Homes for otters, bats and birds have sprung up all over Pulau Ubin, in an effort to boost numbers of the endangered creatures which cannot be found on the mainland.

Building on its success from bringing the hornbill back from the brink of extinction with the help of nesting boxes, the National Parks Board (NParks) has worked with student volunteers to build bat roosts and otter holts, for example.

Over the past two months, efforts to preserve Pulau Ubin's unique biodiversity in this way have expanded, NParks said yesterday.

Last month, works were completed on a new sensory trail pond, made up of four former fish farming ponds combined to provide habitats for wildlife.

Students from Ngee Ann Polytechnic helped introduce plants that would attract herons and kingfishers, as well as fallen trees that the birds could use as perches.

NParks worked with students from various schools on its conservation efforts, including Republic Polytechnic and ITE College East.

The institutions' students helped design and build bat roosting boxes for the mammals - which can help keep insect populations in check and pollinate plants. There are currently 30 such boxes across the island.

Pulau Ubin is home to several species of animals which are not found on mainland Singapore, some of which are endangered. These include the oriental small-clawed otter, the world's smallest otter and a different species from the smooth-coated otter often spotted here.

Two otter holts, or dens, were constructed on Ubin, one at Noordin Beach and the other near the sensory trail pond.

"The holts are built to the size of the smaller otters," explained NParks Pulau Ubin deputy director Choi Yook Sau.

The habitats of several bird species were also enhanced. ITE College East students installed nest boxes that could be used by the blue-throated bee-eater, as well planted trees where baya weavers can build their nests.

Yesterday also marked the first BioBlitz @ Ubin, a 24-hour survey where members of the public joined 35 naturalists and researchers to document biodiversity on the island.