends in this part of its range (which must constitute most of the world population) it is inconceivable that it is anything other than Least Concern.
We received the following contribution from Fred Goes:
“I looked at the species to review for Asia, and my expertise being about Cambodia, it concerns only WWDuck and ODarter.
Overall I fully agree with your proposed category change, with only one caveat.
For ODarter, there has been no available data since 2013 on the trend and population for the Prek Toal colony, Tonle Sap, which is the species stronghold in SEAsia ! At the time, the colony was fluctuating yearly between 5,000-7,000 pairs (2008-2012, WCS data in Goes 2014).
I hope that my former WCS colleagues can provide more recent pop data, as well as information on eventual spill-over colonies around the Tonle Sap or further away in Cambodia.”
Dont think this can be pushed to LC, the bird status is going on a downward trend and is not seen often like it was seen earlier.
About 30 water bodies surveyed around keoladeo national Park in Rajasthan between 2004-2007. Except few sites all had no presence of Oriental darter. In keoladeo national Park, one of largest heronry in Asia they are also declining trend. It is therefore considered at least near threatened.
Prior to 1994, the species was uncommon in Bangalore with only three sight records over a decade. However, the situation changed from mid 1990 onwards when the lakes of Bangalore were leased out for commercial fishing and the lakes were seeded with fish species like Rohu (Labeo rohita), Catla (Catla catla)and Tilapia (Oreochromis sp.). Today the species is seen small numbers in lakes of Bangalore and also breeds at several lakes and the population appears to be stable. I do not agree that it should be down-listed as Least Concern.
India constitutes one of the largest distributional range for darter. The sighting of darters in India has not been so encouraging for the past few years. Irrespective of the status of this bird in other regions, since there is no perceptible change in the darter population in India over the years, rather speculation of decline based on frequency of sightings, it would not be prudent to downgrade the status at this stage without sufficient data.
I agree with the proposed down-listing, which in my opinion, has been long overdue.
Adding to some of the comments above, I could not find any reference as to why South Asia is NOT the stronghold for this species – the bird is widespread and extending its range and colonizing new sites here. For e.g., it has already reached the Jammu region and Andaman Islands in the last half-decade.
This is probably reflective of the trend of several large waterbirds like Black-headed & Glossy Ibis, Asian Woollyneck, Painted Stork etc where they seem to be doing reasonably well as a group in India and colonising new areas but probably declining elsewhere in its range (SE Asia ?).
For instance, bulk of the population Kerala during 1990s was concentrated in central Kerala (see Sashikumar et al. 2011) but now they occur in all wetlands across the state and breeding even in city wetlands like the zoo in Thiruvananthapuram – which is similar to the situation as reported by S Subramanya above for Karnataka. From pre-1990 levels, there has been a noticeable increase in southern India and probably it may have reached its peak levels.
Notes in the Waterbird Populations Portal http://wpp.wetlands.org/explore/3645/1483 for this species has created two biogeographic populations of this resident species, one for South Asia and Southeast Asia.
It would be useful to get an understanding of the population size for the species, as the WPE4 and WPE5 information is outdated and states 1-10,000 individuals.
The last information of a rough size estimate for the South Asian population is repeated from WPE1-WPE 5, so even in 1987- 1991 it is estimated as 4000.
Numbers reported during the AWC have never exceeded a 1000 birds in a year for this population across Bangladesh, Bhutan, India, Nepal and Sri Lanka in the last years.
The last information of a rough size estimate for the South East Asia population is a collation from 2005 and repeated in WPE5 – referenced as Li in litt. 2005 in the Waterbirds Population Portal:
at least 4,000 in Cambodia, 2,000-2,500 in Myanmar, up to 1,000 in East Malaysia, ‘a few thousand’ in Indonesia.
Also up to 150 in Vietnam, <10 in Laos, up to 100 in Thailand.
It would be useful to assess the current population estimate against this.
As per the latest IWC report for the 2019-2023 period https://iwc.wetlands.org/index.php/spectotals
Cambodia recorded a max of 7368 in 2019, 1988 in 2020, 3589 in 2021 but only 758 in 2022.
Indonesia recorded a max of 153 in 2019, 76 in 2020, 148 in 2021 and 178 in 2022.
Myanmar recorded a max of 263 in 2019 and 165 in 2020, with poor coverage thereafter.
Thailand had 158 in 2019 and 171 in 2020, but none reported since.
So there should be an proper population assessment undertaken for the two populations to understand current status, prior to its down-listing.
Additionally, as a fish eating species dependent largely on shallow wetland habitats and where fishing activities with nets are intensifying within many protected areas and in unprotected areas, the threat of accidental drowning needs to be assessed as a current/future threat to the species, and factored into any assessment of its proposed down-listing.
I do not agree with the comments Oriental Darter being least concerned from Near Threatened category because population has been gradually declining due to decreasing wetland habitats and insufficient food especially in northern, central, western India. It’s good evidence of declining population as being recorded during past few years till 2024 AWC in the protected areas.
In response to comment by Taej Mundkur, I fully agree that a reassessment of South Asia population is needed. Darter is vastly under-counted during the AWC in winter. Population estimation should be done using heronry counts. For e.g. total number of darter nests from the state of Kerala in the year 2016 (best year so far) was 2,000 nests ! Latest is 1500. Details of heronry counts from Kerala has been forwarded to the redlist team by R Roshnath (state heronry count coordinator) – but looks like his update has not been posted by the Redlist team here (I will be reforwarding that email).
We received the following contribution from R Roshnath:
“We recently found out that certain birds’ IUCN status is changing. We wanted to let you know that Kerala, India appears to have a stable number of Oriental Darters nests. Based on our systematic monitoring of Kerala’s heronries, we have come to this conclusion.”
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 12 February 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 12 February 2024, when discussions will re-open.
Preliminary proposal
Many thanks to all those who have taken the time to comment on the forum topic above. It is clear there is legitimate concern from some parts of the range that this species may be declining. However, this assessment is about the species’ global range and global extinction risk, thus in addition to anecdotes of declines from India, these must be counterbalanced with evidence of population recovery and expansion in South-East Asia. Moreover, in parts of India, the population is evidently doing well (stable or increasing). As alluded to by Praveen J above on 05/02/2024, an email received from R. Ramesh containing nest count data from Kerala 2014-2022 shows a fluctuating but broadly stable trend, a pattern that is consistent for this species elsewhere (with numbers in any given year fluctuating depending on water levels and food availability). Moreover, comments made by Praveen J directly on 30/01/2024 suggest that in some parts of India the species has expanded its range. Note also that while V. M. Nagarajan (in litt. above) noted that State of India’s Birds showed a decline, the most recent iteration of this report (SoIB 2023) showed a stable reporting trend; these data have already been incorporated into the assessment written above.
Notwithstanding the comments about local declines above, which have been summarised and incorporated into a revised population trend account, there is no reason to suspect that declines have globally exceed 20% over the past three generations, or are likely to in the next. Accordingly, it does not meet or approach the thresholds for listing as threatened and accordingly our preliminary proposal for the 2024 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 18 February 2024, after which the recommended categorisations will be put forward to IUCN.
The final 2024 Red List categories will be published on the BirdLife and IUCN websites in December 2024, following further checking of information relevant to the assessments by both BirdLife and IUCN.
Adding to previous details, in 2023, we have monitored the birds in the three Ramsar sites of Kerala, every month, as part of the monthly Ramsar site monitoring project by the State Wetland Authority of Kerala (SWAK) from May-Dec. The wetland monitoring follows AWC protocol with 28 counting units. In addition, we also have done nest counts of heronries near the Ramsar sites following the Kerala Heronry Monitoring Protocol from Jun to Oct. Here, the population of breeding Oriental Darters is better monitored than the Asian Waterbird Census method. We found 447 nests of Oriental Darter in the Kole wetlands and 657 nests in the Vembanad wetlands making it more than 1000 breeding pairs only in the Kole-Vembanad Ramsar site. During AWC-type wetland counts, the maximum monthly count of Darters recorded across all three Ramsar sites was only 316 in July 2023.
Niranjana K S
Coordinator for SWAK Ramsar Monitoring Project
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 we will post a final decision on this species’ Red List status on this page on 26 February 2024.
Recommended categorisation to be put forward to IUCN
The final categorisation for this species has not changed. Oriental Darter is recommended to be listed as Least Concern.
Many thanks for everyone who contributed to the 2024.1 GTB Forum process. The final 2024 Red List categories will now be published on the BirdLife and IUCN websites in October 2024, following further checking of information relevant to the assessments by both BirdLife and IUCN.