Tuesday, 28 February 2017

The Yellow-crested or Lesser Sulphur-crested Cockatoo. Part 6. Captive Breeding

This is the 6th and final  of a series of articles on this once common but now critically-endangered species from the islands of Indonesia and of Timor Leste.


The quaint behaviour of the Avicultural Society, an organisation founded in U.K. in 1894, allows us to find very easily when a species was first bred in U.K. The Society gave a medal for the first breeding of a species and often a subspecies. In these more enlightened times a medal might be deserved for breeding an endangered species for a number of generations while keeping inbreeding to a minimum but I suppose the idea of a medal appealed to the many super-rich members in the aristocracy as well as the nouveau-rich industrialists and retailers who often had enormous collections of birds in their stately homes and who competed with one another to obtain the rarest birds from all over the world.

The first record of the Yellow-crested Cockatoo breeding in captivity in U.K. was reported in Avicultural Magazine in 1924. The breeder was M.T. Allen and the medal was given for breeding the subspecies C. sulphurea sulphurea. I have not seen the article.

By chance I do have copies of the Avicultural Magazine reporting the breeding in 1955 and 1956 of two other subspecies, namely, the Citron-crested (C. s. citrinocristata) and what was named as the Timor Cockatoo, C. s. parvula. The breeder in both cases was S.B. Kendall.

Dr Stanley Brian Kendall PhD MRCVS ARCS FIBiol (1915-1999) was a veterinary parasitologist then working at the Central Veterinary Laboratory in Weybridge, Surrey. Like many veterinary graduates of his day he worked in Africa as a Colonial Veterinary Officer for a time, in this case Tanganyika from 1943 to 1947. He lived in Chertsey, Surrey and joined the Avicultural Society in 1953.

By the 1950s the membership of the Avicultural Society was more mixed. There were still members of the aristocracy but the annual list shows zoo directors and curators, museum people, scientists and a great many private bird keepers and breeders. The tendency was for the latter not to be bird ‘fanciers’ who exhibit artificially selected birds competitively nor pet bird keepers. The Society was—and still is—a cut above those pursuits.

Kendall’s first article begins:

     The Citron-crested Cockatoo has always been a rare bird in captivity, presumably as a result of its limited distribution (Sumba Island), but during the temporary lifting of the ban [because of a risk of psittacosis to the public] on the importation of parrots in 1952-1953 a number reached this country. There are at present several odd males in different hands, but the hens are unfortunately very few.

He then went on to describe the simple outdoor aviary, the introduction of potential nest boxes, how the birds were fed and then the nesting and appearance of two young.

His second article is entitled, Breeding the Timor Cockatoo. And this is where I have trouble in knowing which of the currently recognised subspecies he actually bred. The candidates are, of course, parvula from Timor and occidentalis from the islands west of Timor, from Alor to Lombok.
The fact that they were clearly known in the early 1950s as Timor Cockatoos might suggest they were parvula. But this is what Kendall had to say:

     Timor Cockatoos are similar to the better-known Lesser Sulphur Cockatoo [sic]. from which they can be distinguished by the considerably less well developed areas of sulphur-yellow on the back of the head and cheek, and by the virtual absence of yellow on the chest and belly. In addition, they are markedly smaller; hens are often really tiny and must be the smallest cockatoo that exists.

I take this paragraph to indicate that C.s. sulphurea was sometimes imported from Sulawesi but again I have difficulty in deciding whether his birds were occidentalis or parvula, although the size might suggest parvula. But whether his birds really were parvula in the present definition I still doubt, especially since in another paragraph he wrote:

     As the popular name suggests, the main home of parvula is in Timor Island. Skins in the Natural History Museum, South Kensington, are labelled East Timor, South Flores, Pantar and Lombok…

In other words, the Museum was not recognising Hartert’s distinction between parvula and occidentalis.

I doubt we shall ever know the origin of Kendall’s birds that were imported into Britain in May 1952 unless, of course, somebody out there has records or photographs.

Kendall’s pair of cockatoos, treated in much the same way as his Citron-crested, produced two young.

As an example of coincidence I found while writing this article, Kendall’s medal from the Avicultural Society for breeding C. s. parvula for sale on eBay.

One  of S.B. Kendall's Avicultural Society Medals
for sale on eBay in Fenruary 2017

It was established that C. sulphurea could be bred—and would breed pretty easily. In part 2 of this series I mentioned Lindholm’s survey of parrots bred in American zoos between 1959 and 1994; 20 Yellow-crested Cockatoos were bred in 5 zoos; 50 Citron-crested in 11 zoos.

However, with all cockatoos, a major problem emerged: incompatibility of potential breeding pairs. In seemingly compatible pairs the male would kill the female without warning. Amongst a number of recommendations were that a number of cockatoos of the same species should be brought up together so that pairs could form naturally. However, other problems seemed to be associated with hand-rearing. Some cockatoos were taken from the nest and hand-reared. They, along with many other animals treated in such a manner, became totally confused as to their identity, living in some warped social structure between human and cockatoo. That problem has been exacerbated by the virtually complete hand-rearing of cockatoos from hatching in order to produce ‘tame’ (for a while) birds for the pet trade. These birds, imprinted on their human rearer and weaned onto adult food too soon, are simply but sadly crazy.

The Baby Cockatoo Industry

The industry—and it is an industry particularly in the U.S.A.—of production line, hand-reared birds for people besotted by baby cockatoos is a dead end as far as proper aviculture or captive breeding for conservation is concerned, and a life of confused misery for the individual cockatoo. Rosemary Low who is a world expert on parrots in captivity writes on her website:

     Can there be anyone who reads parrot magazines who is not aware of the fact that white cockatoos are too demanding to make suitable pets? That is putting it mildly.  Many, perhaps even the majority, of these highly intelligent and (when young) irresistibly appealing birds, end up as unwanted or abused. They develop serious psychological problems that manifest themselves in problem behaviours such as biting, screaming and feather plucking…
     …I already asked the question is there really anyone in the parrot world who does not know what is in store for most hand-reared white cockatoos?  Even ten or 20 years ago real parrot lovers were misguidedly hand-rearing these birds. Now that the problem is so well known, and parrot rescue facilities with sad, plucked and demented socially-deprived cockatoos are even seen on TV programmes, only the commercial breeder who cares more for money than for birds, continues to hand-rear them…
     The misery will end only decades after white cockatoo breeders shut up the nest-boxes forever. Even if that happened tomorrow, the supply of sad and abused birds to refuges would not dry up for another 50 years. Some people are dedicating their lives to repairing the damage that breeders have done. Cockatoo breeders: please take your heads out of the sand where they have been buried for at least a decade. The blame lies firmly on your doorstep. If you really love cockatoos you will stop breeding them now. And parrot owners, if you love them you will stop buying them from breeders. Only if there is no demand will the market dry up and the misery end.

Conservation Breeding

There is one saving grace for those who began an interest by having a pet cockatoo or other parrot. They have realised that many species have become endangered. Together with private aviculturists and those in zoos who seek to perfect proper captive breeding (i.e. without hand rearing) they provide a useful lobby to campaign and to raise money for conservation in the wild as well as ex situ.

Collar & Butchart of Birdlife International, in an excellent paper in International Zoo Yearbook in 2014 on captive breeding of birds for conservation include C. sulphurea in the ‘precautionary’ category. 

European Zoos have an EEP (European Endangered Species Programme) for the Citron-crested subspecies (C. s citrinocristata) but that does not include any of the equaly endangered Yellow-crested subspecies.

The European Zoos have produced guidelines for the husbandry of ‘white’ cockatoos in the various breeding programmes. However, the guidelines seem to me to place too much emphasis on artificial incubation of the eggs and hand rearing. Successful captive breeding (‘the discipline and practice of nurturing animals successfully through the reproductive cycle in captivity’ as defined by Collar & Butchart) is not achieved if eggs have to be incubated and/or chicks have to be fed by human hands. Parental care is part of the reproductive cycle. If the parents do not perform that task then captive breeding has failed even though chicks have been produced; the fault lies with the keeper who has not provided the correct conditions and needs to do more research and perhaps needs to spend a lot more money to get them right. 

In conclusion, given the relative ease of breeding C. sulphurea, as exemplified by Kendall in the 1950s, I have no doubt that given sufficient resources a successful captive breeding/reintroduction programme could be successful—but only as a last resort and only if the remaining habitat could support a population.


Finally, it is worth reading Dr Siti Nuramaliati Prijono’s* case study on C. sulphurea in Indonesia written in 2008 showing the state of the various populations up to 2005 and the conservation measures that were needed. It would be informative to have a follow-up study to see what has happened on the ground in the last ten years.

*Dr. Siti Nuramaliati Prijono has been Principal Secretary of the Indonesian Institute of Sciences since 2014. We were once near neighbours when she was working at the Scottish Agricultural College at Auchincruive.

Collar NJ, Butchart SHM. 2014. Conservation breeding and avian diversity: chances and challenges. International Zoo Yearbook 48, 7-28.

Kendall SB. 1955. Breeding the Citron-crested Cockatoo. Avicultural Magazine 61, 226-229.

Kendall SB. 1956. Breeding the Timor Cockatoo. Avicultural Magazine 62, 6-9.

Lindholm JH. 1999. An historical review of parrots bred in zoos in the USA. Avicultural Magazine 105, 145.

O’Brien J. 2007. EEP Husbandry Guidelines for Cacatua spp. 2nd edition.

Prijono, S. N. (2008). Case Study: Cacatua sulphurea. NDF Workshop. https://cites.org/sites/default/files/ndf_material/WG6-CS4.pdf

The Yellow-crested or Lesser Sulphur-crested Cockatoo. Part 5. Do the feral cockatoos in Hong Kong damage the environment?

This is the 5th of a series of articles on this once common but now critically-endangered species from the islands of Indonesia and of Timor Leste.

Introduced species cause immense damage in many parts of the world. But what about the feral cockatoos in Hong Kong?

Part of the two pages on the feral cockatoos in
A Photographic Guide to the Birds of Hong Kong

In a review of invasive birds in Hong Kong in relation to the clearance of the natural tropical evergreen forest before the 18th Century and the progressive restoration of the forests, Michael Leven and Richard Corlett (writing in 2004) considered the topic:

Of the species that have invaded Hong Kong in historical times, both Yellow-crested Cockatoos and Rose-ringed Parakeets cause temporary damage to trees in city parks by feeding on growing shoots (Herklots 1967 [reference only to parakeets]. The Yellow-crested Cockatoo also causes similar damage to native trees in secondary forest on Hong Kong Island and occasionally destroys crops of unripe fruits (T Corlett pers. obs.). These birds are not abundant enough for these impacts to be serious, but any future increase in parrot populations should be viewed with some concern. Perhaps more significantly, it has been suggested that these species may have been implicated in the disappearance of the native Great Barbet Megalaima virens from Hong Kong Island, presumably by competition for nesting holes (Carey et al. 2001). This can be excluded as an explanation in the case of Yellow-crested Cockatoo, as Great Barbets vanished from Hong Kong Island prior to the occurrence of the cockatoos, but the disappearance of the barbets did coincide with the period of peak abundance of the parakeets.

So the answer seems to be that their effect is negligible

Leven MR, Corlett RT. 2004. Invasive birds in Hong Kong, China. Ornithological Science 3, 43-55

Sunday, 26 February 2017

The Yellow-crested or Lesser Sulphur-crested Cockatoo. Part 4. Geographical Origins of the Feral Population in Hong Kong

This is the fourth of a series of articles on this once common but now critically-endangered species from the islands of Indonesia and of Timor Leste.

Can we deduce where the feral population of Yellow-crested Cockatoos in Hong Kong originated?

As I explained in Part 2 of this series, there are seven currently recognised subspecies of Cacatua sulphurea but since some of them are from small or relatively remote island groups which might not have been the easiest places to collect from I would argue we can narrow the possibles to four, viz:

C .s .sulphurea (Gmelin,1788) from Sulawesi
C .s. occidentalis Hartert 1898. Lesser Sunda islands from Lombok to Alor
C. s. parvula (Bonaparte, 1850. Timor
C .s. citrinocristata (Fraser, 1844). Sumba

Collar & Marsden (2014) have done a great job in both pulling together what is known on the subspecies and in making a statistical analysis of morphological characters. However, for my purposes I am relying on differences in the colour of the crest and on the depth and size of the patch of colour of the ear-coverts.

I do not know and do not know if anybody knows the genetics of these differences. Hybrids between Yellow-crested (of unstated lineage) and Citron-crested have been bred. I have found one photograph of such a bird which suggests that the colour of the crest tends towards yellow but have found no indication of what happens in later generations. However, it could be argued that if a citron-crested individual has been spotted in the past few decades amongst the feral birds of Hong Kong, then it is likely that citrinocristata has contributed genes.

In photographs of cockatoos in Hong Kong available on the internet and in photographs (taken in 2003-8) shown in A Photographic Guide to the Birds of Hong Kong, the occasional bird with an orange crest can be seen. Viney, Phillipps & Ying’s The Birds of Hong Kong and South China (8th edition, 2005) states that citrinocristata is present. However, the literature is confused: this source says citrinocristata was not introduced to Hong Kong. In passing it is worth mentioning that the IUCN Red List shows the species as a whole as having been introduced in Singapore with no mention of Hong Kong!

The Citron-crested is easy but what of the Yellow-crested? Viney, Phillipps & Ying (2005) state: Two races occur in HK: sulphurea [C. s. sulphurea] (yellow crest) and citronocristata… However, I am by no means sure that this is the case since none  of the birds we have seen, nor do any of the photographs I have been able to find, show the large deeper yellow ear-covert patch which appears characteristic of sulphurea. (There is also a stock photograph on Alamy which shows the deeper yellow patches of a bird photographed on Sulawesi.)

If we eliminate sulphurea as a major contributor to the present gene pool, that leaves occidentalis and parvula (once, remember, considered one and the same). The ear-covert patch of all the birds we saw in bird shops in the 1960s was relatively pale and the photographs of the feral birds show pale yellow patches. However, the patches do not seem sufficiently small to be parvula.

The photograph below is a greatly enlarged portion of a transparency of the female cockatoo we bought in Hong Kong. She was typical of all those we saw for sale then. Comparing the photographs of skins and the descriptions in Collar & Marsden (2014) leads me to suggest that the commonest form of the Yellow-crested cockatoo in the Hong Kong feral flock is occidentalis.

A greatly enlarged photograph of our female cockatoo in
Hong Kong in 1966 showing the pale yellow ear-covert patch

In terms of logistics in the 1960s and 70s, it could well have been easier to trap and transport cockatoos from Lombok (where they are no longer exist) and the chain of the Lesser Sundas extending east, including Sumba, to Jakarta or even Denpasar Airport (domestic flights in the 1960s) on Bali than to carry them on a fairly long sea passage from Sulawesi.

Determining from which island groups the Hong Kong flock is derived is not just of historic interest. Those conservationists considering reintroduction prefer to introduce the same subspecies as existed originally in the location. One those grounds they might reject the Hong Kong feral birds as a source (as suggested by Gibson & Yong, 2016). However, if they were the only source or if captive-bred birds of mixed origin were the only ones available, then I would be the first to say, introduce them and then let natural selection take its course (the outcome of which would be interesting). Better, surely, to have cockatoos of the same species on an island where they once existed than none at all.

Reflecting the birds being imported over the years, other species of cockatoo have escaped or been released, the commonest being the Tanimbar Corella (Cacatua goffiniana) which is hardly surprising given the numbers being traded in the 1970s. We saw a few Salmon-crested (Moluccan) Cockatoos (C. moluccensis) and White Cockatoos (C. alba) in the bird shops in the 1960s and the odd one has turned up in the wild. The Hong Kong Bird Watching Society also lists the Palm Cockatoo (Probosciger aterrimus) as an escapee.

The status of introduced cockatoos in Singapore in shown here, and in Taiwan by Lin & Lee (2006).

Collar NJ, Marsden SJ. 2014. The subspecies of Yellow-crested Cockatoo Cacatua sulphurea. Forktail 30, 23-27.

Gibson L, Yong DL. 2016. Saving two birds with one stone: solving the quandary of introduced, threatened species. Frontiers in Ecology and the Environment. DOI: 10.1002/fee.1449

Hong Kong Bird Watching Society. 2010. A Photographic Guide to the Birds of Hong Kong (revised edition). Hong Kog: Wan Li Book Co.

Lin RS, Lee P-F. 2006. Status of feral populations of exotic cockatoos (Genus Cacatua) in Taiwan. Taiwania 51, 188-194.

Viney C, Phillipps K, Ying LC. 2005. The Birds of Hong Kong and South China (8th edition). Hong Kong Government.

Thursday, 23 February 2017

The Yellow-crested or Lesser Sulphur-crested Cockatoo. Part 3. History of the Feral Population in Hong Kong

This is the third of a series of articles on this once common but now critically-endangered species from the islands of Indonesia and of Timor Leste.

The feral population of Yellow-crested Cockatoos in Hong Kong has recently hit the headlines. The population is healthier than any of those in their native islands of Indonesia and East Timor. A paper by Like Gibson of the University of Hong Kong and Ding Li Yong of the Australian National University* suggested that such feral populations could be used to repopulate habitats from which they have been extirpated or severely depleted. Science and the Hong Kong newspapers followed up the story. The latter though repeated the canard that the original founders of the introduced population may have been released in 1941 from an aviary at Government House or Flagstaff House just before the surrender to the Japanese.

Anybody with any knowledge of bird watching in Hong Kong in the early 1960s would be aware that the story is a load of old codswallop. Unfortunately, it is perpetuated by the standard book on Hong Kong birds, Birds of Hong Kong, by Clive Viney and Karen Phillipps. Thus my fourth edition (February 1988):

Detailed records have been kept since 1961 but the first introduction if this species is not known for certain. However, one story is that the original birds were released from Flagstaff House (where they were kept in an aviary) in 1941 just prior to the Japanese Occupation.

Virtually the same wording is in the 8th edition of 2005 (retitled The Birds of Hong Kong and South China).

It is not true to say that detailed records have been kept since 1961. The Hong Kong Bird Watching Society was formed in 1957 with a few but very enthusiastic and in some cases very experienced members, including a number with ready access to places like Victoria Barracks in which cockatoos were later seen. Sightings of unusual birds were reported and indeed the first sighting of an individual bird which had escaped was made in 1959.

A photograph I found in Amateur Photographer indicates that Yellow-crested Cockatoos were being imported and kept in Hong Kong in the 1950s:

Photograph by Kwok-Kwan Tam (Hong Kong)
Amateur Photographer 4 May 1955

It seems clear that the accidental introduction of Yellow-crested Cockatoos in sufficient numbers to form viable breeding flocks occurred during the 1960s when large numbers were being imported and kept in Hong Kong (see previous post on exports from Indonesia). It is not surprising that a number escaped, or kept as ‘homing’ birds, or simply released into the wild. Parrot stands, as opposed to secure cages, were popular and it is not difficult to imagine birds managing to escape from the short, light chains and rings that held them close to the perch. An example of one escaping—from a cage in this case—is on Gwulo here.

The story starts in the Hong Kong Bird Report for 1961. John (‘Jack’) Launcelot Cranmer-Byng reported under the heading ‘Escaped Birds’ and the sub-heading ‘Sulphur-crested Cockatoo’:

     There are at present several birds which have recently escaped from captivity. The most striking are the Sulphur-crested cockatoos. Early in 1959 one escaped from a private aviary and established itself in the Shouson Hill area, though it visited the University grounds several times in August and September of that year. It has been seen at intervals at Shouson Hill ever since, and it clearly thrives there. It has been observed on about twenty occasions and has been seen tearing the seeds out of fir cones as well as eating the shoots of a small bush while perched on the ground…While in flight the Cockatoo generally utters loud harsh cries. Its wing beats are laboured and hurried.
      In November 1961 two white Cockatoos were seen together in the Colonial Cemetery at Happy Valley. In January 1962 two Cockatoos were seen together in the University grounds on several occasions when they were observed cracking seeds in various trees. One was a large bird with a fine lemon-coloured crest, and a short length of chain dangling from one leg. This, however, did not appear to impede it in flight or when climbing about in the branches of trees. Its method of feeding was peculiar. It walked along branches very agilely and when it came to some seeds it would bend the twig over with its strong curved beak, hold it firmly with a claw and then proceed to crack the seeds one by one in its beak. The second Cockatoo was much smaller and although it had a small crest it did not appear to be lemon-coloured. 
     Since the bird at Shouson Hill (nicknamed Alexander for reference) does not sport a length of chain from his leg these two birds seen in the University grounds in January 1962 must be two further escapees. From records kept so far it would appear that an escaped cockatoo is quite capable of feeding itself on seeds and shoots and probably fruit, according to the season, while at large in the Colony. It would also seem that when the food supply is insufficient in one area it will fly to another part of the island where it will remain temporarily. No Cockatoos have been seen in the University area since the end of January 1962 though at the time of writing (end of April 1962) a pair have been reported regularly near the Central Government Offices and in the Colonial Cemetery. 
Any evidence of mating among escaped Cockatoos would be of considerable interest, as would any further information on their food supply and which other parts of the Colony they visit. Have they been observed in Kowloon or the New Territories? Have three Cockatoos been seen together at any time?

Jack Cranmer-Byng MC, MA (1919-1999) was Senior Lecturer in History at the University of Hong Kong and one of the two compilers of the 1961 Report. His Military Cross was awarded for gallantry at Arnhem in Operation Market Garden. His unit in the 250 (Airborne) Light Composite Company Royal Army Service Corps had the job not only of organising the supplies but also of defending the perimeter when necessary. The latter role at Arnhem was necessary. The history reads:

     …on the 20th September [1944], Captain Cranmer-Byng was ordered to take an RASC party under cover of darkness and to take over a sector of the perimeter at a point where there was danger of infiltration in the houses flanking the 4th Parachute Brigade position. This movement was successfully accomplished and the line was held, and at one time advanced, for four days in spite of heavy fighting and frequent attacks by mortar, self-propelled guns and single tanks.     Captain Cranmer-Byng was in command of the party throughout and was in much of heaviest fighting. On one occasion, despite a slight wound in the hand, he shot an enemy sniper dead. On another occasion he took a party of men out with a PIAT [Projector, Infantry, Anti Tank in army stores speak] and managed to drive off a self-propelled gun which was attacking the position at short range.     Subsequently, Captain Cranmer-Byng successfully disengaged his party, and led them down in the darkness through the enemy lines to cross the river to safety.     It was largely due to the inspiring leadership and coolness displayed by Captain Cranmer-Byng that the RASC sector held out against very considerable pressure, without food or sleep, and that the party was subsequently able to withdraw to safety when ordered to do so.

Cranmer-Byng was a stalwart of the Hong Kong Bird Watching Society and of the newly formed Hong Kong Branch of the Royal Asiatic Society. He left Hong Kong in 1964 to join the University of Toronto where he continued his interest in birds and the natural world into the 1990s. He died on 6 April 1999 in Canada.

In the 1960s, the University Compound and the hillside above was relatively undeveloped and was an important area for resident birds as well as a hotspot for migrants passing though Hong Kong. Cranmer-Byng reported on what he saw there (he lived in the same block of university flats as we did but we did not overlap).

Back to the cockatoos. From these early descriptions, it is not possible to determine if they were C.sulphurea or C. galerita. The smaller one noted in his report may have been Goffin’s Cockatoo (now called the Tanimbar Corella, Cacatua goffininiana). In the 1964 Report they were listed as C.galerita, again under ‘Escapes’:

This bird features in the 1961, 1962 and 1963 Reports as an escape. Records for 1964 indicate that two or three birds frequented Victoria Barracks from April to July, that two were in the neighbourhood of Sookunpoo in July, August and September, increasing to four seen regularly in that district to the end of the year. One was in the University area in early July. One appeared in May Road in October. One was seen at Ping Shan (the first NT’s [New Territories] record) on April 19 (Society Outing).

In an article in the same issue on birds seen on Broadwood Road, C. Dale reported that 3 or 4 cockatoos occasionally passed through with their raucous aggressive screeching.

The 1965 Report was similar in tone:

Two birds were seen together in 1961 and 1962, three in 1963 and now five in 1965, but there is still no evidence of breeding. The situation is now confused by a report that several of these birds are kept as pets and allowed to fly freely by day.

In the 1966 Report, an article on Birds of Government House Garden by Commander E.D. Webb R.N. (who lived in a flat in Government House) states:

…a flock of five Sulphur-crested Cockatoos, released for a fly-round each morning by a lady who lives near the Church Guest House [1 Upper Albert Road and just over the wall from Government House Garden; Han Suyin was once a resident].

By 1967, there were ‘at least six in the area of Victoria Barracks’ and there is a photograph of two of them taken by Major Rose.

We saw small groups of C. sulphurea flying in the Botanic Gardens/Victoria Barracks area (now Hong Kong Park) from late 1966 until we left in May 1968.

Botanic Gardens, Hong Kong ca 1966
Cokatoos were seen flying over and sometimes landingin the taller trees

By the early 1970s  the feral birds were being shown in reports as Lesser i.e. Yellow-crested Cockatoos (C. sulphurea) as opposed to the larger Australian C. galerita. Reported numbers increased: up to 8 in 1970-71, 13 seen together in 1972 (some Citron-crested) while 21 flew over the Ocean Terminal one evening; total population estimated at 30.

There is a curious statement in the 1973 Report to the effect that lemon crested were outnumbering the sulphur crested. Did the author mean citron-crested (C. s. citrinocristata)? 

By the 1970s it was strongly suspected that cockatoos were breeding in Hong Kong since the birds were seen in the vicinity of a suitable nesting hole. Finally in 1976 breeding was confirmed. On 27 March at Victoria Barracks (now Hong Kong Park), cockatoos were found nesting in a hole in a bombax tree 25 feet off the ground.

Since then the population has increased markedly and by the time we were back in Hong Kong in 1997, groups of cockatoos could be seen more or less anywhere in the north of Hong Kong island from Pokfulam in the west to Happy Valley in the west.

Regardless of whether anything comes of the suggestion of using the successful feral population to restock Indonesian islands, Hong Kong does present an opportunity to investigate experimentally the ecological factors that determine the size, structure and distribution of the population, studies that could not be done on the fragile populations in Indonesia and East Timor but which could provide useful, perhaps vital, information on the conservation and protection of native populations and their habitat.

My guess on the initial preference of escaped/released/homing cockatoos for Victoria Barracks, the Botanic Garden and the University Compound is that there were mature trees in those sites. Hong Kong in the 1960s was very different in terms of vegetation. The hills had been denuded of trees for use as firewood during the Japanese Occupation and it took decades for recovery to occur. A walk up Hatton Road to the Peak or along Conduit Path is an entirely different experience to that in, say, 1966.

Can we deduce from the appearance of the feral birds of the Hong Kong population anything about which part of Indonesia they came? That will be the subject of the next article in the series.

*Gibson L, Yong DL. 2016. Saving two birds with one stone: solving the quandary of introduced, threatened species. Frontiers in Ecology and the Environment. DOI: 10.1002/fee.1449

Additional material added 29 March 2017

Monday, 20 February 2017

The Yellow-crested or Lesser Sulphur-crested Cockatoo. Part 2. Population Crash and Conservation

This is the second of a series of articles on this once common but now critically-endangered species from the islands of Indonesia and of Timor Leste.

Given the distribution across the islands of eastern Indonesia and of Timor Leste, it is hardly surprising that morphologically distinct forms from the various islands have been catalogued. Some of the subspecies have been lumped or split and lumped again during the past 100 years or so. I am following Collar & Marsden (2014) who produced cogent statistical evidence for seven:

C .s .sulphurea (Gmelin,1788). Sulawesi (plus Muna and Butung)
C. s. abbotti (Oberhoiser, 1917). Masalembu islands in the Java Sea west of Wallace’s Line
C. s. djampeana Hartert, 1897. Tanahjampea and Tukangbesi islands
C .s. occidentalis Hartert 1898. Lesser Sunda islands from Lombok to Alor
C. s. parvula (Bonaparte, 1850. Timor
C .s. citrinocristata (Fraser, 1844). Sumba
C. s. paulandrewi Collar & Marsden, 2014. Tukangbesi islands

The following map from Collar and Marsden shows the distribution:

From Collar & Marsden 2014

However, there is plenty of scope for confusion as to which form was being studied in the wild, bred in captivity or photographed as I shall explain in a future article. One example will suffice here. Some authorities had lumped occidentalis into parvula on the grounds of a cline in bill size between Timor in the east and Lombok in the west. Collar & Marsden showed this argument to be erroneous and resurrected occidentalis by again splitting it from parvula. As a consequence, photographs labelled as C. s. parvula are shown on the internet but since they are labeled as having been taken on Komodo it is clear the photographer was following the taxonomy of White & Bruce (1986) who in their The birds of Wallacea (Sulawesi, the Moluccas and Lesser Sunda Islands, Indonesia): an annotated check-list (London: British Ornithologists’ Union) had lumped occidentalis into parvula.

The IUCN Red List states what has happened to the species: It has undergone a dramatic decline, which is still ongoing, particularly in the last quarter of the 20th century, such that it is now extinct on many islands and close to extinction on most others.

The Red List also states: Its precipitous decline is almost entirely attributable to unsustainable exploitation for internal and international trade. Illegal trapping continues in many areas… but then goes on to list other factors; large-scale logging; deforestation for agriculture; selective logging of large trees suitable for nesting; introduction of pesticides in 1889 (why ?); changes in agricultural crops; rainfall and, on Komodo and Rinca, predation by young dragons which are arboreal,

The Red List also mentions the fact that the birds were regarded as a pest by farmers and I either read or was told when we were in Hong Kong in the 1960s that marauding cockatoos on farm land were killed if they could not, preferably, be captured for trade.

It seems to me that the C.sulphurea population was caught by a perfect storm. Indonesia became known as the epicentre of the wild bird trade. The domestic market in Java and Sumatra for cage birds was, and still is, not only enormous but growing; the human population has increased from 88 million in 1960 to 264 million. In addition there was, and again still is, international trade (not all of it one way) largely via Singapore and Hong Kong. CITES and local protection measures are known to have had an effect in allowing some recovery of the cockatoo population on Sumba but while there is undoubtedly some illegal trapping still going on, local populations appear, in general, not to have bounced back but continued their decline. That is where the other factors that caused and maintain the loss come in: the removal of large trees suitable for nesting; clearance and fragmentation of forests for agriculture; a change from growing maize and papayas to crops unsuitable for cockatoos.

CITES per se was insufficient to provide protection. In a racket in which the Solomon Islands became central, birds trapped illegally in Indonesia and New Guinea were shipped to the Solomons and then entered trade as 'captive bred' in numbers that were blatantly impossible. This bird and mammal and reptile laundering resulted in 800 allegedly but clearly impossibly captive-bred Yellow-crested Cockatoos being exported from the Solomons between 2002 and 2004. TRAFFIC traced the trade through Malaysia and Singapore dealers to Taiwan.

One factor not considered by any of those seeking the reasons for the upsurge in trade in C. sulphurea in the 1960s and 1970s was I suspect an unintended consequence of a conservation measure taken by another country in 1960.  In that year Australia banned the export all all wildlife and that ban included, of course, those stalwarts of the pet bird trade, the Greater Sulphur-crested Cockatoo (Cacatua galerita) and the corellas. The demand for cockatoos in an unregulated trade turned entirely to Indonesia and what was then Portuguese Timor.

In the mid-1960s Indonesia was in a political and economic mess under the Sukarno regime. However, there is an interesting claim in Joseph H. Lindholm's historical review of parrots bred in zoos in the U.S.A:

Another influence was the change in Indonesian export policies following the overthrow of the Sukarno government in 1965. Prior to this, export of wildlife appears to have been strictly regulated. For example, San Diego Zoo was allowed to import only two pairs of Rothschild's Mynahs Leucopsar rothschildi under special permit in 1961 [references given].  However, by the end of the decade hundreds of these birds were being exported each year. Apparently, the infamous President Sukarno held a personal aversion to the animal trade (Ryhiner and Mannix, 1958). In the mid and late 1960s, large numbers of Lesser Sunda and Moluccan parrots entered the international market and a number of these were bred in American zoos at this time.

The rapid decline of the cockatoo has not, of course, been ignored. lndonesian and international conservation bodies are co-operating to monitor the populations and to enact practical local protection measures as well as to recruit villagers and schoolchildren as guardians of the cockatoos and their nesting sites. All is not gloom and doom. According to the World Parrot Trust website, Komodo National Park (which includes both Komodo and Rinca), held 695 cockatoos in 2015, up from 558 in 2010.

Cahill AJ, Walker JS, Marsden SJ. 2006. Recovery within a population of the critically endangered citron-crested cockatoo Cacatua sulphurea citrinocristata in Indonesia after 10 years of international trade control. Oryx 40 1-7.

Collar NJ, Marsden SJ. 2014. The subspecies of Yellow-crested Cockatoo Cacatua sulphurea. Forktail 30, 23-27.

Lindholm JH. 1999. An historical review of parrots bred in zoos in the USA. Avicultural Magazine 105, 145.

Nash SV. 1993. Sold for a song…The trade in southeast asian non-CITES birds. Cambridge: TRAFFIC International.

Shepherd CR, Stengel CJ, Nijman V. 2012. The Export and Re-export of CITES-listed Birds from the Solomon Islands. TRAFFIC Southeast Asia, Petaling Jaya, Selangor, Malaysia.

Revised 24 February 2017

Saturday, 18 February 2017

The Yellow-crested or Lesser Sulphur-crested Cockatoo. Part 1. Two birds in 1960s Hong Kong

This is the first of a series of articles on this once common but now critically-endangered species from the islands of Indonesia east of Wallace’s Line and of Timor Leste.

We had hoped to see a particular species of bird on an expedition cruise last September through the Lesser Sunda islands of East Timor and Indonesia. Although not a birding trip we could have been lucky, particularly on Rinca and Komodo, and seen what is now called by the nitwits who try to impose a common name, the Yellow-crested Cockatoo (Cacatua sulphurea) but which was always known as the Lesser Sulphur-crested Cockatoo*. But we did not see one, nor hear one either because the cry, once heard, is never forgotten.

We have found it difficult to believe that C. sulphurea has become critically endangered. They were once so common that in the 1960s they arrived for the pet and avicultural trade in Hong Kong in batches of tens if not hundreds for many months each year—and we learnt by experience that parrots are totally, completely and absolutely unsuitable as pets.

In the 1960s the birds shops of Hong Kong had not been brought together to form a bird market. Li Yuen Street East (but it may have been West) right in Central had a bird shop and shortly after our arrival we saw a single cockatoo housed in a standard parrot cage. He (it is easy to sex this species—the males have black eyes, the females hazel-brown to red) sat calmly alone in a cage. The price even without haggling was ludicrously cheap and soon he was sitting on the balcony of our flat overlooking the university compound. Given the full name of Polly-Ethylene and the short name of Polythene, he was a Citron-crested Cockatoo from Sumba, then as now considered a sub-species of the Yellow-crested Cockatoo (C.s.citrinocristata). His crest was not yellow but a fetching shade of apricot orange.

Polythene. Male Citron-crested Cockatoo on our balcony in Hong Kong.
Photograph taken very shortly after his arrival--hence the frayed feathers
and the scruffy appearance

Polythene, judging by his beak and legs, appeared to be an older bird. He must have been in captivity for some time because he had a ring and broken swivel on one leg which after a few weeks we removed with the aid of a large towel, heavy gauntlets and two pairs of pliers. At first, when approached, he would shuffle to the furthest point on his perch and slightly open his beak. Over a period of months my wife persuaded him to move slowly along the perch towards her and eventually to put his head down for a scratch around the crest. But he would only do this if there were no human males in the vicinity.

A few weeks later there was a small batch of cockatoos in the bird shop and another, this time a female with a yellow crest, was installed in the flat. Immediately, we had a mystery. This new, lively and apparently tame bird started to speak—in a broad Australian accent. She constantly informed the world to ‘git out of the way’. There was only one name for her: Didgeridoo. But how did this apparently young bird hatched in Indonesia come to speak Australian English? Did she learn it in Indonesia from Aussies living there or was she returned to the bird shop by an Australian family leaving Hong Kong and then put in with a batch of newly imported birds?

Didgeridoo. Female Yellow-crested Cockatoo (probably C.s.occidentalis)
enjoying a shower while hanging over Conduit Road in Hong Kong

We were lucky. A colleague, hearing of the batch of birds at the shop, bought one of the others. It seemed healthy but after a few days developed all the signs of psittacosis and died.

Didgeridoo was so tame that every evening she would fly between us the whole length of the flat time after time, landing on an outstretched arm with a whoop and a bow. That went on for many weeks until one night when I was wearing a white shirt she flew and attacked me with beak and claws. That was the end of her flights from arm to arm because if she saw me while she was free in the flat, her pupils would narrow and she would then launch herself at me. During these sessions I retreated to the balcony but if she saw me through the window she would try to get at me through the glass. Her antipathy developed further to the extent that if I gave her a choice morsel of food by hand she preferred to nip my finger than take the food. Being given a sharp nip by a cockatoo of any size is not a pleasant experience.

Both birds were fond of fruit cake as a treat (aren’t we all). My grandparents were married in 1916 and for their Golden Wedding had a cake made and iced by the locally renowned Mrs Edwards. My grandmother put a piece in a small box and took it to the post office to send to Hong Kong. Unfortunately, she sent it by surface mail as an aerogramme from my father explained. After six weeks or so on board a ship travelling through the tropics the box of cake appeared. My expectations were shattered by the discovery of a very large and fat live grub in the middle of the piece of cake. Risking a nip I offered the cake, grub and all, to Didgeridoo. She took it, carefully extracted the grub, and then discarded the remains of the cake while eating the grub with great relish. We never told my grandmother.

Shortly afterwards, we moved flat. During the day the cockatoos were put out on a narrow balcony overlooking Conduit Road at 1st floor level. Didgeridoo in particular took a great interest in passers by while keeping a wary eye on Black Kites overhead. The cheery man who sorted and collected rubbish each day was greeted by a squawk even though his appearance changed according to the clothes acquired from his gleanings. For the final few weeks we lived there he greeted all the amahs sporting my old deerstalker which the moths had been attacking with some vigour.

Cockatoos are noisy—very noisy, particularly at dusk and dawn but our two at the time were relatively quiet until they caught first sight of us walking from the University along Conduit Road. Then all hell broke loose until we were inside the flat, had greeted them and they had had their daily  shower from the laundry spay. Extra showers at weekend or even from heavy tropical rain beating in were their idea of heaven.

Over the two years, Polythene had become more friendly with Didgeridoo although he still kept his distance. When it was time to leave we decided to fly them back to UK a couple of weeks before leaving ourselves. The metal work shops in the area west of Hollywood Road would make anything and we soon had a travelling case to our own design. The day of departure started with thick towels and gauntlets and then a taxi to the Star Ferry. Carrying large parcels was not allowed in 1st class and so we had to go down the ramp to the bottom deck. The ramp was fairly crowded with coolies and without prompting, came the very loud cry ‘Git out of the way’. It certainly parted the crowds but could have been even more effective had she learnt to do it in Cantonese as well as Australian.

Then it was to the Agriculture Department for a veterinary certificate and on to Kai Tak and the B.O.A.C. cargo office. We even went up the the public gallery to see the plane take off.

In the meantime my father had acquired two parrot cages and he and Vic set off for Heathrow to collect the birds from the handling agents after clearance through customs. Within a few months we moved them to the freezing cold of Cambridgeshire. They now seemed friendly enough to live in the same cage and using the hardwood from the packing cases in which furniture had been shipped back to UK and some very strong weld-mesh netting I made a large cage. They started to snuggle up to one another and life together seemed to be going well. They had to put up with the dog who was inquisitive. A yelp and a sore muzzle suggested one of them had seen her off but a yelp some weeks later was followed by something more serious. The dog reacted badly; her skin erupted in urticaria and for several hours we worried we might see full anaphylactic shock. After several hours the bumps and itchiness started to subside and she never went near the cockatoos again.

But then number one son started to toddle. The proximity of cockatoo beaks and very small prying fingers is something best avoided and so my father converted an old aviary into a palatial cockatooery—not an easy job since conventional wood and wire and soon reduced to shreds. All seemed to be going well when one morning the male attacked the female and killed her in seconds. Around that time in the early 1970s, males killing females was becoming recognised as one of the main problems in keeping seemingly compatible pairs of cockatoos.

Rather than leave Polythene on his own, we moved him to a zoo where he lived in his cage surrounded by other birds and mammals keeping his old habits of retreating in the presence of men but coming forward for a scratch from the human females he knew or got to know. He died suddenly a couple of years later. He always had the appearance of an old bird but how old he was we had no way of finding out.

We were completely cured of the notion of keeping cockatoos or any of the large parrots other than for necessary captive-breeding projects. The later antics of private parrot breeders in producing hand-reared, imprinted parrots purely intended as household pets for the parrot-obsessed reinforced that view.

What we did not know in the 1960s was what the effects of collection and habitat loss would be on this species nor of its colonisation of Hong Kong—two topics for future articles.

*The name, Yellow-crested Cockatoo, is particularly crass. The older Lesser Sulphur-crested Cockatoo at least reflects its specific name sulphurea (Gmelin, 1788). The Greater Sulphur-crested Cockatoo is now called simply the Sulphur-crested Cockatoo but has the scientific name Cacatua galerita (Latham, 1790).

Thursday, 9 February 2017

Viral Nightmares

I have been suffering from a virus and one of the effects has been nightmares. This nightmare morning was typical even though it did not involve wandering round a vast hotel trying to remember the room number or successively losing three cameras in the loose rigging of a boat driving through the streets:

The Times was again pushing without comment or criticism some publicity-seeking American medic’s book on diet and health. I hurled it across the room. I started to read a scientific papers online but after seeing two with the phrases ‘in animals and humans’ and ‘by using the zebrafish as the model’, I pushed the mouse away in disgust. Then came the lunchtime BBC news with its emoting newsreaders and reporters being even more gut-crunchingly sickbaggy than usual. Cushions were hurled at the television. But I was running out of ammunition and the Scottish news (known for inducing seething rage) had not even started. Some so-called American businessman was reported as saying something stupid on something called Twitter (now apparently the main source of news stories for the BBC). Desperate times. I couldn’t find the remote control and had no cushions left. I lurched from the chair to find that I was awake. My morning had been only too real.