Archived 2012-2013 topics: Great Thick-knee (Esacus recurvirostris): uplist to Near Threatened or Vulnerable?

BirdLife species factsheet for Great Thick-knee Great Thick-knee Esacus recurvirostris is located from SE Iran through the Indian Subcontinent and Sri Lanka to Indochina and Hainan (S China). It is currently listed as being of Least Concern, on the basis that it was not thought to approach the thresholds for Vulnerable under any of the IUCN criteria. However, Thewlis et al. (1998) noted that the species had declined greatly in Laos, noting that there were very few records despite extensive searches of suitable habitat along the Mekong (Thewlis et al. 1998), whereas it was noted to be a common resident along the Mekong in Savannakhet Province during the mid-20th century (David-Beaulieu 1949-1950 in Thewlis et al. 1998). Eggs of the species are collected by local people in the Ban Hangkhon area of Laos (Boonhong Mounsouphon and I. Baird verbally 1995 in Thewlis et al. 1998) and predation by dogs has been recorded (Thewlis et al. 1998). Furthermore, Rasmussen and Anderton (2012) describe the species as widespread but now very local in South Asia. Species occupying similar habitats and with a similar range to this species, such as River Lapwing Vanellus duvaucelii, River Tern Sterna aurantia and Black-bellied Tern Sterna acuticauda, have recently been uplisted under the A criterion of the IUCN Red List (to Near Threatened, Near Threatened and Endangered respectively), owing to similar pressures. At least in south-east Asia, Great Thick-knee has been described as between these species of tern and River Lapwing in its trajectory towards regional extinction (W. Duckworth in litt. 2012). It is possible that over the past three generations (32 years, based on an estimated generation length of 10.5 years) this species has experienced a moderately rapid (approaching 30%) or rapid (30-49%) population decline, which is likely to continue into the future. The species could therefore warrant uplisting to Near Threatened (approaching 30% over three generations) or Vulnerable (30-49% decline) under criterion A2cd+3cd+4cd. If moderately rapid declines are not yet suspected to be taking place, but future threats such as dam development and increasing human pressures, such as direct exploitation, disturbance and predation by animals associated with humans, are predicted to cause declines to become moderately rapid or rapid over the next three generations, this species would warrant uplisting to Near Threatened (approaching 30% over three generations) or Vulnerable (30-49% decline) under criterion A3cd. Further information is requested on this species’s population trends and size. Comments on the severity of threats to this species are also welcome. References: Rasmussen, P. C. and Anderton, J. C. (2012) Birds of South Asia. The Ripley Guide. Volume 2: Attributes and Status. Second Edition. National Museum of Natural History – Smithsonian Institution, Michigan State University and Lynx Edicions, Washington, D. C., Michigan and Barcelona. Thewlis, R. M. Timmins, R. J., Evans, T. D. and Duckworth, W. (1998) The conservation status of birds in Laos: a review of key species. Bird Conservation International 8 (Supplement): 1-159.

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12 Responses to Archived 2012-2013 topics: Great Thick-knee (Esacus recurvirostris): uplist to Near Threatened or Vulnerable?

  1. Sathyanarayana Srinivasan says:

    On 26/11/2012 I saw two birds along Godavari river near Devipatnam, East Godavari district, Andhra Pradesh. This was a one-off visit, so I do not have information regarding the status of the bird in this area.
    The river here has large sandbanks flanked by forested hills. Fields are confined to the narrow strip of land between the river and hills. Some portion of this area falls under Papikonda National Park, though I am not aware of the exact boundaries.
    Distant pix of the birds are at
    Also, what I found interesting about this place is that I saw the two other birds at risk mentioned above – the River Lapwing(3 birds) and a pair of Black-bellied Terns
    The upper course of the Godavari river, where it flows through thinly(relative to the delta) populated areas appears to be under-visited by amateur birdwatchers; this is an area that needs urgent attention as it falls under the submergence zone of the Polavaram dam when it is completed

  2. Sathyanarayana Srinivasan says:

    Map of sighting location along with pix are here

  3. I recently (March 2013) sighted the Great Thick-knee at Ranganathittu bird sanctuary, Karnataka, India. There were four birds in total. In the past, I have sighted this species in small numbers (2-4) on all but two of my visits to Ranganathittu, in the months of March, April, August and October.

  4. The situation in Lao PDR has got considerably worse since the last 1990s (and in fact was then somewhat better – just a little – than Thewlis et al. had thought). Post-Thewlis evidence suggested a large population in the Mekong between Vientiane and Louangphabang, where birds were seen almost every day trip to almost anywhere in the stretch with suitable habitat (about a third of the whole stretch). Yet an intensive survey in 2011-2012 (fielding in total about 5-8x as much search effort as in 1997-2004) failed to see or hear any birds (3 weeks of camping almost every night in prime river channel habitat and specifically listening) although a handful of footprints found probably came from thick-knees (could also be Northern Thick-knee). No other Lao area has had meaningful resurvey in the last decade+. Thus although the species was already hugely declined 20 years ago (and in fact the major losses in Lao probably occurred before the 32-year window for past decline started, i.e. 1983), there have surely (as much as can be stated on fragmentary information) been steep ongoing declines there. National-level extinction seems inevitable on current patterns. With such a large range one needs to be cautious in inferring too much from one small country; information from Cambodia and Myanmar is vital to understanding the SE Asia picture.

  5. Paul Thompson says:

    In Bangladesh there are very few records. Appart from sightings in one area near the Sundarbans and coastline; along the main rivers there are hardly any sightings in the last 20 years. I have one sighting from the Jamuna in the mid 1990s, and recent searches for terns on the main rivers have not as far as I know revealed any birds (nor terns). Yet there are large areas of seasonal sandbanks along the main rivers. While this does not show a recent decline, it does confirm its rarity and it had already declined/disappeared 20+ years ago from areas that would apear suitable.

  6. Praveen J says:

    In South India, the bird appears to be partial to larger rivers and shows high site fidelity (e.g. Ranganathittu birds). Like Black-bellied Tern, threats are similar in nature with its ideal habitat are potentially converted. However, the bird is also seen in stagnant water, not necessarily flowing rivers (e.g. TG Halli in Bangalore, Ranganathittu) – so creation of check dams on rivers may not be a direct threat. There is some incidence of vagrancy, away from its regular haunts (e.g. Rajeevan 2011 in Kerala) – but these are far & few between. There is not much historical information to compare against, but it is expected that a decline in its population – similar to Black-bellied Tern – should have happened. It appears to be Near-threatened (30%) if not Vulnerable.

  7. Andrea Claassen says:

    In Cambodia, Great Thick-knee is still fairly common on the Mekong River between Kratie and Stung Treng. However, in 2007 Rob Timmins estimated about 70 individuals in this stretch (Bezuijen et al. 2008–WWF survey of Mekong River), and my counts from 2010-2013 for the same stretch suggest about half to two-thirds of Timmins estimate.

    From 2009-2013 I located and monitored 8 nests of Great Thick-knee on the Mekong River. Apparent (raw) nest success was 50%; 4 successfully hatched and 4 failed from predation (3 from rats, 1 likely from crow). Note: humans often take eggs, but all Great Thick-knee nests in this study were being protected by local people. Unfortunately the local guards were not effective in preventing animal predation.

    Great Thick-knee has nearly disappeared from Mekong tributaries (Sesan and Sekong Rivers) in northeastern Cambodia. On the Sesan River I counted 5-9 birds in 2003, 2 in 2009, and zero in 2013. On the Sekong River I had 2 birds in 2003 between Siempang and Stung Treng, but did not survey upstream of Siempang. In 2013 I had zero between Siempang and Stung Treng, but I did have 4 on the upstream stretch between Siempang and the Lao border.

    In Cambodia it appears that there has been a small to moderate population decline over the last 10 years. Based on what I have seen here I am inclined to say it should be uplisted to Near-threatened. However, the species has a very large global range and I would like to know what researchers in other parts of its range are finding. Anecdotal one-time sightings are of limited value. Has anyone done any consistent surveys elsewhere in its range?

  8. Craig Robson says:

    I think that Great Thick-knee is on its ‘last legs’ in South-east Asia (apart from Myanmar). Information from Myanmar is sadly lacking, and it would be great if someone could carry out some systematic riverine bird surveys there. The first time I went to Bagan, in 1995, we saw this species easily, along with Indian Skimmer, and Black-bellied and River Terns. All these species have gone from its vicinity now. Too many people, boats and disturbance. But Myanmar is a big country, with potentially huge tracts of suitable remaining habitat. India, and perhaps other countries in the subcontinent, are pretty much the only real hope for this species as we see things right now. It should be considered at least Near Threatened in the Indian subcontinent and Myanmar as a whole, but Critically Endangered in Thailand and Indochina.

  9. R. J. Timmins says:

    Not much to add. The decline in Cambodia is more recent than that in Laos, and from what I hear (no perseonal experience) Myanmar is following a similar economic and development trajectory suggesting the same fate awaits the species there. Cambodian population decline would certainly trigger VU and probably EN (especially considering most surveys have been in the heart of the species cambodian range – and more significant declines would be expected in peripheral range areas). The listing depends significantly on the state of the Indian subcontinent population.

  10. Richard Porter says:

    Nothing to add as I know little about this species. For information I have counts for the the Iranian Baluchistan coast (1972), Kosi River (1981) and Modhva coast on n side of Gulf of Kutch (2012).

  11. Frederic Goes says:

    Craig, Rob and Will have adequately summarized the situation of the species in SEAsia. I totally support their views that it is regionally (Myanmar excluded) highly threatened. From my experience and record collation from Cambodia, I am inclined to be more pessimistic than Andrea. Below is the summary account and conservation discussion (excerpt from the checklist in press). Detailed listing of records available on request.

    Great thick-knee
    A rare resident associated with riverine sandbars, islands and scrub, where it breeds during the dry season. Restricted to the upper Mekong channel and its tributaries from November to May. Whereabouts during the flood months largely unknown, apart from an historical record at Kampot estuary and a recent sighting in rice fields near Takeo // Conservation: In Cambodia, the only viable population subsists in the upper Cambodian Mekong, with the Sesan and Sekong supporting perilously low numbers. Timmins (2008) considered the whole Mekong population to range in the low hundreds of pairs. However, a riverine-nesting bird study in the central Kratie – Stung Treng Mekong estimated less than 100 individuals in 2010–2012, suggesting a population decline (AC). Ubiquitous threats of nest predation by dogs, disturbance by fishermen and domestic animals, and opportunistic harvesting has caused chronically low breeding success of riverine nesting birds throughout the region (Timmins & Men 1998, Claassen 2004). On the Sesan, marked declines were not detected between 1998 and 2003 (Claassen 2004), but a survey covering most of the river length in January–February 2010 found only one bird (AC, FG). This recent precipitous decline is probably due to upstream Vietnamese dams (sudden water level rises inundating nests), and imminent extinction there seems unavoidable. The fate of the small Sekong population does not seem more promising, even if appropriate conservation actions are implemented, as 19 dams are planned on this river (Kummu et al. 2010). The current status of the population at the Ramsar Mekong is unknown, but likely in decline as well. There is urgent need for nest-protection programmes and monitoring of human activities during the dry season. If planned hydro-power dams on the main Mekong channel in southern Laos, at Stung Treng and Sambor (Kratie) are built (Barlow et al. 2008), the species’ future looks bleak. Major alteration of flood regimes and the river ecology could arguably lead to extinction in the medium term. Owing to a very small population, recent decline and human and habitat-related threats the species faces, it qualifies as Critical in Cambodia.

    Great Thick-knee has been assessed as Critically Endangered in Nepal based on the criteria A2cde and C2a(i) in a draft species account prepared for the Nepal bird Red Data Book. This draft assessment was upheld at the October 2012 workshop held to discuss over 240 draft Nepal species accounts. The following text is extracted from the full Great Thick-knee species account which is available for download from the front page of Himalayan Nature: A distribution map showing pre- and post-1990 distribution is also available here.

    STATUS AND POPULATION The species is now rare. Its population has declined and the number of localities has reduced. The Great Thick-knee population is now extremely small and appears to be almost entirely restricted to one locality. Most recent records are from the Koshi Barrage area, an unprotected site, although there are also a very few post-1990 records from Koshi Tappu Wildlife Reserve and Chitwan and Bardia National Parks. The population may now be as few as 10 individuals.

    THREATS The species is seriously threatened by disturbance and the degradation and loss of its riverine habitat.

    Carol Inskipp and Hem Sagar Baral

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