Tropical Natural History 11(1): 75-80, April 2011 2011 by Chulalongkorn University Short Note Current Status of the Milky Stork Captive Breeding Program in Zoo Negara and its Importance to the Stork Population in Malaysia AHMAD ISMAIL1*, FAID RAHMAN1, DOREEN KHOO SAY KIN2, MAT NAIM HAJI RAMLI2 AND MOHAMMAD NGAH2 1Department of Biology, Faculty of Science, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor Darul Ehsan, MALAYSIA 2Zoo Negara Malaysia, Jalan Ulu Kelang, 68000 Ampang, Selangor Darul Ehsan, MALAYSIA * Corresponding author. E-mail: [email protected] Received: 11 June 2010; Accepted: 7 January 2011 The Milky Stork, Mycteria cineria breeding and reintroduction program. With Raffles 1822 (Circoniformes: Circoniidae), the support from both government and non- can be found in restricted parts of Southeast government agencies (i.e. PERHILITAN, Asia, being principally in Cambodia, Malaysian Zoological Society, Zoo Negara, Malaysia and throughout Indonesia, with Malaysian Nature Society, etc.) the first vagrant status in Vietnam and Thailand. actual captive breeding and reintroduction Within Malaysia it has the status of rare to program was done between 1998 and 2004 local resident in the Peninsular Malaysia1. in Kuala Selangor Nature Park. The effort Around 50-70 years ago Milky Storks could however had failed due to several problems be found scattered in Peninsula Malaysia and constrains as highlighted by Malaysian from the coasts of Kedah, Perak, Selangor, Nature Society8. The program continues Malacca and Penang2,3, whilst in East today in Kuala Gula, Perak. Before such Malaysia they were also reported to have initiative was taken, the captive breeding existed with the status of rare and much program in Zoo Negara was given less localized4. However, the global Milky Stork priority in solving the Milky Stork issue. population has undergone a rapid population Successful individuals hatched and reared decline with a current estimated population were mainly for the purpose of of 5500 individuals (minimum) remaining multiplication, exhibition and exchange worldwide5. In Malaysia Milky Stork exercise between zoos. Therefore, not until populations have declined more than 90% sometimes after the first reintroduction in over the last 20 years6, from over 100 Kuala Selangor does Zoo Negara focus on individuals in 1984 to 10 in 2005 and less the captive breeding for conservation than five individuals being observed purposes. Regardless, captive breeding is recently in Pulau Kelumpang and Pulau viewed as one of the important components Terung7, the last known Milky Stork in the project and, therefore, its contribution habitats in the Matang Mangrove Forest, and the future of Milky Stork breeding Perak, Malaysia. programs in the Zoo Negara should be The Malaysian government has the evaluated and highlighted. intention to increase the Milky Stork This paper aims to analyse and report the numbers and to this end several actions have Milky Stork breeding program in Zoo been taken, such as a Milky Stork captive Negara and its success. Data on Milky 76 TROPICAL NATURAL HISTORY. 11(1), APRIL 2011 FIGURE 1. Successful egg hatch (total numbers) for the Milky Stork in captivity from 1987 to 2005. Storks in Zoo Negara were obtained from in subsequent years from San Diego Zoo available records kept at Zoo Negara, and Rotterdam Zoo. The first successful updated until the year 2005. Besides the nesting was recorded in 19879 when two hatching records, information from the Zoo pairs of three-year-old birds nested and one Keeper and literature related to Milky pair hatched two clutches of two chicks and Storks in Zoo Negara were also analysed. the surviving chicks later continued to Based on the breeding activity of Milky breed. Records from Zoo Negara give more Storks in captivity, the captive population of insight with four males and four females Milky Storks can be increased by captive Milky Storks successfully producing 19 breeding if proper planning is executed, but chicks within 2 years since 1990. However, data on the successful reintroduction of the according to previous records and species back to the wild is absent. We also observations by the Zoo-keeper, not all the highlight the potential important of this chicks survived. Only 48% of the chicks captive breeding program in repopulating reached their adulthood and continues to wild Milky Stork population, the threats that breed. Most deaths occurred as the result of the released captives might face and the swollen joints and leg deformities. need of specific studies to improve the Malnutrition due to unbalance diet given current attempts at the conservation of may have been the possible cause for this. Milky Storks in Malaysia. Other reasons included nest disturbance or The first five males and five females in collapse of the nest tree structure that Zoo Negara were obtained from Singapore caused the eggs or chicks to be dumped to and Johor Zoo in 1987. Six more adults, the ground, incorrect chick feeding and the with at least three females were introduced weakening of pair bonds due to egg ISMAIL ET AL. — CURRENT STATUS OF MILKY STORK CAPTIVE BREEDING 77 manipulation and artificial egg incubation their own record on date of hatch, early period. Another aspect that is important is growth rates and health. This information is inbreeding. Genetic studies including very important for further breeding and molecular sexing studies on Milky Stork reintroduce programme. Nevertheless, the were carried out recently but the results on past experience of the last 23 years of inbreeding are still under investigation10,11. breeding captive Milky storks in Zoo Figure 1 summarizes the available Negara has led to improved handling records of yearly total for Milky Stork eggs methods and artificial nest support hatched in captivity in Zoo Negara. Since construction, chick rearing methods and so 1987, 10 individuals were reared in a cage on giving a great aid to future captive of 30 m x 30 m x 14 m and from these the breeding programs here or elsewhere. captive population has increased to more The Milky Stork captive breeding than 100 individuals beyond 2005. During program aims to re-establish the lost the first 10 to 20 years in captivity, the poor population of Milky Storks in Malaysia by documentation on bird growth, survival and re-introducing the captives into a new improper labelling means the detailed environment. This then requires a suitable information on the breeding success is not location capable of supporting the released available. This poor documentation was birds in terms of shelter, food, breeding probably due to early function of Zoo grounds, low parasite, predator risks and Negara as an exhibition and education other threats. Many of these aspects can be centre. Only recently has Zoo Negara suitably met and controlled in specific become more active in education, research conservation sites. Matang Mangrove Forest and conservation. Moreover, with the is one of the proposed ideal sites for the limited cage size and available space in Zoo release program in Peninsular Malaysia. Negara, the excess numbers of Milky Storks Further study, however, is needed to address were used in exchange programs with both the importance of managing and conserving local and international zoos as part of a specific habitats that play an important role conservation program. A total of 47 Milky for these birds. In the meantime, Zoo Stork individuals were produced between Negara will play a role as the main Milky 1990 and 1996 with minimum of 3 and Stork supplier for this program to meet its maximum of 9 successfully hatching chicks objectives. With the current population each year. However, no data for the number trend, (high number of breeding adult birds of chicks that hatched from 1997 to 1999 aged 5 years and above) the number of inclusive is available. The birds were Milky Storks in Zoo Negara is expected to probably left to breed in the cage and increase within the next few years. As the records were not made during this period. Zoo Negara supply the Milky Storks, it The years 2002 and 2005 show the two should maintain a healthy number of the highest numbers of chicks hatched at 22 and birds in its possession. However, these are 17 respectively, with a total of 39 fairly considerably genetic bottlenecked and individuals recorded. Breeding activity was inbred and so new out bred breeding stock reported to continue until the present day should be introduced and introgressed into and proper records have been kept as a these stocks at the zoo as soon as possible priority only after 2005. Every birds hatched and then expanded from there. in Zoo Negara will be marked and have 78 TROPICAL NATURAL HISTORY. 11(1), APRIL 2011 From what we have discussed, based on with the widespread destruction of the increased number of birds, Milky Storks mangrove forests, especially in Asia22-24. can be successfully bred in captivity, even Milky Stork populations have thus though with minimal effort as shown in Zoo indirectly been threatened by the Negara during the early period. In contrast, uncontrolled expansion of the aquaculture the significant decrease in the wild industry. Therefore, responsible authorities population size and distribution patterns of should continuously monitor Malaysia’s Milky Storks since 1989 suggests not only coastal activities. that habitat protection alone is not sufficient Other threats to introduced populations, and a reintroduction from captive stock is as per wild birds, would include poaching of likely to be required. In contrast to the eggs or adults, disease, predation, decline in wild populations, the number of hybridisation with other stork species, captive breeding individuals in Zoo Negara inability to correctly hold and defend has increased from 10 to more than 100 breeding territory or hunt for food individuals in 2005. We therefore conclude (following captive breeding) and that not only it is possible to breed Milky susceptibility to disease or poor mating Storks in captivity, but that the decline in characteristics and low fecundity associated wild Milky Stork populations is attributed to with inbreeding and low genetic variability.