Archived 2017 topics: A review of the status of endemic/near-endemic birds of the Andaman Islands currently listed as Near Threatened

Background to this topic

The Andaman Islands are a group of islands in the Bay of Bengal in the Indian Ocean. The main vegetation type on the islands is tropical evergreen forest, with some grasslands in inland regions and mangroves on the coastlines (Islam and Rahmani 2004). With an expanding human population on the islands, there is increasing pressure on the natural habitats there. Forest is being lost as a result of this, as residential areas, tourist developments, agriculture, grazing and logging spread, with knock on consequences for the species that inhabit these forests (e.g. see Islam and Rahmani 2004). Additionally, coastal areas face erosion due to sand mining and birds may be hunted on the islands, which could be affecting some species (e.g. Andaman Woodpigeon, Columba palumboides, and Andaman Cuckoo-dove, Macropygia rufipennis) (Islam and Rahmani 2004, BirdLife International 2017).

Combined with these threats, the fact that the Andaman Islands cover only a small area has led to most of the endemic, or near-endemic avifauna being listed as at least Near Threatened. The main criteria that have been used for the species listed as Near Threatened in this region are criteria B1 and C1 (e.g. Andaman Woodpigeon is currently listed under criteria B1ab(ii,iii);C1 [BirdLife International 2017]). However, after a period of review the use of these criteria for these species is unlikely to be appropriate.

In the case of criterion B its use has probably been a result of an incorrect assessment of the number of locations*. Following the IUCN guidelines for defining a location, it is likely that these species are found at far more than 10 locations, and their habitat is as yet not severely fragmented. Therefore, these species would not warrant listing under criterion B, because they would not approach the threshold for Vulnerable under this criterion.

For a species to meet the threshold for Vulnerable under criterion C1, it must have a population of fewer than 10,000 mature individuals and be undergoing a continuing decline of >10% over 3 generations or 10 years (whichever is longer) (IUCN 2012). This does, however, require a high level of confidence in the rate of decline – be it predicted, estimated or observed. To the best of our knowledge there has been no clear assessment of rates of decline in the avifauna of the Andaman Islands and so we cannot assess whether these species meet, or approach, the threshold for Vulnerable under this criterion. Therefore, a reassessment of the Andaman endemic/near-endemic species listed as Near Threatened is required.

This topic conducts this reassessment, but it only covers those Near Threatened endemic or near-endemic species found on the Andaman Islands. It does not look at Least Concern (Andaman Coucal, Andaman Nightjar and White-headed Starling) or threatened species (Narcondam Hornbill, Andaman Teal) of the islands, and also does not look at the endemic/near-endemic species of the nearby Nicobar Islands, although some species discussed in this topic do occur there.

 

Individual Species Accounts

Andaman Serpent-eagle (Spilornis elgini)

This species occurs in the rainforests of the interior of the Andaman Islands, and has been considered the most common raptor there (Clark et al. 2017). Surveys from 1992-1994 found 62 individuals on 25 out of 45 surveyed islands, in a total area of 3,700km2 (Davidar et al. 1996, P. Davidar in litt. 2016). Therefore, this could suggest that there are no more than 1 or 2 individuals per km2 (P. Davidar in litt. 2016). The population is currently placed in the range 1,000-5,000 mature individuals, and P. Davidar in litt. (2016) suggested that the population could be less than 4,000 mature individuals. This may be assuming that the population is evenly spread across its range, whereas it is rarer in more marginal habitats (P. Davidar in litt. 2016). Given the population density estimate of 1-2 individuals per km2 and assuming only a proportion of its range is occupied, the maximum number of mature individuals in the largest subpopulation would only just go above 1,000 mature individuals, and the total population size is more likely to be at the lower end of the current 1,000-5,000 mature individuals estimate. Therefore, it is tentatively suggested that the population size be altered to 1,000-4,000 mature individuals, given the paucity of more targeted data for this species. The largest subpopulation is also conservatively estimated to contain <1,000 mature individuals. Therefore, given how forest loss is likely leading to a population decline and this species may also suffer from hunting, it is proposed that this species be listed as Vulnerable under criterion C2a(i).

Andaman Scops-owl (Otus balli)

This species is capable of tolerating habitat degradation, occurring in even semi-open or cultivated areas, and even around human settlements. It has been described as not uncommon (König et al. 1999) and remains relatively easily found. Therefore, it is unlikely to approach the threshold for Vulnerable under any criterion, and so warrants listing as Least Concern.

Andaman Boobook (Ninox affinis)

This species is thought to mainly occur in lowland forest, though has been reported to occur in secondary forest (König and Weick 2008), as well as mangroves, around human settlements, rubber plantations, and forest clearings. The population size has not been directly estimated, but based on reported home range sizes of the Morepork, N. novaeseelandiae, in New Zealand (3.5-307 ha [Imboden 1975, Pryde and Green 2016]) and Southern Boobook, N. boobook, in Australia (18-206 ha [Olsen et al. 2011]) and assuming that only a proportion of its range is occupied, then the population size of this species may fall in the range of 2,500-9,999 mature individuals. Records for this species come from several islands (for instance see eBird 2017), yet these appear to be very close together, and so the population could potentially be considered to occur in one subpopulation. This is very important because if we were instead to consider the species as occurring in multiple subpopulations it would not approach the threshold for Vulnerable under criterion C2 (>>1,000 mature individuals in the largest subpopulation and not all individuals in one subpopulation) or any other criterion. Therefore, it would warrant listing as Least Concern. If we were to consider the species to only occur in one subpopulation then it would likely warrant listing as Vulnerable under criterion C2a(ii), though its rate of decline would likely be slow due to its ability to tolerate some habitat degradation. We therefore have a particular request for information for this species to better elucidate its population structure.

Andaman Crake (Rallina canningi)

This species favours areas of dense vegetation including tangled thickets in marshes and along streams within or at the edge of forest, and occasionally mangroves. It faces relatively high trapping pressure in addition to habitat loss, and introduced predators may be an extra threat. It is known from North, Middle and South Andaman, but its range is likely greater than currently mapped, with reports from several other islands, including Little Andaman and Havelock (see Pande et al. 2007, eBird 2017). Andaman Crake was formerly considered very common based on high trapping rates of this species, but there were limited recent records until surveys in 2004 found it to be fairly common in suitable habitat (Ezhilarasi and Vijayan 2008). Its population has been estimated at 10,000-25,000 individuals, which roughly equates to 6,700-17,000 mature individuals. The fact that this species likely occurs in more than one subpopulation, with the largest subpopulation probably containing >>1,000 mature individuals, means that Andaman Crake is unlikely to approach the threshold for Vulnerable under any criterion. Therefore, it is proposed that this species be listed as Least Concern.

Andaman Woodpecker (Dryocopus hodgei)

This species is mainly found in the lowlands of the Andamans, inhabiting evergreen and semi-evergreen forest, often in open areas (Winkler and Christie 2017). It has been considered common (Winkler and Christie 2017), and it remains well reported on eBird (eBird 2017); but considering its small range a tentative population estimate of potentially fewer than 1,000 mature individuals has been suggested (P. Davidar in litt. 2016). Given it does appear to continue to be well reported it is proposed that a population size estimate in the range of 1,000-2,500 mature individuals may be most appropriate, with <1,000 mature individuals in the largest subpopulation. Therefore, given that habitat loss may be causing the population to decline, this species would warrant listing as Vulnerable under criterion C2a(i).

Andaman Woodpigeon (Columba palumboides)

This species inhabits dense broadleaved evergreen forest in the Andaman and Nicobar Islands, occurring in small groups or pairs (BirdLife International 2001, Gibbs et al. 2001). Surveys of the Andamans have found this species to be relatively rare (Davidar et al. 1996, Pande et al. 2007), but it does remain well reported on eBird (see eBird 2017). An assessment based on low reported population densities of congeners, and assuming only a proportion of its range is occupied gives a population size estimate in the range of 2,500-9,999 mature individuals, with the largest subpopulation likely containing >1,000 mature individuals. The population is likely declining both as a consequence of habitat loss and hunting pressure, and so it is tentatively proposed that this species remain listed as Near Threatened but now under criterion C2a(i).

Andaman Cuckoo-dove (Macropygia rufipennis)

This species not only occurs on the Andaman Islands, but also the Nicobar Islands. It can tolerate habitat degradation, occurring in secondary growth, gardens and clearings (Gibbs et al. 2001), and while hunting may have an impact on this species, this has not been investigated yet. Its population size has not been quantified, but it has been described as ‘not uncommon’ (Baptista et al. 2017). Therefore, while it is possible that hunting may be having an impact on this species it is highly unlikely that it would approach the threshold for Vulnerable under criterion C2a(i) – a population undergoing a continuing decline, which has a global population size of <10,000 mature individuals, with <1,000 mature individuals in the largest subpopulation. Therefore, it is proposed that this species be listed as Least Concern.

Andaman Green-pigeon (Treron chloropterus)

This species is currently listed as Near Threatened under criterion C2a(i). There are no known published population estimates for this species, but the total population is tentatively considered to be less than 10,000 mature individuals, placed in the range 2,500-9,999 mature individuals. The species occurs in several small subpopulations across the Andaman and Nicobar Islands, with the largest subpopulation potentially containing >1,000 mature individuals. Dependent on forest, the species is inferred to be declining as a result of habitat loss that is occurring across the islands; and the species may be suffering as a result of hunting too (Gibbs et al. 2001). Therefore, it is proposed that this species be retained as Near Threatened under criterion C2a(i).

Andaman Treepie (Dendrocitta bayleii)

This species is restricted to larger islands (>10km2) in the archipelago, though has been occasionally recorded on smaller islands close to larger ones (P. Davidar in litt. 2016). Surveys in 1992-1994 (Davidar et al. 1996) and 2007 (Pande et al. 2007) only found limited numbers of individuals, and it has been suggested that there could be fewer than 500 mature individuals remaining (P. Davidar in litt. 2016). However, it is well documented on eBird (eBird 2017), though this could represent a high amount of survey activity in the area rather than a true reasonably great abundance. As such, it is tentatively suggested that the population size be placed in the range of 250-999 mature individuals. The species likely occurs in more than one subpopulation, but the largest (on South Andaman & North and Middle Andaman) likely contains the majority of these individuals. Therefore, it is proposed that this species be listed as Vulnerable under criteria C2a(i);D1.

Andaman Drongo (Dicrurus andamanensis)

This species occupies evergreen and broadleaf forest in the lowlands of the Andaman Islands (with some eBird reports from Nicobar Islands [eBird 2017]), though it can also be found at forest edges and in jungle just inside coconut plantations (Rocamora and Yeatman-Berthelot 2017). The population size of this species has not been estimated, but it has been described as ‘reasonably numerous’ (Rocamora and Yeatman-Berthelot 2017), and given its distribution it is likely made up of more than one subpopulation. Therefore, while it is possible that its population is in decline as a result of habitat loss and degradation, it is unlikely to approach the threshold for Vulnerable under criterion C2a(i) (a population undergoing a continuing decline, which has a global population size of <10,000 mature individuals, with <1,000 mature individuals in the largest subpopulation). Therefore, it is proposed that this species be listed as Least Concern.

Andaman Cuckoo-shrike (Coracina dobsoni)

This species was recently split from C. striata. It is found in the southern Andaman Islands, being present on South Andaman (Rasmussen & Anderton 2012), Little Andaman and Havelock Island, with its presence on the North and Middle Andamans being uncertain (P. Jayadevan in litt. 2016). It keeps largely to tall trees (Rasmussen and Anderton 2012) and so forest loss and degradation is likely causing this species to decline. Based on an assessment of population density estimates of congeners, and assuming that only a proportion of its range is occupied would place the population of this species in the range of 10,000-19,999 individuals, which would roughly equate to 6,667-13,333 mature individuals. Its presence on separate islands, particularly Little Andaman, suggests that there could be more than one subpopulation, and so even though the species may be declining it would not approach the threshold for Vulnerable under criterion C2a – all individuals are not in one subpopulation, and there are likely more than 1,000 mature individuals in the largest subpopulation. Therefore, the species likely warrants listing as Least Concern.

Andaman Bulbul (Brachypodius fuscoflavescens)

This species was until recently placed in the genus Pycnonotus and lumped with B. atriceps as P. atriceps by BirdLife. It inhabits a range of forested habitats, including evergreen forest, light deciduous forest, forest edge and thick secondary growth (Fishpool and Tobias 2017). Its population status has been variously reported as abundant through to rare, although it may be locally common in certain areas such as Mount Harriet National Park (Fishpool and Tobias 2017). Tentatively using low population density estimates of its former congeners, and assuming only a proportion of its range is occupied would give an approximate population size estimate of c.8,000 mature individuals, but with >>1,000 mature individuals in the largest subpopulation. Therefore, even though habitat loss may be causing this species to decline, it is unlikely to approach the threshold for listing as Vulnerable under any criterion and hence it is proposed that it be listed as Least Concern.

Andaman Shama (Kittacincla albiventris)

This species was recently split from K. malabarica (formerly in the genus Copsychus). It may occupy a range of lowland forest habitats (see Collar 2016), and it may be to be able to tolerate some habitat disturbance, because the pre-split species could be found in habitats such as secondary forest and overgrown plantations (Collar 2016). As such, forest conversion and loss may not be having a concomitant impact upon this species’s population, and so the population trend may be considered stable. The population size of this species has not been estimated, but the pre-split species was considered common throughout its range (see Collar 2016), and so it may be considered to not approach the threshold for Vulnerable under any criterion. Therefore, it is proposed that this species be listed as Least Concern.

 

We welcome any comments or information regarding these proposed status changes.

 

*Note that the term ‘location’ defines a geographically or ecologically distinct area in which a single threatening event can rapidly affect all individuals of the taxon present. The size of the location depends on the area covered by the threatening event and may include part of one or many subpopulations. Where a taxon is affected by more than one threatening event, location should be defined by considering the most serious plausible threat (IUCN 2001, 2012).

 

References

Baptista, L. F.; Trail, P. W.; Horblit, H. M.; Boesman, P. 2017. Andaman Cuckoo-dove (Macropygia rufipennis). In: del Hoyo, J., Elliott, A., Sargatal, J., Christie, D.A. & de Juana, E. (eds.). Handbook of the Birds of the World Alive. Lynx Edicions, Barcelona. (retrieved from http://www.hbw.com/node/54169 on 17 March 2017).

BirdLife International. 2001. Threatened birds of Asia: the BirdLife International Red Data Book. BirdLife International, Cambridge, U.K.

BirdLife International. 2017. IUCN Red List for birds. Downloaded from http://www.birdlife.org on 17/03/2017.

Clark, W. S., Christie, D. A.; Marks, J. S. 2017. Andaman Serpent-eagle (Spilornis elgini). In: del Hoyo, J., Elliott, A., Sargatal, J., Christie, D.A. & de Juana, E. (eds.). Handbook of the Birds of the World Alive. Lynx Edicions, Barcelona. (retrieved from http://www.hbw.com/node/53018 on 17 March 2017).

Collar, N. 2016. White-rumped Shama (Copsychus malabaricus). In: del Hoyo, J., Elliott, A., Sargatal, J., Christie, D.A. & de Juana, E. (eds.). Handbook of the Birds of the World Alive. Lynx Edicions, Barcelona. (retrieved from http://www.hbw.com/node/58486 on 7 October 2016).

Davidar, P.; Yoganand, T. R. K.; Ganesh, T.; Joshi, N. 1996. An assessment of common and rare forest bird species of the Andaman islands. Forktail 12: 135-142.

eBird. 2017. eBird: An online database of bird distribution and abundance [web application]. eBird, Cornell Lab of Ornithology, Ithaca, New York. Available: http://www.ebird.org. (Accessed: March 17, 2017).

Ezhilarasi, N.; Vijayan, J. 2008. Status and ecology of Andaman Crake. Submitted to Salim Ali Centre for Ornithology and Natural History, Coimbatore.

Fishpool, L.; Tobias, J. 2017. Andaman Bulbul (Pycnonotus fuscoflavescens). In: del Hoyo, J., Elliott, A., Sargatal, J., Christie, D.A. & de Juana, E. (eds.). Handbook of the Birds of the World Alive. Lynx Edicions, Barcelona. (retrieved from http://www.hbw.com/node/57927 on 17 March 2017).

Gibbs, D.; Barnes, E.; Cox, J. 2001. Pigeons and doves: a guide to the pigeons and doves of the world. Pica Press, Robertsbridge, U.K.

Imboden, C. 1975. A brief radio-telemetry study on Moreporks. Notornis 22: 221-230.

Islam, M. Z.; Rahmani, A. R. 2004. Important Bird Areas in India: Priority sites for conservation. Indian Bird Conservation Network: Bombay Natural History Society and BirdLife International, Mumbai and Cambridge.

IUCN. 2001. IUCN Red List Categories and Criteria: Version 3.1. Gland, Switzerland and Cambridge, UK: IUCN Species Survival Commission.

IUCN. 2012. Guidelines for Application of IUCN Red List Criteria at Regional and National Levels: Version 4.0. Gland, Switzerland and Cambridge, UK: IUCN.

König, C.; Weick, F. 2008. Owls of the World. Second Edition. London, UK: Christopher Helm.

König, C.; Weick, F.; Becking, J.-H. 1999. Owls: a guide to the owls of the world. Robertsbridge, U.K.: Pica Press.

Olsen, J.; Downs J. A.; Tucker, T.; Trost, S. 2011. Home-range size and territorial calling of Southern Boobooks (Ninox novaeseelandiae) in adjacent territories. Journal of Raptor Research 45(2): 136-142.

Pande, S.; Sant, N.; Ranade, S.; Pednekar, S.; Mestry, P.; Deshpande, P.; Kharat, S.; Deshmukh, V. 2007. Avifaunal survey of Andaman and Nicobar Islands, January 2007. Indian Birds 3 (5): 162-180.

Pryde, M.A. and Greene. T.C. 2016. Determining the spacing of acoustic call count stations for monitoring a widespread forest owl. New Zealand Journal of Ecology 40(1): 100-107.

Rasmussen, P. C.; Anderton, J. C. 2012. Birds of South Asia. The Ripley Guide. Vols. 1 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.

Rocamora, G.; Yeatman-Berthelot, D. 2017. Andaman Drongo (Dicrurus andamanensis). In: del Hoyo, J., Elliott, A., Sargatal, J., Christie, D.A. & de Juana, E. (eds.). Handbook of the Birds of the World Alive. Lynx Edicions, Barcelona. (retrieved from http://www.hbw.com/node/60573 on 17 March 2017).

Winkler, H.; Christie, D. A. 2017. Andaman Woodpecker (Dryocopus hodgei). In: del Hoyo, J., Elliott, A., Sargatal, J., Christie, D.A. & de Juana, E. (eds.). Handbook of the Birds of the World Alive. Lynx Edicions, Barcelona. (retrieved from http://www.hbw.com/node/56290 on 17 March 2017).

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3 Responses to Archived 2017 topics: A review of the status of endemic/near-endemic birds of the Andaman Islands currently listed as Near Threatened

  1. Hannah Wheatley (BirdLife) says:

    Based on available information, our preliminary proposals for the 2017 Red List would be to treat:

    Spilornis elgini as VU under criterion C2a(i)

    Otus balli as LC

    Ninox affinis as LC

    Rallina canningi as LC

    Dryocopus hodgei as VU under criterion C2a(i)

    Columba palumboides as NT under criterion C2a(i)

    Macropygia rufipennis as LC

    Treron chloropterus as NT under criterion C2a(i)

    Dendrocitta bayleii as VU under criteria C2a(i); D1

    Dicrurus andamanensis as LC

    Coracina dobsoni as LC

    Brachypodius fuscoflavescens as LC

    Kittacincla albiventris as LC

    There is now a period for further comments until the final deadline of 4 August, after which the recommended categorisations will be put forward to IUCN.

    Please note that we will then only post final recommended categorisations on forum discussions where these differ from the initial proposal.

    The final 2017 Red List categories will be published on the BirdLife and IUCN websites in early December, following further checking of information relevant to the assessments by both BirdLife and IUCN.

  2. Praveen J says:

    All decisions may be OK except for Coracina dobsoni
    Densities are rather low and Threatened Birds of India recommended for uplisting it to Near-Threatened – similar to some of the endemics proposed for NT.

  3. Hannah Wheatley (BirdLife) says:

    Recommended categorisations to be put forward to IUCN

    Following further review, the recommended categorisations for this species has been changed.
    Coracina dobsoni is now recommended to be listed as NT under C2a(i).

    Final 2017 Red List categories will be published on the BirdLife and IUCN websites in early December, following further checking of information relevant to the assessments by both BirdLife and IUCN.

Comments are closed.