Fun with Nocturnal Animals at the Rail Corridor

Fun with Nocturnal Animals at the Rail Corridor
By Gloria Seow, Education Committee Vice Chairperson
Photos by Gloria Seow & Lena Chow

The Rail Corridor is teeming with nocturnal wildlife.

With nature walks grinding to a halt during the two-year pandemic, it was a delight to gather once more on 21 April 2022 for a cool night walk at the Rail Corridor to seek out nocturnal animals. We split into two groups of 20 persons each, led by volunteers and professional nature guides Gloria Seow and Andrew Tay respectively. The walk was conducted with Covid-19 safe management measures in place. Both groups started at opposite ends of the Rail Corridor to avoid intermingling, with safe distancing between sub-groups.  

Armed with torches and a huge dose of enthusiasm, Gloria’s group set off from The Rail Mall and walked the grassy stretch towards Bukit Timah Nature Reserve. We shared the path with many night cyclists. Almost immediately, we spotted a Sunda Colugo (Galeopterus variegatus) up a tree. Closely related to primates, the Colugo has a membrane called the patagium that connects its limbs, tail and neck. When fully opened, this mammal looks like a kite and is able to glide up to 136 m between trees. It has even been observed ‘flying’ across a six-lane highway, never mind the cars below.

Next, we explored the freshwater stream that ran parallel to the path. We encountered Lowland Freshwater Crabs (Parathelphusa maculata) scavenging for food and in turn keeping the stream clean. Stirring the muddy bottom was the occasional Common Walking Catfish. During the rainy season, this Catfish can gulp air directly and wriggle between puddles, ‘walking’ from one waterbody to another. Its ‘whiskers’ (barbels) enable prey location even under muddy conditions.

Lowland Freshwater Crab

Ghost Shrimps (Macrobrachium spp) were present at some stretches, sometimes arching their body and shooting backwards when threatened. Participants were excited to see several Malayan Giant Frogs (Limnonectes blythii), marvelling at their enormous getaway leaps. Where the water was more settled, we found the tadpoles of the Copper-cheeked Frog (Chalcorana labialis). The curious bird-like call of the Masked Rough-sided Frog (Pulchrana laterimaculata) and the incessant clicks of the Dark-sided Chorus Frogs (Microhyla heymonsi) proved intriguing. Joining the night chorus were crickets and katydids. We learnt that only male crickets sport wings, where one wing has a comb-like structure while the other has a scraper to produce the classic nocturnal soundscape for mate location in the dark.

 
Malayan Giant Frog

Gloria deployed her ultra-violet (UV) torch and revealed that certain lifeforms like insects, fungi, lichens and plants indeed glow in the dark. For example, chlorophyll in plants absorbs the invisible UV rays and re-emits them as red light. Kids were enthralled that the plastic in their sports shoes provided a multi-coloured UV light show.

The mesmerising effect of glow-in-the-dark UV light

There were many spiders sitting in their orb webs and waiting for aerial insects to blunder in. We learnt that only 50% of spiders spin webs, mostly at night. Gloria pointed out a well-camouflaged Two-tailed Spider (Hersilia sp) waiting on a concrete pillar sans web. When an insect comes within range, this spider will jump on it and bind it in spider silk before envenomating it.

Despite looking hard, the Common Palm Civet (Paradoxurus hermaphroditus) did not make an appearance. Instead, we were treated to flight displays of Common Fruit Bats (Cynopterus brachyotis) zipping overhead and feasting on Rough-leafed Stem Figs and Yellow Stem Figs. We turned around at the rail marker halfway between Woodlands and Tanjong Pagar. Here, participants learnt that conserving the 24-km long Rail Corridor is important as it provides connectivity for wildlife in different forest patches to move and breed freely. All told, it was a fun first outing after the long hiatus.