Detailed Species Accounts from The

Threatened Birds of Asia: The BirdLife International Red Data Book

Editors N. J. COLLAR (Editor-in-chief), A. V. ANDREEV, S. CHAN, M. J. CROSBY, S. SUBRAMANYA and J. A. TOBIAS

Maps by RUDYANTO and M. J. CROSBY

Principal compilers and data contributors ■ BANGLADESH P. Thompson ■ BHUTAN R. Pradhan; C. Inskipp, T. Inskipp ■ CAMBODIA Sun Hean; C. M. Poole ■ CHINA ■ MAINLAND CHINA Zheng Guangmei; Ding Changqing, Gao Wei, Gao Yuren, Li Fulai, Liu Naifa, Ma Zhijun, the late Tan Yaokuang, Wang Qishan, Xu Weishu, Yang Lan, Yu Zhiwei, Zhang Zhengwang. ■ HONG KONG Hong Kong Bird Watching Society (BirdLife Affiliate); H. F. Cheung; F. N. Y. Lock, C. K. W. Ma, Y. T. Yu. ■ TAIWAN Wild Bird Federation of Taiwan (BirdLife Partner); L. Liu Severinghaus; Chang Chin-lung, Chiang Ming-liang, Fang Woei-horng, Ho Yi-hsian, Hwang Kwang-yin, Lin Wei-yuan, Lin Wen-horn, Lo Hung-ren, Sha Chian-chung, Yau Cheng-teh. ■ INDIA Bombay Natural History Society (BirdLife Partner Designate) and Sálim Ali Centre for Ornithology and Natural History; L. Vijayan and V. S. Vijayan; S. Balachandran, R. Bhargava, P. C. Bhattacharjee, S. Bhupathy, A. Chaudhury, P. Gole, S. A. Hussain, R. Kaul, U. Lachungpa, R. Naroji, S. Pandey, A. Pittie, V. Prakash, A. Rahmani, P. Saikia, R. Sankaran, P. Singh, R. Sugathan, Zafar-ul Islam ■ INDONESIA BirdLife International Indonesia Country Programme; Ria Saryanthi; D. Agista, S. van Balen, Y. Cahyadin, R. F. A. Grimmett, F. R. Lambert, M. Poulsen, Rudyanto, I. Setiawan, C. Trainor ■ JAPAN Wild Bird Society of Japan (BirdLife Partner); Y. Fujimaki; Y. Kanai, H. Morioka, K. Ono, H. Uchida, M. Ueta, N. Yanagisawa ■ KOREA ■ NORTH KOREA Pak U-il; Chong Jong-ryol, Rim Chu- yon. ■ SOUTH KOREA Lee Woo-shin; Han Sang-hoon, Kim Jin-han, Lee Ki-sup, Park Jin- young ■ LAOS K. Khounboline; W. J. Duckworth ■ MALAYSIA Malaysian Nature Society (BirdLife Partner); K. Kumar; G. Noramly, M. J. Kohler ■ MONGOLIA D. Batdelger; A. Bräunlich, N. Tseveenmyadag ■ MYANMAR Khin Ma Ma Thwin ■ NEPAL Bird Conservation Nepal (BirdLife Affiliate); H. S. Baral; C. Inskipp, T. P. Inskipp ■ PAKISTAN Ornithological Society of Pakistan (BirdLife Affiliate) ■ PHILIPPINES Haribon Foundation for Conservation of Natural Resources (BirdLife Partner); N. A. D. Mallari, B. R. Tabaranza, Jr. ■ RUSSIA Russian Bird Conservation Union (BirdLife Partner Designate); A. V. Andreev; A. G. Degtyarev, V. G. Degtyarev, V. A. Dugintsov, N. N. Gerasimov, Yu. N. Gerasimov, N. I. Germogenov, O. A. Goroshko, A. V. Kondrat’ev, Yu. V. Labutin, N. M. Litvinenko, Yu. N. Nazarov, V. A. Nechaev, V. I. Perfil’ev, R. V. Ryabtsev, Yu. V. Shibaev, S. G. Surmach, E. E. Tkachenko, O. P. Val’chuk, B. A. Voronov. ■ SINGAPORE The Nature Society (Singapore) (BirdLife Partner); Lim Kim Seng ■ SRI LANKA Field Ornithology Group of Sri Lanka (BirdLife Affiliate); S. Kotagama; S. Aryaprema, S. Corea, J. P. G. Jones, U. Fernando, R. Perera, M. Siriwardhane, K. Weerakoon ■ THAILAND Bird Conservation Society of Thailand (BirdLife Partner); U. Treesucon; R. Jugmongkol, V. Kongthong, P. Poonswad, P. D. Round, S. Supparatvikorn ■ VIETNAM BirdLife International Vietnam Country Programme; Nguyen Cu; J. C. Eames, A. W. Tordoff, Le Trong Trai, Nguyen Duc Tu.

With contributions from: S. H. M. Butchart, D. S. Butler (maps), P. Davidson, J. C. Lowen, G. C. L. Dutson, N. B. Peet, T. Vetta (maps), J. M. Villasper (maps), M. G. Wilson Recommended citation BirdLife International (2001) Threatened birds of Asia: the BirdLife International Red Data Book. Cambridge, UK: BirdLife International.

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ISBN 0 946888 42 6 (Part A) ISBN 0 946888 43 4 (Part B) ISBN 0 946888 44 2 (Set)

British Library-in-Publication Data A catalogue record for this book is available from the British Library

First published 2001 by BirdLife International

Designed and produced by the NatureBureau, 36 Kingfisher Court, Hambridge Road, Newbury, Berkshire RG14 5SJ, United Kingdom

Available from the Natural History Book Service Ltd, 2–3 Wills Road, Totnes, Devon TQ9 5XN, UK. Tel: +44 1803 865913 Fax: +44 1803 865280 Email [email protected] Internet: www.nhbs.com/services/birdlife.html

The presentation of material in this book and the geographical designations employed do not imply the expression of any opinion whatsoever on the part of BirdLife International concerning the legal status of any country, territory or area, or concerning the delimitation of its frontiers or boundaries. Threatened birds of Asia

NARCONDAM HORNBILL Aceros narcondami

Critical — Endangered — Vulnerable D1; D2

This hornbill qualifies as Vulnerable because it has a very small population on one tiny island. It appears to be stable despite limited hunting and habitat degradation. Feral goats are preventing forest regeneration.

DISTRIBUTION The Narcondam Hornbill has one of the smallest natural ranges of any bird species, being known from: ■ INDIA Narcondam, a tiny (<7 km2) outlier of the Andaman Islands in the Bay of Bengal, where it is found throughout (see next section). However, the observation that low-lying areas of the island (below 300 m) hold the majority of older birds (with many chevrons on the casque), while the upper areas hold mostly young birds (possibly under three years old) (R. Sankaran in litt. 1999), strongly suggests that the lower areas are more important and valuable for the species, presumably owing to the quantity and/or quality of nest sites and/or food trees.

POPULATION All accounts have described the species as common (Stray Feathers 1 [1873]: 404–416, Hume 1873a, St John 1899, Cory 1902, Abdulali 1971), and it has been considered “easily the most abundant species on the island” (Abdulali 1976). Osmaston (1905) estimated

NORTH ANDAMAN

ANDAMAN ISLANDS (INDIA)

MIDDLE ANDAMAN

SOUTH ANDAMAN

LITTLE ANDAMAN ISLAND The distribution of Narcondam Hornbill Aceros narcondami: (1) Narcondam. Recent (1980–present)

1860 Aceros narcondami the population to comprise around 200 individuals. Based on a 24-day study in March– April 1972, this figure was revised upward to a “liberal estimate” of 400 (S. A. Hussain 1993); during this visit, nine nests were found, the highest count on one day was 72 males and 28 females, and there were 728 sightings of males compared to only 149 of females, this sex bias presumably being related to the fact that many females would have been incarcerated in nesting chambers (Hussain 1984a; also Abdulali 1976). More recently, in 1998, the population was estimated at between 295 and 320 birds; 17 nests were then found, and it was estimated that there were 68–85 breeding pairs on the island (R. Sankaran in litt. 1999). On this basis it seems probable that the population has been fairly stable ever since it was first discovered.

ECOLOGY Habitat Narcondam is an extinct volcano with an area of 6.82 km2, almost entirely covered in sparse dry forest and rising steeply to a central peak (706 m), and the hornbills are present throughout the island except on the grassy slopes that dominate the south and south-east aspects of the hill (Hussain 1984a, R. Sankaran in litt. 1999). Food Fig Ficus fruits form a large proportion of the diet (Abdulali 1971), but at least 33 types of fruit are exploited (R. Sankaran in litt. 1999). However, based on the seeds collected at the middens below nests, over 80% of the fruits provided (excluding Ficus) at the nest belong to three species, Caryota mitis, Sterculia rubiginosa and a member of the Meliaceae; apart from fruits, animal matter—mostly mantids—is provided at the nest, but spiders, crabs and a lizard have been recorded (R. Sankaran in litt. 1999). The male alone does all the provisioning: in one instance when a chick remained in the nest for five days after its mother and sibling had emerged, the female did not provision the chick but accompanied the fledgling; but both the male and the female feed the chicks after they have fledged (R. Sankaran in litt. 1999). Breeding Nesting begins in early February (Hussain 1984a). In April 1969 many birds were breeding (Abdulali 1971), and in March and April 1972 “breeding was in full swing” (Abdulali 1976). As with other Aceros hornbills, the female is sealed in a tree cavity within which she sheds her flight feathers and is incapable of flight for the duration of the breeding cycle (Hussain 1984a). Recorded nest heights range from as low as 1.6 up to 28 m (Abdulali 1976, Hussain 1984a, R. Sankaran in litt. 1999), although over 40% are between 10 and 15 m, with holes in the trunk and those at the end of broken branches being used with equal frequency (R. Sankaran in litt. 1999). Seven species of tree have been recorded for nesting, the two most popular being Tetrameles insignis and an unidentified species; around 60% of nests are at the lower reaches of the hill below 100 m, 30% between 100 and 200 m, and 10% above 200 m (R. Sankaran in litt. 1999). The clutch contains two eggs (Hussain 1984a, R. Sankaran in litt. 1999). In all nests monitored, both chicks fledged successfully (R. Sankaran in litt. 1999), whereas most other large hornbills are only capable of raising one chick (Kemp 1979). Hatching is asynchronous: in one nest described by Hussain (1984a) one chick hatched an estimated 10 days after the other. There is no indication of territorial behaviour during the breeding season, with alien adults tolerated close to the nest site, and the minimum recorded distance between neighbouring nests being only 22.8 m (Hussain 1984a). Males constantly visit the nest cavity with food for both mate and offspring, often following regular lines of flight from nest holes and generally returning every 10–30 minutes (Abdulali 1976).

THREATS The Narcondam Hornbill is (now) the one threatened bird species that is entirely restricted to the “Andaman Islands Endemic Bird Area”, threats and conservation measures in which are profiled by Stattersfield et al. (1998). For this species, constrained by the limits of its island home, range and population size are threats in themselves. Although it has clearly survived for aeons with a maximum of 400 individuals and a total range of under 7 km2, the population is permanently susceptible to stochastic events such as climatic disasters

1861 Threatened birds of Asia and disease. To minimise this threat, any reduction in hornbill numbers or habitat extent on Narcondam should be avoided. The following information, unless otherwise cited, is compiled from R. Sankaran (in litt. 1999). The primary threats arise from the establishment of a police outpost on the island, manned by 17 personnel, in 1969. In 1976 the police introduced several pairs of goats, which by 1998 had grown to a population of 130–150 domestic animals in the police camp and over 250 feral animals at large on the island, as a result of which there is very little natural woodland regeneration in evidence. In 1972, human presence on the island was a “recent phenomenon”, and it was speculated that the consequent disturbance would reduce the proportion of nests positioned low in trees (Hussain 1984a). Historically, the gravest threat to endemic taxa on small islands has been the arrival of man and his associated fauna; thus the threats posed by even the small-scale colonisations of Narcondam should be guarded against rigorously (Hussain 1984a, Hussain 1991b). Despite such concern, about 2–3 ha of forest have been lost to the creation of the camp and an adjacent plantation of fruit trees and vegetable plots, and a little more has been degraded. At least 10–12 live standing trees are cut each year for fuelwood for the camp, and over 500 poles were cut during a three-month period to make and repair fences that prevent goats from entering the vegetable plots. Competition for nest sites is presumably intense; this factor and the lack of natural predators presumably gave rise to the usage of very low nests. Regular cyclones destroy many older trees with suitable cavities (Hussain 1984a) and any cutting of large old trees is likely to have a detrimental impact on the island’s hornbill population. Up to very recently, outposted police staff hunted Narcondam Hornbills for meat. Some 7–10 birds were shot in a three-month period and the probable annual loss was estimated at 25–40 birds, although in view of the large number of chicks produced each year, it may be that hunting pressure was not a very serious threat (R. Sankaran in litt. 1999; see Measures Taken). There is also a sizeable population of domestic and feral cats on the island, although whether they prey on the hornbill is not known.

MEASURES TAKEN The species is listed in Schedule I of the Wildlife Protection Act, 1972, and on Appendix II of CITES. Narcondam Island has been protected as a wildlife sanctuary since February 1977 (Pande et al. 1991). Senior officials have been briefed on the hunting problem, and strict instructions have been issued to personnel on the island prohibiting all hunting of hornbills (R. Sankaran in litt. 1999).

MEASURES PROPOSED The complete removal of goats from the island appears to be a priority and has been due for some time to be implemented (B. F. King verbally 1998). The provision of cooking fuel to islanders has been proposed as a way to eliminate their requirement for fuelwood. It has also been suggested that a second population of the Narcondam Hornbill might be established on another suitable island in the Andamans (Hussain 1984a). However, at this stage an introduction or translocation project should only be countenanced as an emergency measure in the event of serious population declines or a natural disaster. Before any such action, an ecological appraisal of any recipient island should be undertaken to clarify what organisms the hornbill would compete with for nest-sites and food; it is almost certainly more sensible to boost the size and resilience of the Narcondam population by addressing the goat problem, planting additional fig trees and providing nest- boxes (M. F. Kinnaird in litt. 2000).

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