By
Gloria Seow, Education Committee Vice Chairperson
Photos
by Lena Chow & Gloria Seow
The
year-end monsoon brings out the croaky choir which was why nightfall of 2
December 2017 saw us gathering at Tampines Eco-Green. Here, the combination of
rain and uneven ground creates a multitude of temporary water puddles ideal for
egg-laying and tadpole-raising. With torches ablaze, we set off on our frog hunt.
The grassy verge between the park and the MRT track quickly produced several
Dark-sided Chorus Frogs (Microhyla heymonsi). This 2 to 2.5 cm long frog
has a pair of thin blackish lines that run down the sides of its bronze body
from snout to rear. Many were amazed that despite its smallness, it has a loud
rattling call to attract mates. Another tiny frog of the same size that we
flushed was the Painted Chorus Frog (Microhyla butleri) with its
distinctive 'hour glass' patterning on its back.
Then
we sighted our first Banded Bullfrog (Kaloula pulchra) in the short grass. At 7 to 8 cm long, this
frog stands out with its chubby appearance, narrow mouth, and two thick orangey
bands that stretch down each side of the body. When threatened, it inflates
itself. The Banded Bullfrog feeds on ants, termites, earthworms, flies,
crickets, moths and grasshoppers. It advertises its presence with a soothing
bellow that can be commonly heard after showers. In our two-hour walk, our
first sighting ballooned to some 50 Banded Bull Frogs counted, showing how
successful this introduced species is in Singapore.
Dark-sided Chorus Frog
Our
island has around 10 commensal frogs with humans (ie. adaptable species able to
survive in man-made and disturbed habitats including grassland, roadside
puddles and storm drains). All of Tampines Eco-Green’s frogs are commensals. In
contrast, the majority of Singapore's native frog species can only live in
relatively undisturbed habitats such as primary and/or secondary forests.
Hence, such frogs can be wiped out by habitat loss if forests are cleared for
development.
Painted Chorus Frog
With
so many frogs at Tampines Eco-Green, there were bound to be predators. True
enough, Auntie Gloria spotted our first snake – an attractive
red-black-and-brown Striped Kukri (Oligodon octolineatus) – a 65-cm long
adult that was moving silently on the ground amidst the bushes flanking the
grassy path. The half-exposed non-venomous snake froze for a few seconds when
we trained our beams on it. It then slithered elegantly into the shrubs and
vanished. Next, Auntie Lena found a 7.5-cm long Four-lined Tree Frog (Polypedates
leucomystax), easily identified by four thin lines running down its back
(although certain individuals have speckled, mottled or plain backs). As an
arboreal species, it has expanded flattened tips to its fingers and toes that
help it cling onto trees. This frog constructs a foam nest on vegetation or
rocks above a pool of water, inside which eggs and tadpoles develop in safety.
As they grow larger, the tadpoles fall into the water below or are swept down
by rain.
The iridescent Sunbeam Snake was our third snake for the
trip.
Only
one Asian Toad (Duttaphrynus melanostictus) was seen even though this
species is widespread throughout Singapore. It was covered in warts, as is
typical of toads, and was sitting upright, quite unafraid of us. Females
(11.5-cm) are bigger than males (8.5-cm), as is the case with most other frog
species. Another frog that crossed our path was the 5-cm to 6-cm long Field
Frog (Fejervarya limnocharis). Being skittish, it made a plop sound as
it jumped into a pond to escape from us. If you are using a torch, this frog
can be noticed from a distance as it has strong eye shine. Our second snake for
the walk was a baby Black-spitting Cobra (Naja sumatrana), unfortunately
a dead specimen. We also had sporadic sightings of a rat climbing a tree, fruit
bats flying around, a Changeable Lizard (Calotes versicolor), and a
Malayan Water Monitor (Varanus salvator). Our final snake was a
beautiful Sunbeam Snake (Xenopeltis unicolor) found by Uncle Ivan. The
Sunbeam is so named because its smooth scales are iridescent under strong
sunlight or camera flash.
On
other nights, friends have witnessed a Sunbeam Snake eating a Striped Kukri at
Tampines Eco-Green, and seen other cool snakes such as the Reticulated Python (Python
reticulatus) and the introduced White-spotted Slug Snake (Pareas
margaritophorus). Still, we were mightily pleased that our big group
enjoyed this many sightings.