22 August-5 September 2009
Location: Christmas Island
Perth Zoo Field Workers: Helen Robertson (Animal Health and Research Director); Simone Vitali (Senior Veterinarian) and Meagan McPharlin (Acting Australian Fauna Supervisor)
Rough terrain in which the field work was completed.
About Christmas Island
Christmas Island is located off the coast of Java, Indonesia. It has been an external territory of the Australian Commonwealth since 1958. With its tropical climate, the temperature is 27–29°C during the day and 24°C at night, all year round.
The majority of the island is a national park yet habitat destruction due to mining and other human activities, introduced species and unregulated water extraction have resulted in an ecological shift that has seen several species become extinct.
Background to the Project
A dramatic fall in native reptile numbers has occurred on Christmas Island. Five endemic species – Lister’s Gecko, the Blue-tailed Skink, the Forest Skink, the Giant Gecko and the Christmas Island Blind Snake – are found on the island. They compete for food and shelter with five introduced species: the Asian House Gecko, Barking House Gecko, Grass Skink, Flowerpot Blind Snake and Asian Wolf Snake.
Blue-tailed Skink.
Blue-tailed Skinks (Cryptoblepharus egeriae) and Forest Skinks (Emoia nativitatus) were once commonly found across the island, however, both are now restricted to the south-western corner (Egeria Point). Blue-tailed Skinks have gone from being one of the most conspicuous and abundant reptiles on the island to being only found in very few locations and in small numbers. Similarly, Forest Skinks were also common in the western half of the island as recently as 1979 but now it is difficult to find more than one in each survey attempt.
This dire state prompted the Federal Government to initiate a captive insurance program to ensure the survival of these two species. Perth Zoo was approached because of its experience and success in breeding Lancelin Island Skinks for release. In conjunction with the Department of Environment and Conservation, 152 of the critically endangered skinks were bred at the Zoo and released onto Favourite Island. The program is considered a success.
With this background knowledge, Perth Zoo staff travelled to Christmas Island in August and September to work with national park staff to collect the first founder animals for the skink insurance programs. They also helped draft husbandry manuals for the skinks’ care.
Goals
Meagan and Helen collect data.
The first goal was to locate the two skink species and then collect 40 of each species. Due to the fall of numbers in the wild, insurance populations need to be established both on and off the island. One is to be established at Perth Zoo at a later date. This means the Perth Zoo population is kept separate from any unidentified factors such as environmental change or disease that may be contributing to the skinks’ decline on the island.
Later, the skinks will form part of a breed-for-release program. At the moment, however, the focus is on establishing insurance populations, researching the skinks’ biology and investigating and addressing threatening processes.
Process
Simone and Helen complete health checks on skinks.
One day Simone and Helen focused on the Blue-tailed Skink while I (Meagan) tried to locate Forest Skinks. I found two previously unknown locations on pinnacle rocks, a skink favourite because of their hollow, labyrinth-like nature which give them plenty of places to hide.
We collected the skinks into carry packs containing soil and leaf litter in which they could hide. At the end of the day we trekked back to the vehicle then drove back to base camp with the skinks.
All of the skinks were weighed, measured and checked for any physical abnormalities. Faecal samples were taken, if possible, to be later checked for parasites. All skinks collected so far appear to be in excellent health.
For now skinks are being kept in enclosures inside a modified gazebo on Christmas Island until a long-term option can be established. Here the animals are exposed to natural sunlight and the very humid, local climate. We also gave the Forest Skinks artificial labyrinths to replicate their complex habitat within pinnacle rocks.
During our trip we collected 17 Blue-tailed Skinks and one Forest Skink. Since returning to Perth Zoo, Christmas Island staff have collected a further 21 Blue-tailed Skinks and another Forest Skink. Finding so few Forest Skinks is of concern.
Forest Skink.
Highlights
I work very closely with reptiles at Perth Zoo so working with skinks in the wild was very rewarding. I was very excited when I found the two new locations for the Forest Skinks. I approached the challenge with the mentality of ‘If I was a skink, where would I be?’
Challenges
The skinks are usually found in habitats with very rough terrain – pandanus vegetation with sharp pinnacle rock cliffs with a drop into the sea on one side. Pandanus has serrated leaves, which means I had to tend to leg and arm scratches more than once. Also, the humidity meant that wherever we went we had to carry plenty of water and my clothes clung to me.
Benefits
Temporary sheltered facility to house the skinks.
I value being involved with in situ conservation, and providing knowledge and experience that will improve the success of the program. Contributing to the initial stages of planning, brainstorming and implementation meant I developed problem solving skills and applied the knowledge I’ve learnt at Perth Zoo to the wild. The husbandry for the skinks was developed using our knowledge of similar species because so little is known about the ecology of Christmas Island skinks. This meant a huge learning curve but I love learning new things.
Working with Helen and Simone, who are professionals with such calibre, and being able to learn from their vast experience was also rewarding. I enjoyed the sensory overload: being in a new place, meeting new people, adjusting to new animals and the challenges of trekking through the habitat and adjusting to the climate.
