Data Zone
Justification of Red List category
This species has a large range that spans much of South and South-East Asia, where in recent years it has been increasing in abundance in line with increasing protection of wetlands. Although its population size is unknown, it is thought likely to be very large given the pattern of records in its large range. It is therefore evaluated as Least Concern.
Population justification
The global population size of this species has not been formally evaluated, but consideration of the size and number of colonies throughout South Asia and South-East Asia (e.g. Goes 2013, Visal and Mahood 2015, Haq et al. 2018, eBird 2024) suggests that the population probably numbers at least in the tens of thousands.
Trend justification
Although Oriental Darter may locally be declining, the global population is now very probably stable or slightly increasing. Formerly, this species was suspected to be declining moderately rapidly, principally in response to pollution, wetland drainage and, especially in South-East Asia, hunting (BirdLife International 2001). More recently, successful conservation action in parts of its range have reversed this trend and the species has probably been increasing in abundance since the turn of the century. In India, eBird citizen science data suggest a stable reporting rate (SoIB 2023), while heronry count data from Kerala 2014-2022 show a fluctuating but broadly stable trend (R. Ramesh in litt. 2024). The species has also expanded its range in Kerala, and has only recently colonised Jammu and the Andaman Islands (Praveen J in litt. 2024). While there are reports of localised declines (A. Verma and S. Subramanya in litt. 2024), these are probably offset by recoveries elsewhere.
At the Tonle Sap waterbird colony in Cambodia, the population has recovered from historic persecution, with 241 nests in 2000 increasing to several thousand (Goes 2013). In large part, this contributed to recoveries elsewhere in South-East Asia. In Thailand, the species was nearly extinct by the mid-1980s (the species only persisting in a few remote forested rivers: P. D. Round in litt. 2023) but recovered rapidly concurrently with populations in Cambodia, and the species is now widespread and common throughout most of the country (P. D. Round in litt. 2023, eBird 2024; see also data in Haq et al. (2018) and testimony in Round (2008)). Observations in Peninsular Malaysia and Singapore have also recently been increasing (with a notable increase from 2016) and the first modern breeding of the species in Peninsular Malaysia was recorded in 2022 (Amar-Singh HSS et al. 2023). The species has so far not been successful in returning to Lao PDR as a breeding visitor, despite formerly having almost certainly been so, due to ongoing threats (principally hunting). However its extirpation here as a breeding species was historical and there are signs of increasing non-breeding numbers (Timmins et al. 2024). There are no time series data from Indonesia, although where it would be expected the species continues to be seen in good numbers (eBird 2024).
Overall, the species is suspected of having increased its population size in the past three generations (22 years: 2002-2024) and this trend is likely to continue with increasing protection of wetlands throughout its range.
This species has a wide distribution across the Oriental region, occurring (perhaps recently only marginally) in Pakistan, India (widespread resident), Nepal, Sri Lanka, Bangladesh, Myanmar, Thailand, Lao PDR, Viet Nam, Cambodia, Peninsular Malaysia, Malaysian Borneo, Singapore, Brunei, Indonesia (Sumatra, Java, Sulawesi, Kalimantan).
It inhabits shallow inland wetlands including lakes, rivers, swamps and reservoirs.
In common with many other Asian waterbirds, it is primarily threatened by habitat loss (both degradation of foraging areas and felling of trees used for breeding), pollution, disturbance (at feeding grounds and colonies), hunting, egg collecting and pollution. These threats historically were likely driving global declines (BirdLife International 2001), however more recently the population is known to have expanded and be increasing, thus these threats are evidently not operating at a scale or acuity capable of driving global population declines.
Conservation Actions Underway
It occurs in a number of protected areas across its range. At Prek Toal on the Tonle Sap Lake, Cambodia, WCS initiated a scheme in 2002 that employed former egg collectors as colony guards. Together with MoE staff, they protect and monitor the colony throughout the nesting period from tree top platforms and numbers have increased from 241 nests in 2002 to several thousand nests now.
Text account compilers
Berryman, A.
Contributors
Mahood, S., van Eijk, P., Jayadevan, P., Ramesh, R., Subramanya, S., Verma, A. & Round, P.
Recommended citation
BirdLife International (2024) Species factsheet: Oriental Darter Anhinga melanogaster. Downloaded from
https://datazone.birdlife.org/species/factsheet/oriental-darter-anhinga-melanogaster on 30/12/2024.
Recommended citation for factsheets for more than one species: BirdLife International (2024) IUCN Red List for birds. Downloaded from
https://datazone.birdlife.org/species/search on 30/12/2024.