Tuesday, February 23, 2010

21 Feb 2010: They are back at Sungei Buloh!

Instead of the usual bright and sunny morning, the skies were gloomy as I approached the Kranji area. I was a little disappointed thinking that I won't get to see much since bird activities tend to be reduced when theres lesser sunshine. Worst of all, I was afraid that it will rain! Thankfully the weather held up and this wonderful nature reserve never fails to surprise me.

Happy that the tide was very low when I reached the reserve as this means that there is a chance to see the Esturine Crocodile (Crocodylus porosus). "Really got crocodile meh? Will it appear?" I overheard the skeptical conversation of group of visitors. "Yah, there is. I'm sure it is around here (erh) somewhere. I've seen it before' the kaypo me interrupted them, with a smile of course. Indeed, (many) minutes later,  Crocodile 2 (I think) appeared!

It harboured around the usual area near the main bridge and was submerged most of the time, except for its eyes.

Then, it swam into to a small pool of water by the river bank. This is the third time I've seen it there. At this spot, the crocodile is very well camouflaged like a log and difficult to spot unless with a pair of keen eyes, perhaps the reason for its stopover.

I was hoping really hard for it to move ashore but instead, the crocodile decided to swim away fairly swiftly a while later. It does so by tucking its feet to its sides while swimming which allows it to swim faster as water resistance is decreased.

It headed towards the opposite bank and soon, I lost sight of it after it dipped below the surface. For ten minutes, it didnt resurface, and I presumed that it had swam away.

I decided to try my luck at birding at platform 2 and met a huge Malayan Water Monitor (Veranus salvator) along the trail, enjoying a bask.

As I walked on, a family of 4 walked past me, heading towards the monitor liazard. Few seconds later, I heard a commotion. I turned and was shocked that the grandfather was standing just next to the monitor lizard, which flinged its tail at the grandfather's leg in defence. Perhaps a reflexed reaction, the grandfather, to my horror, raised his feet to kick the lizard! (although I cant tell whether he touched the lizard from where I was standing).

I quickly ran over to check if he was hurt and attempted to explain why they shouldnt do so, but was ignored, and even shot a dirty look. ARGH!! Really, this reptile may look menacing, but they are shy of human beings. They typically flee instead of fight when approached. It was just basking in the sun, so we really should be leaving them alone.

I hang around platform 2 for some time (still feeling sore about the monitor lizard episode), and made my way back to the main bridge. I was mad happy to see the crocodile on the opposite bank. Finally, a full view of it on land!

It slowly opened its mouth, probably to regulate its temperature/ cool off, due to a lack of sweat glands.

Side view of the crocodile with its mouth opened.

The dentist says....'ah'...



For some reasons, the crocodile made a noise that sounded like a cough/ hiss and snapped its jaws closed. I found clips of crocodile calls by Dr. Adam Britton on the internet and what I heard sounds like a threat call (listen to the first & second clip - although recorded from a different species), not sure though.

I didnt realised how big this crocodile is as it is often submerged in water. From snout to tail, it is approximately 3m in length. With plenty of food such as fishes in the reserve, I won't be surprised if it grows larger (and hopefully by then, this top predator won't be removed and the ecosystem upsetted).

Frontal view....


This pack of dogs was pacing up and down the coast from one end to the other. As they walked nearer to where the freshwater pond was, one of them suddenly picked up pace and barked. Soon, a loud squeal was heard. The stray dog was chasing a smooth otter (Lutrogale perspicillata) !!

Thankfully the otter ran into the water in time, and the dog gave up its chase. *Phew*. Clearly, the water is the otter's safer haven given its strength in swimming.

For me, it was always hearsay that the stray dogs attack the otters. I guess I wasnt quite pleased to witness the action myself. Listed as a vulnerable species, I really hope for the Smooth Otter population to remain the same if not grow in size at Sungei Buloh. There are mix views about whether the authorities (and as usual, which one) should cull the dogs. I guess we do not have to put them to sleep, but removing them from the reserve could be an option?

Sunday, February 14, 2010

鳄鱼和水獭, 你们去哪里避年了?

One of the best things to do on a Saturday morning is to go on a nice leisure nature trip, so it was early rise and shine for me on the past 2 saturdays, including 除夕 on which I had a date with Hazel (actually, its more accurate to say that I dragged her along) at Sungei Buloh.

I arrived at the reserve earlier than expected, and was happy to hear the loud flapping of the Pink-necked Green Pigeon's wings (Treron olax vernans) as it landed on a tree near the entrance of the reserve.

A barren tree on one side of the Bamboo River was decorated with a flock of Little Egrets (Egretta garzetta) , and an outstanding Grey Heron (Ardea cinerea) (an Egret-wannabe, you think?).

As usual, with the hope of seeing the otters, I was excited to see sudden ripples in the water towards the main bridge. I was estatic, thinking that it was them! But it was just my imagination as the ripples were caused by a school of fishes, much to Hazel's amusement.

My favorite Stork-billed Kingfisher (Halcyon capensis) helped to decrease my disappointment index with its splendid performance.

Our largest kingfisher in Singapore dived quickly into the water and with great accuracy, it grabbed a fish with its powerful dagger-like beak, before returning to the same branch. As it began devouring its breakfast, the kingfisher showed us its ferociousness as it beats its prey repeatedly on the branch. The Hazel beside me exclaimed 'Wah, so fierce...' with every smack. This hunter eventually swallowed the fish whole.

Unfortunately, tide was really high that morning, and we didnt have any chances in spotting the migratory waders on the mudflats. We decided to focus on our mission to see some reptiles and embarked on Route 1.

The usual voice of the mangroves was exceptionally loud, and we were quick to find the Mangrove Cicada (Purana tigrina) clinging onto the bark of a tree just by the trail. These attention seeking male Cicadas goes all out to attract the opposite gender (just like man, isn't it? =P) by singing using 2 membranes within their abdomen that vibrates.

We froze in our tracks in order not to scare away this bird that was foraging some 10, 20 m infront of us. I didnt manage to take a clear shot, but it looks like the Emerald Dove (Chalcophaps indica). It eventually disappeared into the undergrowth.

I was just sharing the 'gross' encounter with a troop of Cotton Stainer Bugs (Dysdercus decussatus) during a training trip with the RMBR guides some months ago. My dear friend also experienced the same, as I happened to spot another colony of them (estimate the number by multiplying the picture below by 10) congregating on the Sea Hibiscus. Safety in numbers, they say.

Somehow, we were stopped in our tracks by animals several times yesterday. This time round, the Malayan Water Monitor (Veranus salvator) swaggered in front of us. While it is generally not harmful to humans, we were still hesistant in approaching it and were wishing that it would quickly walk into the nearby undergrowth.

The scavenger, instead (as if reading our minds), walked to the middle of the trail and slump itself flat to bask in the sun!! While we know they are cold-blooded and requires the sun's help to warm itself, we can't help being amusd by what seems like its deliberate attempt to frustrate us.

The Batik Golden Web Spider (Nephila antipodiana), recognised by the yellow spots of its upper abdomen, was a common sight. We spotted at least 5-6 of them throughout the walk.

The golden-coloured silk, which gives the spider its name, forms a strong web. The web is built at a slight angle, enabling the catch of larger flying insects.

Can you spot the much smaller spider on the same web? I wonder if its the male spider, which is far smaller in size than the female.

After 3 hours, there were still no crocodile nor otter in sight. We decided to go for a quick walk on the mangrove boardwalk, hoping that the otters will be at the fresh water pond (which, of course, did not happen) after our detour.

As it was high tide, it was no surprise that the tree-climbing crabs (Episesarma sp.) were seen climbing tree trunks above the water level, to avoid aquatic predators. These tree-climbing crabs are also known as Vinegar Crabs. Preserved in vinegar and salt, they were/ are favoured by the Teochew community - must ask my Teochew friends next time.

These 3 individuals lined up orderly in their climb.. 排排坐, 吃果果...

A close up of the Violet Vinegar Crab (Episeserma versicolor), the most common species locally, which has a distinct violet-coloured pincer with white tips.

We also saw several Shield bugs (Calliphara nobilis) on a leaf.

It was almost noon and we decided to call it a day and headed towards the cafeteria. Even before CNY commences, we already started gorging ourselves silly on unhealthy food to satisfy our hunger after a long walk...

While I didnt get to see the crocodiles yesterday, I saw not 1, but 2 Estuarine Crocodiles (Crocodylus porosus) last Saturday.

While processing my photos, I wasnt able to differentiate the 2 individuals effectively, except that the colour looks a wee bit different, the slit behind their eyes a wee different.. and their 'sey' a wee bit different too.

These top predators have been making frequent visits to the reserve. Our ecosystem must be quite healthy, with plenty of fishes for them to feed on. Thus, they are unlikely to pose a danger to us, unless provoked.

Crocodile 1

Crocodile 2

Last Saturday's trip started with a trek at Sungei Kadut. The wet socks and shoes were thankfully worthwhile as we managed to see the flowering Kalak Kambing (Finlaysonia obovata). Read more about this rare mangrove climber at Ron's blog.

I didn't notice that there were 2 pairs of fruits till I took a closer look at the photo at home. These mature fruits were spotted along Kranji Nature trail. The climber's nectar must be quite sweet to have attracted many Weaver Ants (Oecophylla smaragdina)!

We initially thought it was 1 lonely Altas Moth (Attacus atlas) that we saw, but was pleasantly surprised to find a pair whom appeared to be mating. Considered as one of the largest moths in the world, they are apparently cultivated for their brown, wool-like silk, which is said to have greater durability.

My last sighting of the day was the Common Greenback Frog (Hylarana erythraea) , mediating at the fresh water pond. While this frog is fairly shy (and very well camouflaged), it is agile and a very strong jumper

Had a great time on both trips, and you bet, I'll be back very soon to try my luck at sighting the Otters (again) !

And oh yes, Happy Chinese New Year to all! and... Happy Valentines' day too:

Monday, February 1, 2010

Guided walk at Semakau on a (not so) Sunny Sunday afternoon

On my first guided walk in 2010, we were threatened by an overcast weather. Thankfully, we were only douse with a slight drizzle at the end of the walk.

Together with a fellow GV, we were attached to a group of Sec 3 students from Punggol Sec School. Hopefully, the 'Nudibranchs' who felt that they were forced to come for the trip initially would now feel glad that their teachers had forced them to come. =P

Our first few animals of the day were small crabs scampering on the sandy shore, including this cute Soldier Crab (Dotilla myctiroides). Instead of flattened bodies, their bodies are round and they can walk forward unlike other crabs. Soldier Crabs typically move in large troops, probably how its name is derived, but unfortunately this scene is not so common anymore. It feeds on detritus in the sand by scooping sand to its mouth using its pincers. The shifted sand is then discarded in the form of a small round ball.

With some careful observation, we were able to see orange dots darting into burrows. As usual, the male Porcelain Fiddler Crab (Uca annulipes) were eager to attract attention by waving their single huge pincer, as if playing the fiddle. During their mating season, their pincers are clad in even brighter colours to create an alluring appearance (a similar behaviour observed of man too). Apart from being a great asset in courtship, the pincer is actually quite a handicap as it requires more to maintain. Having said so, it is quite a feat to be able to survive with this 'liability', thus females are likely to be attracted to those with larger claws.

Much larger in size as compared the Soldier Crab & Fiddler Crab, the Swimming Crab (Thalamita pelsarti) lifted up its pincers aggressively as we crowded around the container. Swimming crabs are easily identified by their last pair of legs that are paddle-liked (vs the rest of its legs that are pointed) which enables it to swim very well. Their speed and agility, coupled with their long and strong pincer, helps it to catch fish and other fast moving prey.


Our first Sea Cucumber of the day is the Synaptid Sea Cucumber (Family Synaptidae), whom some thought was a worm! This is the longest Sea Cucumber that can grow up to 3m long! This cute small fellow is probably a juvenile, and was gingerly lashing it's feathery feeding tentacles  in the water to feed on small particles. Their body wall is very thin and is thus very delicate, so its important that we do not handle them. Instead of tube feet, they have hooked spicules to stick to things. I wonder if this is the inspiration in the invention of the velcro.

Everyone had a chance to experience the cooling water of one of the longest stretch of Tape Seagrass in Singapore. The Seagrass habitat is important to the entire ecosystem as it provides shelter for many young marine animals. This is in addition to its dutiful role of giving oxygen to our environment when it photosynthsizes. 

The Sandfish Sea Cucumber (Holothuria scabra) surely must make an appearance, especially when CNY is around the corner - this is the species that some human beings deem as a delicacy. However, they must be processed before it is edible as it is mildly poisonous. It is a good burrower in sand, probably thats how it got its name. Unlike us, sea cucumbers circulates water through its body to transfer nutrients and thus can get very stressed out when they are out of water. As such, we should always leave these animals in their natural habitat.

Everyone was familiar with the movie 'Finding Nemo' and was quick to identify the Anemone, which has sticky tentacles with stingers that inject a toxin affecting smaller animals. While these stings do not hurt us very much (except that of the Hell's Fire Anomone), they can leave welts on sensitive skin, which is why we always caution participants in touching any animals.

We didnt see a clownfish but instead an Anemone Shrimp (Periclimenes brevicarpalis) which coats itself with mucus produced by the anemone to prevent being stung. This 'free loader' not only feeds on left over food from the anemone, and also gets protection from predators, however does not return any favour to the anemone.

We were really lucky to see the Moon Snail (Polinices mammilla) as it is usually more active at night. Round and pearly white, just like the moon, it is a ferocious predator of other bivalves and snails. It suffocates its prey by wrapping its huge body around its subject. If this fails, it can secrete an acid to soften the victim's shell, creating a hole with some help from its radula to feed on the prey.

The hunter-seekers also found us a Sand collar which is the Moon Snail's egg mass. The Moon Snail lies at the centre of the collar, turns round and round like a ballet dancer while combining its eggs, mucus and sand in a thick sheet which hardens to form the collar. The Sand Collar disintegrates after the eggs hatch, so we must not touch an intact Sand Collar in case we destroy the thousands of living eggs it contains.

Flatworms like this Acanthozoon sp.are unsegment worms, and are named so because its really very flat! Because it is very flat, it can move into any crevices to hide but are also very fragile and tears easily, so we should never handle them. It doesnt have a respiratory or blood circulation system, instead, oxygen diffuses across its body. While it may look like an elegant swimmer, this carnivore is a predatory as it can inject digestive juices resulting in a liquidfied victim which it will drink up.

Glad to see the mascot of our group - Polka Dot Nudibranch (Jorunna funebris). Nudibranch translated in latin means 'Naked Gills' and refers to the exposed feather-like rhinophores on its back, said to have sensory functions in detecting prey/ mate. A type of sea slug, Nudibranchs are born with shells but loses them as they become adults. Thus, species like the Polka Dot Nudibranch acquire poisons from the blue sponge it feeds on as a defense mechanisim; others develop bad tasting glands to repel predators. Most of the nudibranches are clad in bright colours to warn predators of its poisonous or bad tasting nature.

Here is another species of Nudibranch, the Gymnodoris rubropapulosa,

and the Phyllid Nudibranch (Phyllidiella nigra) which is said to be very poisonous. While we show our emotions when stressed, this Nudibranch can release toxins into the water when they are stressed, which could possibly kill other marine organisms.

Taking the lead in Semakau's gallery of seastars is the Sandsifting Sea Star, which got its name from its behaviour of burrowing in the sand.  This pair that we saw was getting ready for copulation by practising external fertilisation. Although close to each other with alternating arms, their reproductive organs do not meet. They can stay in this position for a while to wait for the best opportunity to release sperms and eggs outside of their body when the tide comes in.

I was really happy to see the 2 juevenile Cushion Star (Culcita novaeguineae). I was sharing with the group that the yellow Cushion Star was slimmer the last few times I saw it, am happy that it is putting on weight and on its way to adulthood! Its round shape and thick calcified body walls makes it more difficult for fish and other predators to bite it.

Wowing the group with its size is our Project Semakau icon, the Knobbly Sea Star (Protoreaster nodosus). Named after the knobs on its body, this Sea Star can grow as wide as 30cm. While they may look quite dangerous with its knobs and bright colours, they are not poisonous. Similar to the Cushion star, its heavy body that is calcified makes it difficult to be preyed on. Interestly, their stiff-looking arms are quite flexible just like a gymnast! Due to the aquarium trade and loss of habitat, these pretty Sea Stars are unfortunately endangered on our shores.

Another good indication of the good health of our shores, this Noble Volute (Cymbiola nobilis) was laying eggs and we were careful not to disturb it in case we cause any destruction.

Not quite evident in the blur picture that I took, I shall play cheat by using a previous photo taken at Semakau. Although often covered with algae, the Noble Volute actually have a very beautiful shell which has also resulted in overcollection and thus the vulnerability of the species. Another fierce predator, the Noble Volute presses its foot on the prey. When the suffocating victim tries to open its shell to breathe, the Volute then capitalises on the chance to attack & feed. 

The Upside-down Jellyfish (Cassiopea sp) has a reason for its posture. Algae lives on the underside of the Jellyfish amongst its tentacles. In order for the algae to photosynthesize, the jellyfish remains in the upside-down position for the algae to get sunlight. While the jellyfish provides shelter and home, the algae shares the food it makes with its host. A win-win situation!

The resident Oscellated Sea Cucumber (Stichopus ocellatus) awed many of us with its sheer size. By far, this is the largest I've seen at Semakau. The eye rings on the body are said to have sensory function to help it move around.

Our 4th Sea Cucumber of the day was the Stonefish Sea Cucumber (Actinopyga lecanora). Unlike the Sandfish Sea Cucumber which has rough skin, the Stonefish Sea Cucumber is much better at beauty care with its smooth surface, looking just like a very well-polished stone.

The tide was low enough for us to meet the smiley resident Fluted Giant Clam (Tridacna squamosa). As the name suggests, this is one of the largest bivalves. Unlike other clams, the Giant Clam's fleshy body plays host to the algae. This is also why the mantle is usually exposed to sunlight to allow the algae maximum resources to make food. This is another animal kingdom example of mutualism as the clam provides a home for the algae, while the algae in return, shares the homemade food.

Presenting the Nudibranchs who were such wonderful participants. Certainly hope that they enjoyed the walk as much as I do. =)