The following is an excerpt about the terrestrial fauna survey from the EIS report for Bukit Batok Hillside Park area (HDB BB EIS Report Final_rev13), dated 1 June 2020, prepared for Housing and Development Board (HDB) of Singapore.
“Many of the species recorded during these surveys are considered to be widespread and common in secondary vegetation and parkland across Singapore. However, the presence of some forest-dependent species, such as the Malay Tailed Judy (Abisara savitri savitri), Copper-cheeked Frog (Chalcorana labialis), Common Treeshrew (Tupaia glis), and Slender Squirrel (Sundasciurus tenuis) shows that the survey area may serve as a refugium for some of these species.
Due to the ongoing construction work taking place at the edges of the survey area, patches of grassland and small pools have been created. All of the damselfly and dragonfly species are typical of open areas, as are quite a number of butterflies. Among the amphibians, the Field Frog (Fejervarya limnocharis) was only found at the periphery of the construction sites, and was absent at the pond at the forest edge.
The number of Wild Boar (Sus scrofa) present in Bukit Batok Hillside Park area is unknown. The two camera traps that documented the presence of Wild Boar were placed at different areas of the site; one was located along the stream, while the other was near the top of the ridge, in close proximity to an old wallow. Each camera captured a single individual, a lone adult male. Based on the general scarcity of signs of Wild Boar activity during the surveys, and the territorial behaviour of the adult male Wild Boar, it is likely that there is only one resident individual in this forest patch, although the possibility of more individuals wandering from other nearby forest patches cannot be ruled out.
Other species that have been recorded from similar secondary forest habitats such as Bukit Batok Nature Park, may be present within the survey area but were not documented during the surveys. These include the more uncommon animals such as the Sunda Colugo (Galeopterus variegatus), Sunda Pangolin (Manis javanica), Horsfield’s Flying Squirrel (Iomys horsfieldii), and Lowland Freshwater Crab (Parathelphusa maculata). These species are rarely observed outside of Singapore’s central nature reserves and Bukit Batok Nature Park, but are often difficult to detect, with some being nocturnal or arboreal. Therefore, while they were not observed during the surveys, we cannot discount the possibility that some of these species may still be present at Bukit Batok Hillside Park. The non-native East Asian Ornate Chorus Frog (Microhyla fissipes) was not previously recorded in Bukit Batok; this may represent a new locality record for this species in Singapore.
It is also important to note that these surveys took place outside of the migratory season for birds; surveys conducted when various passage migrants and winter visitors may be found in Singapore would likely yield very different results.
Although the survey area is a small, isolated patch of secondary forest with relatively few species of conservation importance, its potential role in maintaining connectivity for birds and other animal species cannot be discounted. With the ongoing development of the Tengah area as a new housing estate, it is likely that some animals may move to the Bukit Batok Hillside Park area, and then disperse to other forest patches in Bukit Batok, possibly reaching Bukit Timah Nature Reserve via Bukit Batok Nature Park.”