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