Iwan Setiawan (PHPA/BirdLife International - Indonesia Programme - Laporan No. 6, 1996), published a report on 'The Status of Sulphur-crested Cockatoo (Cacatua sulphurea parvula) on Nusa Penida, Bali and Sumbawa, West Nusa Tenggara. Below article cites the relevant information to Nusa Penida, and omits information on Sumba and Sumbawa.
Image right: Setiawan, PHPA/BirdLife International - Indonesia Programme - Laporan No. 6, 1996: cover
In the 1940s, there were large flocks of these birds on the island, but it becomes clear that the Cacatua sulphurea parvula has become almost extinct in Nusa Penida in 1996.
Key point summary and recommendations
1.1 The Yellow-crested Cockatoo Cacatua sulphurea is endemic to Indonesia; the sub-species C. s. parvula is distributed from Nusa Penida (Bali) eastwards through the Lesser Sunda chain of islands from Lombok to Alor, and Timor.
1.2 Based on interviews and surveys conducted on Nusa Penida, there are indications of a sharp population decline in the population in last few years. This report presents the results of surveys conducted in November and December 1994, which aimed to make a rapid evaluation of the status of the species in Nusa Penida, and Sumbawa.
1.3 The results of the survey show that the species has suffered a dramatic population decline on these islands; just six birds remain on Nusa Penida. On Sumbawa the situation is less critical but the species is extinct in some areas where it formerly occurred.
1.4 The primary cause of the decline is over-harvesting. Large tracts of suitable forest habitat are still present on Sumbawa, but extraction of nest trees for construction of houses is an additional pressure. Following representations from BirdLife, catch quotas for C. sulphurea were suspended by PHPA in June 1992 pending the results of a status assessment of the species in the wild.
1.5 In view of the rarity of C. s. parvula, it is recommended that it be included in the list of Indonesian protected species.
1.6 Furthermore, it is recommended that district officers be requested to issue a local decree (PERDA) to protect C. sulphurea and its nest trees, and that PHPA assist with distribution of the decree to all sub-districts in the region.
1.7 Communities in the region should be made aware of the critical conservation status of the species, through local media and other appropriate means.
(p.2) The Yellow-crested Cockatoo (Cacatua sulphurea) is endemic to Indonesia; its distribution includes the Masalembo Islands (C. s. abbotti), Nusa Penida and Nusa Tenggara from Lombok to Timor (C. s. parvula), Sulawesi (C. s. sulphurea) and Sumba (C. s. citrinocristata) (Map 1). Currently, the species is not protected in Indonesia, but all sub-species are included in Appendix II of CITES (Convention on International Trade in Endangered Species of Wild Fauna and Flora). Under the convention, such species may only be traded between countries if it can be demonstrated that this will not be detrimental to their survival.
The sub-species C. sulphurea are not listed as protected fauna under Act of the Republic of Indonesia No. 5/1990 concerning the Conservation of Living Resources and their Ecosystems. However, based on a Ministerial Decree (SK Menteri Kehutanan No. 1/1983), a permit from the Directorate General of PHPA is required for the catching, trading, owning, captive breeding and transportation of the species.
C. sulphurea is included in Appendix II of CITES. In 1984, the catch quota for C. sulphurea was 13,125 birds (Anon 1984); the quota was reduced to 5,000 in 1991. C. s. parvula is included in the quotas allocated to NTB (Appendix 2). Following representations from BirdLife, catch quotas for C. sulphurea were suspended by PHPA in June 1992 pending the results of a status assessment of the species in the wild.
The sub-species C. s. parvula is endemic to the islands of Nusa Penida (Bali) and the island chain of West Nusa Tenggara, which includes Lombok, Sumbawa, Padar, Rinca, Flores, Pantar, Alor, Semau, and Timor (White & Bruce, 1986; Forshaw & Cooper, 1989). Information on the status of C. s. parvula is limited. However, it has recently been reported from Nusa Penida, Enpang and Batu Hijau on Sumbawa (Helvoort et al., 1986; Gibbs, 1990; Buchart et al., 1993). The species is quite common on Komodo and still encountered in the Manggarai District, Flores, and Alor in small flocks, as well as in Timor (Holmes, pers. comm.; Anon., 1989a; Anon., 1989b; Teguh, pers. comm.).
C. sulphurea is described as endangered according to IUCN threat criteria (Collar et al.,1994; Shannaz et al., 1995). There have been few surveys on the status of C. sulphurea, and PHPA/BirdLife International are currently conducting a status assessment of the species, including a field survey programme. This report presents the results of a survey conducted by PHPA/BirdLife International from 17 November to 30 December 1994 on Nusa Penida and Sumbawa.
Nusa Penida (115°25'-115°37'E, 8°40'-8°49'S) in the administrative district of Klungkung in the province of Bali, is divided into 12 village districts. It is part of a small island group: Nusa Ceningan, Nusa and Nusa Penida. Nusa Penida (19,126 ha) is the biggest of the three islands. The highest summit on the island is Mundi hill (529 m a.s.l.). The island is very dry; the wet season is between December and March. Almost all of the island has been converted to agriculture, and the only remaining natural forests are areas of a few hectares located around the temples (it as pura). Agricultural activity is confined to the wet season, and the principal crop is maize. The majority of the population are farmers and cattle breeders, although in the last few years some people have turned to farming sea grass.
Map 1. (left): Distribution history Cacatua sulphurea; Sub-species: C.s. abbotti; C. s. sulphurea; C. s. citrinocristata; C. s. parvula (p.3)
The survey aimed to gain a general overview of the current status and distribution of C s. parvula on Nusa Penida, Bali, and Sumbawa, West Nusa Tenggara and had the following objectives: 1. to identify areas where the sub-species is still present; 2. to collect basic information on habitat and breeding; 3. to collect information related to the conservation of the sub-species and to evaluate the cause of the population decline on Nusa Penida and Sumbawa.
Approach and Methodology
Because of the large area to be surveyed, it was impractical to use a standard census methodology, and instead it was decided to employ a combination of direct searching and a rapid rural appraisal (semi-structured interview) approach.
A semi-structured interview is an informal discussion, which aims to gather the information needed. A general questionnaire was prepared in advance, but this was not shown to the respondents in order to reduce the risk of being influenced by form. Interviews were conducted with a cross-section of the community, but with special emphasis on native residents, aged above 40 years and living in areas near forest below 500 m a.s.l.
If, from the interviews, information was received on locations where cockatoos were thought to have been present in the last few years, these areas were visited and a "find and count" method employed along selected transects. Surveys were conducted between 05.30-09.00 hr and 15.30 - 18.00 hr. On Nusa Penida, 10 x 1 km2 trails were walked on 30/11/94.
Status assessment of C. s. parvula on Nusa Penida - Current status - Nusa Penida
(p.7) Forty-four respondents in five villages were interviewed on 28/12/94 - 30/12/94 (Map 2); all respondents were farmers. Thirty four respondents (77%) confirmed that cockatoos occurred in two locations. In those places the cockatoos were seen in the fields and in the pura (a Hindu place of worship). Only 34 respondents (70%) reported that they had seen cockatoos in 1994, and they were most frequently seen in March and April. During 1994, it was reported that cockatoos could be found only in two villages on Nusa Penida. Subsequently, observations were made in the two villages, namely Sedihing (Tanglad village) and Suane (Karang village).
Summary of results from semi-structured interview on status
1. Is the cockatoo present? Yes 24 (77.27%); No 10,(22,73%)
2. How often do you see cockatoos? Rare (0); Very rare 34(77,27%); Don't know: 10 (22,73%)
3. Which year did you last see the cockatoos? 1965-1970: 10 (22,753 %); 1989-1991: 3 (6,81 %); 1994: 31 (70,45 %)
4. In which months were the birds most often seen? 3-4: 44 (100,00%); 5-8: (0) 9-12: (0); 1-2 (0)
5. Since when have the birds and why? 1965 5 (11.36%) catching; 1970-1975: 19 (43.18%) catching; 1982-1983: 15 (34,09%) catching
Summary of results from semi-structured interview on habitat
1. Where were the birds usually seen before 1994? Dry land agricultural area: 42 (95,45%); Forest and dry land agricultural area: 2 (4,55%)
2. Place cockatoos now most commonly seen: Dry land agricultural area: 43 (97,72%); Forest: 1 (2.27%)
A survey was conducted in Sedihing hamlet on 29/12/94 and three cockatoos were seen roosting in a Kepah tree (Sterculia foetida). A nesting hole was present in the trunk about 6-7m above the ground. The roosting and nesting tree was located on the "Gunung Sari" pura. For six years the cockatoos have not fledged young, even though since 1989 there has been an awig-awig or regulation that prohibits catching or taking of cockatoos in the pura. In Karang hamlet a survey was made on 30/12/94 and four cockatoos were seen roosting in a Kutuh tree, which also contained a nest hole. The tree is situated within the corpse-burning field for the ngaben ceremony.
At this village, a villager was in possession of a captive 5-month old cockatoo. The cockatoo was taken as a chick from a Kutuh tree, even though this village has an awig-awig that those who capture cockatoos must pay a fee of up to U$ 100 (Rp. 200,000.00).
Image above: Map 2: Survey location and signings of C.s. parvula on Nusa Penida, Bali (p.5)
Nusa Penida Ecology
(p.9) The nesting habitat C. s. parvula is the forest around the pura (89%); nest trees were of two species, kepah (Sterculia foetida) and kutuh. Seventy-three percent of respondents reported that nest hole height was 6 - 10 m, and that the location of the nest was in the trunk (75%). Two eggs are laid (68%).
Summary of results from semi-structured interview on breeding ecology
1. Nesting habitat = Forest: 39 (88.64%); don't know 5 (11,36%)
2. Nesting tree = Kepah: 19 (43,18%); Kutuh: 15 (34,09%); don't know: 10 (22,73%)
3. Height of nesting = 6-10m: 32 (72,73%); don't know: 12 (11,36%)
4. Nesting location = trunk: 33 (75%); second branch: 2 (4,55%); don't know: 9 (20,45%)
5. Number of eggs = 2 eggs: 30(68,81%); don't know: 14 (31,82%)
During the survey the cockatoos were seen roosting in kepah and kutuh trees around pura, where there are also nest holes. The island has 14 villages and pura nesting occurs at two of the pura. The depth of the nest hole is 0.5 - 2m. There have been professional bird trappers on this island for 25 years.
Appendix 3 (below): Vegetation used as food source and nesting site; Note: a). based on interview; b). based on observation (p.19). This table gives sources for the entire distribution of the Cacatua suplphurea in Indonesia; local names, wherever possible, are given in English.
|1.||Kore (Caloptropis gigantea)||+ b)|
|2.||Tonang (aphanamicys plystachya)||+ a)|
|3.||Rice (Oryza sativa)||+ b)|
|4.||Corn (Zea mays)||+ b)|
|5.||Kelor (Moringa oleifera)||+ b)|
|6.||Sorgum (Andropogon sorghum)||+ a)|
|7.||Dadap (Erytrine fusca)||+ b)||+ a)|
|9.||Kemiri (Aleurites moluccana)||+ a)|
|10.||Mango (Manggifera indica)||+ b)|
|11.||Ficus (Ficus benyamina)|
|13.||"Kapok"/Randu (Ceiba petandra)||+ a)||+ a)|
|14.||Coconut (Cocos nucifera)||+ a)||+ a)|
|15.||Tamarind/Asam (Tamarindus indica)||+ b)||+ a)|
|16.||Binong (Tetrameles nudiflora)||+ b)|
|17.||"Flame tree"/Buru (Erythrina sp)||+ a)|
|18.||Lean (Macarangga spp)||+ a)|
|19.||Manggo (Eugenia spp)||+ a)|
|20.||Kelanggo (Duabanga moluccana)||+ b)|
|22.||Garuga/"Wou" (Garuga floribunda)||+ a)|
|25.||Kepah (Sterculia foetida)||+ b)|
Causes of Decline: Nusa Penida
(p.10) Seventy-seven percent of respondents reported a decline in the abundance of cockatoos. Nineteen of respondents said that the decline commenced in 1965 (19.36%), 43% between 1982-1983. All respondents considered cockatoos to be a pest of maize crops (93%). Measures reported to combat cockatoo damage were chasing the bird (29%), catching (27%), and capturing the chicks (22%). The timing of capture is not definite. The commonest method of catching was (p.11) said to be taking chicks from the nest (88%); only 4% of respondents said that trapping with resin was used. All respondents said that the birds were sold to buyers and middlemen from the city. The selling price of the bird was put at Rp 40,000-50,000 (34%), Rp 80,000-100,000 (36%) and Rp 100,000 - 300,000 (18%). The trappers were mostly local residents (59%).
Appendix 4 (below). Summary of results from semi-strucured interviews on the habitat and status of C.s. parvula (p.20-22). Below table has been adapted to represent relative data to Nusa Penida only.
|Place||Date||Number interviewed||Altitude (m.a.s.l.)||Habitat||Stiull present||How often seen||Last seen||Increase or decrease||When last common & cause of decline|
|Nusa Ceningan||28/12/94||2||5||dryland agriculture||No (2)||-||3-4 (1965/2)||3-4 (2)||1965 (2), catching|
|Sekartaji||29/12/94||4||75||dryland agriculture||Yes (4)||Very rare (4)||1-3 (1989/1), 2 (1991/2), 4 (1994/1)||3-4 (4)||1962 (1), 1965 (2), 1970 (1), catching|
|Tanglad||29/12/94||15||150||dryland agriculture||Yes (15)||Very rare (15)||3 (1994/15)||3-4 (15)||1982-1983 (15), catching|
|Suane||30/12/94||15||150-200||dryland agriculture||Yes (15)||Very rare (15)||4-6 (1994/15)||3-4 (15)||1970-1975 (10), catching|
|Batumadeg||30/12/94||8||50||dryland agriculture||No (8)||-||2-5 (1970/8)||3-4 (8)||1970 (8) catching|
Summary of results from semi-structured interview on the damage caused and catching of C. s. parvula
1. Do cockatoos disturb agriculture? Yes: 44 (100%); No (0)
2. Kind of crops attacked by the bird: Maize: 41 3 (6,82%); don't know 3 (6,82%)
3. Measures taken against disturbance: Catching: 12 (27,27%): Chasing: 13 (29.55%): Taking the chicks: 10 (22,73%); don't know: 12 (27.27%)
4. Time of catching: 3-4 months: 4 (9,09%); 10-11 months: 7 (15,91%); Not definite: 21 (47,73%): don't know: 3 (6,81%)
5. Methods of catching: Resin: 2(4,55%); Taking the chicks: 39 (88,64%); don't know: 3 (6,81%)
6. Catching activity: Regular: 2 (4,55%); Irregular 20 (45,55%); don't know: 22 (50%)
7. People practising catching: Local people: 26 (59,09%); Local people and outsiders: 4 (9,09%); outsiders 2 (4,55%)
8. Yield: Sold: 44 (100%)
9. Person to whom catch sold: Buyer and middleman 44 (100%)
10. Price (Rp) 40,000-50,000: 15 (34,09%); 80,000-100,000: 16 (45,45%); 100,000-3000: 8 (18,18%); don't know: 2 (2,27%)
11. Agree/Not agree with catching: No: 31 (70,45%); Yes: 8 (18,18%); don't know 5 (11,36%)
Appendix 5 (below). Summary of results from semi-structured interviews on habitat, place of sighting and measures taken against raids by C.s. parvula. Below table has been adapted to represent relative data to Nusa Penida only.
|Place||Date||Number interviewed||Altitude (m.a.s.l.)||Place usually seen before 1994||Place species ususally seen||Cockatoo seen as pest (Yes/No)||Crops raided by the bird||Measures taken against raiding||Catching period|
|Nusa Ceningan||28/12/94||2||5||dryland ag. (2)||dryland ag. (2)||Yes (2)||maize (2)||catching (2)||3-4 (2)|
|Sekartaji||29/12/94||4||75||forest, dryland ag. (2)||forest (1), dryland ag. (3)||Yes (4)||maize (4)||taking the chicks (4)||3-4 (2), don't know (2)|
|Tanglad||29/12/94||15||150||dryland ag. (15)||dryland ag. (15)||Yes (15)||maize (15)||taking the chicks (10), don't know (5)||not definite (8); don'y know (7)|
|Suane||30/12/94||15||150-200||dryland ag. (15)||dryland ag. (15)||Yes (15)||maize (15)||catching (5) & chasing (10)||10-11 (7), not definite (5)|
|Batumadeg||30/12/94||8||50||dryland ag. (8)||dryland ag. (8)||Yes (15)||maize (5), don't know (3)||catching (5), chasing (3)||not definite (8), don't know (3)|
(p.14) Available evidence (see Forshaw and Cooper, 1989) suggests that C. sulphurea is a species of lowland forest, but within limits it is able to tolerate the conversion of forest to agricultural areas. No research has yet concluded that the species is able to live in agricultural areas, but in natural systems the species feeds on seeds, berries, fruit and blossoms of fruit trees. The species readily adapts to feed on agricultural crops, and this study concludes from results
obtained on Sulawesi at Cacatua raids maize crops.
C. s. parvula may be able to tolerate the conversion of forest to agricultural areas; in fact the species may even benefit from the increase in food resources provided by crops. Large-scale conversion of forest to agricultural areas, as has occurred in several areas in Nusa Penida and Sumbawa, must have reduced overall population levels; respondents in our survey offered loss of nesting trees as the cause of decline. This study is unable to offer new evidence on the effect of agricultural development of cockatoo populations; it does, however, strongly suggest that it is over-harvesting that has brought about the current extreme rarity of the species.
In 1989, dusun Sedihing in Nusa Penida declared an awig-awig or regulation that prohibits the catching or owning of birds (especially cockatoos). In 1980, dusun Karang declared an awig-awig which permitted residents to take cockatoo chicks from the nest or fallen chicks and pay a fee of Rp 200.000. This regulation is very helpful but not well controlled, thus not much help in the conservation of the species. In 1970-1975, there were eight birds in dusun Karang, but by 1994 only four birds and one chick were left. It is evident that the regulation is not effective. In dusun Sedihing there are only three birds left. They have not bred in the last six years and are assumed all to be the same sex.
This is a cause for great concern, and must be corrected and controlled immediately. It should be understood that, without further study, the population level cannot be raised by introducing birds from other areas. Based on these observations, there is evidence that the conversion of forest to agricultural areas has little effect on the cockatoos; over-harvesting is strongly suggested as the cause of population decline.
Appendix 6. Summary of results from semi-structured interviews on the breeding ecology of C.s. parvula. Below table has been adapted to represent relative data to Nusa Penida only.
|Place||Date||Number interviewed||Altitude||Nesting habitat||Nesting tree||Height of nest||Site of nest||Number of eggs|
|Nusa Ceningan||28/12/94||2||5||don't know (2)||Kepah (3)||-||-||-|
|Sekartaji||29/12/94||4||75||temple forest (4)||Kepah (4)||7-10 (1), 10 (3)||trunk (2). second branch (2)||2|
|Tanglad||29/12/94||15||150||temple forest (12), don't know (3)||Kepah (15)||10 (13)||trunk (13)||2|
|Suane||30/12/94||15||150-200||temple forest (15)||Kepah (15)||6-10 (15)||trunk (15)||2|
|Batumadeg||30/12/94||8||50||temple forest (8)||-||-||trunk (3)||-|
Conclusion and Recommendations
C. s. parvula has suffered a dramatic population decline in Nusa Penida and Sumbawas. It is now very rare or extinct in areas where it formerly occurred. Over-harvesting is the cause of a dramatic decline in the last 10 to 15 years. This has resulted from a combination of the species' flocking behaviour and extremely efficient trapping methods. The species urgently requires strict protection to enable the population to recover, which is likely to take many years. Even if the species became plentiful again, the reopening of catch quotas at a future (p.15) date should be viewed with extreme caution because of the inherent difficulties of developing and enforcing harvesting procedures which would avoid local extinction.
This study is part of a series of surveys of C. sulphurea that will contribute to the composition of a management plan for the species. Reports from Masalembo Islands, Central Sulawesi, North Sulawesi and South Sulawesi (Cahyadin et al. 1994a; Cahyadin et al. 1994b; Holmes 1990) indicated that the situation in these provinces is similar to that on Nusa Penida and West Nusa Tenggara. The following recommendations are therefore made for C. s. parvula across its range in Nusa Penida, Bali and Sumbawa, West Nusa Tenggara.
1. The sub-species should immediately but put on the list of protected fauna, which include: a. List of Indonesian protected species under Act of the Republic of Indonesia No. 5 of 1990, concerning Conservation of Living Resources and Their Ecosystems; b. PHPA requested all Camats in West Nusa Tenggara to publish C. s. parvula as soon as possible.
2. The situation must be made known to community leaders and local residents to obtain support for the protection of the remaining C. s. parvula by: a. Circulating copies of the legislation/decrees to all Camats (Sub-district heads) through the KSDA with a request that the communicate this information to the community; b. Media publicity through local papers and local radio stations; c. Circulation of a simple poster to all schools in the province via SSKSDA offices of PHPA.
3. The most immediate and efficient action would be to publish local government regulation PERDA to protect C. s. parvula by the local government level I and II (Pemerintah Daerah Tingkat II and Pemerintah Daerah Tingkat I).
Appendix 7 (below). Summary of results from semi-structured interviews on the catching of C.s. parvula. Below table has been adapted to represent relative data to Nusa Penida only.
|Place||Date||Number interviewed||Altitude||Method of catching||Catching frequency||Result of catching||Where catch sold||Price (Rp)||Catcher||Agree/not agree with catching|
|Nusa Ceningan||28/12/94||2||5||resin (2)||regular (2)||sold (2)||buyers & middlemen (2)||-||local people (1), outsider (1)||no (2)|
|Sekartaji||29/12/94||4||75||taking the chick (4)||irregular (2), don't know (2)||sold (4)||buyers & middlemen (4)||80,000-100,000 (2)||local people (1), outsider (1)||no (4)|
|Tanglad||29/12/94||15||150||taking the chick (15)||no (8), don't know (7)||sold (15)||buyers & middlemen (15)||80,000 (3), 100,000 (7), millions (2)||local people & outsiders (4)||no (7), yes (8)|
|Suane||30/12/94||15||150-200||taking the chick (12)||no (10), don't know (10)||sold (15)||buyers & middlemen (15)||40,000-50,000 (15)||local people (15)||no (15)|
|Batumadeg||30/12/94||8||50||taking the chick (8)||don't know (8)||old (8)||buyers & middlemen (8)||100,000-300,000 (8)||local people (8)||no (3)|
- Anon. 1989a. Laporan Satwa Liar Kakatua Jambul Kuning (Cacatua sulphurea) dan Beo (Gracula religiosa) Di Kabupaten Mangarai. Departemen Kehutanan, Dirjen PHPA,Sub Balai KSDA VII Kupang.
- Anon. 1989b. Laporan Inventarisasi Satwa Liar Kakatua Jambul Kuning (Cacatua sulphurea) dan Beo (Gracula religiosa) Di Kabupaten Alor. Departemen Kehutanan, Dirjen PHPA, Sub Balai KSDA VII Kupang.
- Anon. 1984. Penetapan Penambahan/Pengurangan Jatah Penangkapan/Pengambilan Satwa Liar/Hasil Satwa Liar yang Tidak Dilindungi Undang-Undang untuk Periode Tahun 1991. Surat Keputusan Direktorat Perlindungan Hutan dan Pelestarian Alam No. 7/Kpts/VI sek/Prog/84. Tidak dipublikasikan.
- Anon. 1991. Penetapan Jatah Penangkapan/Pengambilan Tumbuhan dan Satwa Liar/Hasil Tumbuhan dan Satwa Liar yang Tidak Dilindungi Undang-Undang untuk Periode Tahun 1991. Direktorat Jenderal Perlindungan Hutan dan Pelestarian Alam.Tidak dipublikasikan.
- Butchart J.H.M., T.M. Brooks, C.W.N. Davies, G. Dharmaputra, G.C.L. Dutson, J.C. Lowen and A. Sahu. 1993. Preliminary Report of the Cambridge Flores/Sumbawa Conservation Project. Unpublished.
- Cahyadin, Y., P. Jepson, dan S. Arif. 1994. Status Cacatus sulphurea abbotti di Kepulauan Masalembo [The Status of Cacatua sulphurea abbotti on the Masalembo Islands]. PHPA/BirdLife International, Bogor. Laporan No. 2.
- Cahyadin, Y., P. Jepson, dan M. Syarief. 1994. Telaah Singkat Status Cacatua sulphurea sulphurea di Propinsi Sulawesi Selatan, Indonesia [A Rapid Status Assessment of Cacatua sulphurea sulphurea in South Sulawesi Province, Indonesia]. PHPA/BirdLife International, Bogor. Laporan No. 3.
- Forshaw, J. and W. T. Cooper. 1989. Parrots of the World. Third (revised) Edition. Weldon Willoughby, NSW. Australia.
- Gibbs, D. 1990. Wallacea: A Site Guide for Birdwatchers. Unpublished.
- Helvoort, S. E. van, P. Hartojo., and Swastika. 1996. Laporan Sementara Peninjauan Kepulauan Nusa Penida, Bali.
- Holmes, D. A. and P. Andrew. 1990. Sulawesi Bird Report. Kukila Volume 5 No. 1, Jakarta.
- Shannaz, J., P. Jepson., dan Rudyanto. 1995. Burung-burung Terancam Punah di Indonesia. PHPA/BirdLife International Indonesia Programme. Bogor, Indonesia.
- White, C.M.N & M.D. Bruce. The Birds of Wallacea (Sulawesi, The Mollucca & Lesser Sunda Islands, Indonesia). British Ornithologist Union Checklist No. 7. BOU, London.
Appendix 1. Questions for the semi-structured interview
- 1. Do you know this cockatoo?
- 2. Where do you see it?
- 3. How many cockatoos do you usually see?
- 4. Where do you most commonly see it?
- 5. When (month) do you see it in abundance?
- 6. Do you think there is a change in the number of birds you see compared with the past? Is the number increasing or decreasing?
- 7. If it is decreasing, since when and why?
- 8. Does the bird ever raid or disturb agricultural areas? If yes, when is the worst time?
- 9. Kind of crops attacked by cockatoo?
- 10. Kind of crops you plant?
- 11. When do you usually harvest, especially main crops?
- 12. What measures are taken to stop the birds raiding?
- 13. If the bird is caught, when is the usual time?
- 14. How do you catch them?
- 15. Is the catch done regularly? If yes, how many times a year. If no, when do you catch them?
- 16. What do you do with the catch? If you sell it, where do you sell it?
- 17. What is the price of each bird?
- 18. Are any resident professional bird catchers? If yes, where did they come from?
- 19. Do you agree with catching?
Additionally (for respondents who have seen cockatoo nests):
- 20. Where have you seen the nest?
- 21. What kind of tree is the nest located in height and location?
- 22. Have you seen the nest with eggs?
- Setiawan, I. - The Status of Cacatua sulphurea parvula in Nusa Penida, Bali, and Sumbawa, West Nusa Tenggara, Indonesia [Status Cacatua sulphurea parvula di Nusa Penida, Bali, dan Sumbawa, Nusa Tenggara Barat, Indonesia]. PHPA/BirdLife International, Bogor. Report No. 6., 1996