Seychelles Sheath-tailed bat: a forgotten species?
Occurring only in the Seychelles, the Sheath-tailed bat (Coleura seychellensis) is the rarest bat species, and one of the rarest mammals in the world.
A robust nation-wide census was undertaken in March 2013, during which only 61 individuals were recorded. These 61 individuals are split between three caves on Mahé and one solitary cave system on Silhouette. The Silhouette roost contains a maximum count of 31 individuals, making it a relatively important stronghold for the species. Professor Paul Racey of the University of Aberdeen and International Union for the Conservation of Nature (IUCN) conducted the census this spring.
This small, insectivorous bat has experienced a rapid historical decline caused by multiple factors that includes disturbance from humans and introduced predators such as cats and rats. Anecdotal evidence suggests the species was once quite visible across the larger granitic islands. Today however, few young Seychellois have set eyes upon the species - known locally as “Sousouri Bannan” - and worryingly, many people may be unaware of its fragile existence. The Sheath-tailed bat is becoming a ‘forgotten species’ among the national population - out of sight, out of mind.
Coleura seychellensis currently enjoys no legal protection in the Seychelles, and thus needs all the attention it can get. The conservation community continues to face a tricky task in facilitating its recovery. On Silhouette, the roost is conserved by the Island Conservation Society (ICS). A placement student from the University of Manchester, Rachel Kwok, recently completed a project with ICS, investigating the flight range, foraging behaviour and emergence and retirement times of the Silhouette population. Results indicate that bats can be seen (or detected using an electrical bat detector) foraging over the La Passe marsh, in the early morning (between an hour and half-an-hour before sunrise) and in the early evening (during a 40-minute period following sunset). This work has identified viewing windows for ecotourism; and some island visitors have accompanied the ICS team to catch an exciting glimpse of these mammals foraging over the marshland.
This small, insectivorous bat has experienced a rapid historical decline caused by multiple factors that includes disturbance from humans and introduced predators such as cats and rats. Anecdotal evidence suggests the species was once quite visible across the larger granitic islands. Today however, few young Seychellois have set eyes upon the species - known locally as “Sousouri Bannan” - and worryingly, many people may be unaware of its fragile existence. The Sheath-tailed bat is becoming a ‘forgotten species’ among the national population - out of sight, out of mind.
Coleura seychellensis currently enjoys no legal protection in the Seychelles, and thus needs all the attention it can get. The conservation community continues to face a tricky task in facilitating its recovery. On Silhouette, the roost is conserved by the Island Conservation Society (ICS). A placement student from the University of Manchester, Rachel Kwok, recently completed a project with ICS, investigating the flight range, foraging behaviour and emergence and retirement times of the Silhouette population. Results indicate that bats can be seen (or detected using an electrical bat detector) foraging over the La Passe marsh, in the early morning (between an hour and half-an-hour before sunrise) and in the early evening (during a 40-minute period following sunset). This work has identified viewing windows for ecotourism; and some island visitors have accompanied the ICS team to catch an exciting glimpse of these mammals foraging over the marshland.
The organisation currently has funding proposals pending with the Global Environment Facility and Bat Conservation International for a project aiming to offer community outreach, education, and awareness-raising activities for the bat on Silhouette. This will include the installation of video camera and audio equipment in the cave, allowing visitors to observe a live feed on television screens. It will also allow continuous surveillance, possibly enhancing existing knowledge of the species’ mating behaviour. In the meantime, recent footage taken from inside the cave can be seen on youtube at http://youtu.be/BIqd4YXZgg8
The Sheath-tailed bat should be among Seychelles’ best-known species alongside the coco-de-mer, giant tortoise, and of course, its larger cousin the giant fruit bat. It is more endangered than the Paradise Flycatcher, Black Parrot, and virtually every other mammal species worldwide, and reversing its decline will require a collective national effort.
If you have any information about Sousouri Bannan we would be delighted to hear from you. Perhaps you used to see it regularly many years or know the location of old roost sites (caves where the species used to live). Please contact Island Conservation Society (Silhouette) on 4321016 or 2714488, or email us at silhouette@ics.sc
Benjamin Thompson
Conservation Officer, Island Conservation Society
Forrás: www.nation.sc