Christmas Island pipistrelle
|Christmas Island pipistrelle|
Pipistrellus tenuis murrayi
It is a small bat weighing around 3 to 4.5 grams. This species feeds on insects and roosts in tree hollows and decaying vegetation. It has sometimes been considered synonymous with Pipistrellus tenuis; however, revisions of the genus based on baculum have identified Pipistrellus murrayi as a distinct species. This is supported by genetic work conducted for the Australian Government as part of its investigation into the decline of Christmas Island ecology and the pipistrelle in mid-2009; the results of this analysis indicate that the Christmas Island Pipistrelle is closely related to but distinct from other Asian pipistrelles. Grave fears are held that the species may now be extinct, with the last individual bat seen in August 2009 with no further sightings despite intensive efforts to locate the species.
Decline and possible extinction
The Christmas Island pipistrelle has declined dramatically in the last two decades. It was once commonly seen throughout the island including in the settlement. It has disappeared from at least 80% of its range and declined more than 90% in abundance since 1994. A reassessment of the number of individuals remaining in January 2009 suggested there may have been as few as 20 individuals left. The only known communal roost contained only four individuals. Three years before there had been 54 individuals in this colony and there were several other known, similar-sized colonies. The long-term monitoring data suggested that, if the rate of decline continued, this species was likely to become extinct around mid-2009. Monitoring in early 2009 showed that some bats survived in the wild, prompting the Australian government to announce on 1 July 2009, that it would attempt to rescue the bat by bringing the last remaining individuals into captivity, with assistance of volunteer bat researchers from the Australasian Bat Society. In early August 2009 Australian Government gave permission to capture the bats to establish a captive breeding program. However, after four weeks of surveying located only a single bat through its echolocation. Researchers were unable to catch it and the last echolocation call of this bat was recorded on August 26, 2009, when it went silent. On 8 September 2009, the Australian Government announced that attempts to capture the bats had failed. No Christmas Island pipistrelles have been seen or heard since, and it is feared the species is now extinct. Due to its imperiled status, it is identified by the Alliance for Zero Extinction as a species in danger of imminent extinction.
Cause of decline
The cause of the Christmas Island pipistrelle's decline is unknown. Several potential threats have been suggested: predation or disturbance at roost sites, and disease. Introduced species such as the common wolf snake, giant centipede , yellow crazy ant, black rat or feral cats have all been identified as potential suspects responsible for the decline either through predation or disturbance of the bats. It has also been speculated that an unidentified health threat, or poisoning from the insecticide Fipronil used to control yellow crazy ant 'supercolonies' could be responsible for the decline.
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- MEDIA RELEASE The Hon Peter Garrett MP, Minister for the Environment, Heritage and the Arts,The Hon Warren Snowdon MP, Minister for Indigenous Health, Rural and Regional Health & Regional Services Delivery Member for Lingiari PG /301 1 July 2009 CHRISTMAS ISLAND ECOSYSTEM RESCUE 
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