Sunday, February 24, 2008

Checking out Central Catchment Nature Reserve

Was thinking one of these days may have to change my blog title to include terrestrial stuff as well. Been doing so many terrestrial walks these days! :)

But will I be able to find another name which I like as much? Hmm... Anyway, went with ST, LK and a few other nature lovers to Central Catchment Nature Reserve on Sunday, and here are some of the little animals we saw.

We found this very pretty skink (Family Scincidae) near a drain. Have no idea what species it is though. Skinks are the most diverse group of lizards, with about 1,200 species in the family!

ST found this cicada (Family Cicadidae). Male cicadas have loud noisemakers on the sides of the abdominal base. They are the ones making the loud repeating noise you hear in the forest in the day.

Spotted at least two of these Coeliccia octogesima. Unlike most of the other species of damselflies that I've seen, this one held its wings apart instead of holding them together vertically. Not sure why.

Have no idea what dragonfly this is. Had a hard time getting a good shot as it kept flying around and stayed in the shade, meaning I had to use flash and thus the colour didn't come out well.

Have no idea what dragonfly this is as well. Will try to confirm the IDs and update the above 2 as soon as possible :P

Prof T was quite happy to see this jumping spider (Bathippus digitalis) I found. Seems like he hasn't seen it before. This was a rather cooperative one compared to most other jumpers I've encountered. It just stayed still most of the time and let just took as many photos as we wanted. Jumping spiders are able to jump from place to place secured by a silk tether. They also have good vision for hunting and navigating.

There were lots of little red beetles (Order Coleoptera) on the leaves too.

Found lots of harvestman (Order Opiliones), which are also known as daddy long legs. Being close relatives of the spiders (from the same family Arachnida), they also have eight legs. But unlike spiders, their two main body sections are nearly joined, and they also have no venom or silk glands.

Everyone was really excited when we found this tarantula (Family Theraphosidae)! Actually, to be precise, it found us... it climbed up LK's leg! And Prof T actually commented how come he never had such luck before. Haha. Anyway, the name tarantula comes from the town of Taranto in Southern Italy, and was originally used for an unrelated species of European spider.

After a few rounds of photo-taking, the tarantula was obviously getting impatient, and took on a defensive mode. However, this only managed to encourage more photo-taking. Anyway, this is probably a Singapore tarantula (Phlogiellus inermis).

We also found this strange caterpillar with a huge head.

And more dragonflies! This is probably a Tyriobapta torrida.

And this is a female Tyriobapta torrida.

Near a pond, we also found this pretty little green frog, probably a copper-cheeked frog (Rana chalconota).

We also found this strange caterpillar. No idea what caterpillar it is as well.

Soon, it was getting dark and we had to go.

Thanks LK for inviting us to go to this interesting trip!

Saturday, February 23, 2008

A Walk with the Trainees at Semakau

While the other Semakau guides were on guiding duty today, I was there for another reason - to run a practical session for the new guides!

And here're some of the things we saw today.

When LK was telling the trainees more about the great billed heron (Ardea sumatrana), I suddenly spotted one in one of the landfill cells and shouted to the rest. Unfortunately, my camera zoom wasn't fantastic, and so I only managed to get a blurry shot. This is supposed to be the tallest bird in Singapore, and usually they can only be found on our offshore islands or the western coast, usually a pair on each of location. However, on a few occasions I've seen 4 of them on Semakau - a pair on each far end of the intertidal flats!

The sand-sifting sea star (Archaster typicus) used to be very common even on our mainland shores, but these days, they are mostly found on the offshore islands too, as many of our natural sandy shores had been reclaimed.

Found this juvenile mangrove horseshoe crab (Carcinoscorpius rotundicauda) creeping just underneath the sand. This armoured critter is not a true crab though, and is more closely related to spiders and scorpions. Often called living fossils, these animals were already around even before the dinosaurs roamed the Earth!

The hunter-seekers found this dead stingray, which I had some problem identifying because the edges were already badly chewed off by other animals and the colour was already quite off. My guess is that it could be a blue-spotted stingray (Dasyatis kuhlii), as I could vaguely see lots of off-coloured spots on its back, but can't really say for sure. Will really appreciate it if anyone can help to ID it. (Update: ST says in his blog that it is probably a coachwhip ray, Himantura uarnak. This ray is also called the black-spotted whipray. Certainly looks more like it rather than the blue-spotted stingray after comparing the photos.)

Not to be confused with the blue-spotted fantail ray (Taeniura lymma) which is more rounded in shape, the blue-spotted stingray can grow to a disc width of at least 40cm sometimes (about the size of the one we saw today). The last time I saw a living one was on Beting Bronok, but that was much smaller with its disc width around 15cm.

After crossing the seagrass meadow, I found this dragonfish sea cucumber (Stichopus horrens). Sea cucumbers of this genus do not eject the sticky threads for defense, but they may eject their internal organs. When remove from the water for too long, they can actually "melt", become very limp and eventually disintegrate all together. However, if they are not too badly "melted", they are able to reverse this process and recover.

For at least the past half a year, I've been finding noble volutes (Cymbiola nobilis) laying eggs on both our northern and southern islands.

We also managed to find the resident gigantic carpet anemone (Stichodactyla gigantea). Couldn't find the resident ocellaris clownfish though...

And yet another great find by our hunter-seekers - a heart cockle (Corculum cardissa)! Such a brilliantly coloured one some more!

What's more fascinating was - the other side was in a totally different colour! Bright blue! Unlike most other clams which have their valves flatten like plates, this clam has its opening of the valves cutting across the centre of the 'heart'! Can you see the line running down the middle?

Our hunter-seekers managed to find us 2 ocellated sea cucumber (Stichopus ocellatus) today. Closely related to the dragonfish sea cucumber, it can suffer from the "melting effect" too.

Our very-hardworking hunter-seekers also found us several types of nudibranchs! They found 4 orange-spotted gymnodoris nudibranchs (Gymnodoris rubropapulosa) together on some seaweed. Nudibranch means "naked gills", as many of them have their gills exposed. You will be able to see the flowery gills on the back of the above nudibranchs.

Two other species of nudibranchs found were the polka dot nudibranch (Jorunna funebris) and the green ceratosoma nudibranch (Ceratosoma sinuata).

We sure have lots of luck with sea cucumbers today, as we also saw 2 stonefish sea cucumbers (Actinopyga lecanora) which are usually found among rocks and corals in the coral reef...

And a sandfish sea cucumber (Holothuria scabra), which can burrow into the sand. This sea cucumber is a very popular commercial species, especially during the Chinese New Year period. It is edible, but must be properly processed to remove the toxins.

And here's me with a knobbly sea star (Protoreaster nodosus). To think that I've seen them so many times, but had never taken a photo with them! Finally did it today. The knobbly sea star is one of the biggest sea stars in Singapore waters, and can grow up to 30cm wide.

All in all, it is yet another enjoyable trip! Hopefully it had been a good experience for the trainees too :P

See also:
1. Semakau Inter-tidal Walk on 23 February 2008 by ST
2. Semakau Inter-Tidal Walk on 23 Feb 2008 by JL
3. Training at Semakau intertidal by KS

Sunday, February 17, 2008

Wet Wet Tuas

Today, I finally got the opportunity to visit the grassland at Tuas!

Although this is actually a piece of reclaimed land, it managed to establish itself as one of the best spots for checking out dragonflies in Singapore! Unfortunately, the entire area will be converted into a new motor racing ground soon. In fact, the bulldozers were probably just a few hundred metres from where we were just now. Will expect the area that we explored today to be gone perhaps within a month or two...

Anyway, with me today were LK, ST, SY, JL and HW.

Even before we entered the grassland, we saw this tawny coster butterfly (Acraea violae) which looked like it has just emerged from its chrysalis. It was still quite weak, and couldn't even stretch out its wings to fly.

Indeed, not too far away on a leaf blade just below the butterfly, we found the above broken chrysalis.

As we were heading towards the area with the most dragonflies, we saw lots of pretty wild orchids among the tall grasses. According to SY, its probably a ground orchid, Spathoglottis plicata.

The morning glorys were in their full glory too!

And hiding among the resam ferns were lots of slender pitcher plants (Nepenthes gracilis)! I noticed that those nearer to the ground were red in colour...

...while those higher up were greener. Not quite sure why though.

Several of the pitcher plants obviously just bloomed not too long ago, as we saw lots of dried flowers.

Some of them had bunches of fruits too.

And in some of the pitchers, we found crab spiders hiding in them. They presumably attack insects attracted by the sugary liquid secreted by the pitchers. The above is a female spider.

On some pitchers, we found the male crab spiders too.

Here's another species of pitcher plant which doesn't grew into a vine like the previous one. Not sure of the species though.

Like I mentioned earlier, Tuas grassland is a great place for spotting dragonflies. The above is a female Diplacodes trivialis. The male ones are blue in colour. Didn't managed to get a photo of the male ones, as they simply refused to stop at a spot long enough for a good shot.

By the way, you may notice that dragonflies have relatively large eyes. These eyes supposedly may each contain as many as 30,000 individual lenses!

This Nannophya pygmaea was supposed to be the smallest species of dragonfly in Singapore. The male ones are red in colour.

Here's another male, but somehow it's not as red as the previous one. Could it be immature yet? Not quite sure though.

And here's a female, which has a duller colour. Many female animals have duller colours so as to camouflage better from predators when they are breeding.

We also saw a Ictinogomphus decoratus, which is commonly found around drains, ponds and lake margins.

There were indeed many different species of dragonflies at the grassland, but unfortunately most of them were rather alert and refused to stay long enough at a spot for us to take good shots.

Apart from dragonflies, there were many damselflies too. Damselflies are closely related to the dragonflies. They are both insects from the order Odonata.

This damselfly is probably a male Ischnura senegalensis. It is quite a common damselfly in Singapore. From this photo, you can also see that the area is flooded, and that's why it's so popular with dragonflies and damselflies, as they lay their eggs in water and their nymphs spent their childhood underwater!

This one is probably a Ceriagrion cerinorubellum. Unlike dragonflies, damselflies hold their wings close together vertically when they are resting. The former usually hold their wings by their sides perpendicularly.

This unfortunate one got caught in a spider web. Not to deprive the spider of a good meal, we did not rescue it.

A red damselfly was even more unfortunate, and was caught by another orange damselfly, probably a female Ischnura senegalensis. This species supposedly has several colour variations for the females. As I watched, the red damselfly was still wriggling away as the orange one munched on its head.

All in all, today had been a great day. Unfortunately this place will be developed soon. Hopefully I can find time to revisit it before it's totally gone...

Thanks to LK for inviting us to this trip, and the rest for your great company!

See also:
1. Tuas Marshlands by SY
2. Discovery at Tuas Grasslands on 17 Feb 2008 by JL
3. Carnivorous Plants (Tuas) by ST