Monday, December 31, 2012

Crabby rain at Pasir Ris Park Mangrove

For the last fieldtrip of the year, I decided I shall do away with intertidal shore and reef.  Actually, it was not a planned fieldtrip. After reading about Ria's recent visit to the Pasir Ris Park's mangrove at night, I wanted to visit it. Having done a few guided walk at this place with the Naked Hermit Crabs and visited the place myself a few times, I have not actually seen a mangrove at night.

So I spent the last two days of 2012 at the Pasir Ris Park magrove with my friend. Two days because we started late at night on 30th December and ened on 31st December early morning.
Night Time is great for close observation of animals. They hardly move and you are able to get real close to them.

As we entered the mangrove, I spotted a pipefish and a juvenile dog-faced water snake emerging from its hole in a small stream nearby.
Juvenile dog-faced water snake (Cerberus schneiderii)
The mangrove housed many different types of spiders - big, small, adult, babies... etc.
I am very poor with spider identification, so I try to identify the spider species to my best ability.
Mangrove Big-Jawed Spider (Tetragnatha josephi)?
Lynx spider (Family Oxyopidae)
Singapore Fishing Spider (Thalassius sp.)? with egg sac.
Unknown spider 1
Singapore Fishing Spider (Thalassius sp.) on water surface.
Hatched baby spiders
Unknown spider 2
There are many snails and slugs creeping on tree trucks.
Red chut-chut snail (Cerithidea obtusa)
See how it "glues" itself onto the tree truck.
Red chut-chut snail (Cerithidea obtusa)
Mangrove murex (Chicoreus capuncinus)
Lined nerite snail (Nerita articulata) pooping
Belongkeng snail (Ellobium sp.) pooping
Three-some: Lined nerite, red chut-chut snail and mangrove ear snail (Cassidula sp.)

At a particular spot where we explored, there was a large suspicious pile of calm shells. I suppose that humans have thrown them here?
Pile of clam shells.
As the tide rises in the mangrove, more exciting things happens in the mangrove.
Oh.... what is this thick rubber like thing in the water?

It is a snake eel (Family Ophichthidae)!
In fact we actually saw at least five of them in various sizes during this trip. Wow!
Snake eel hunting for food in a hole.
Scavenging snake eel
The rising tide and night time also allows us to have a closer look at mudskippers. They do stay high up on the tree trucks during high tide (as high as my eye level).
Mudskipper outside its burrow.
Slender mudskipper (Periophthalmus gracilis)?
A suction-like plate to help stay on the tree truck?
Giant mudskipper (Periophthalmodon schlosseri)
Unknown type of mudskipper, quite large.
How can we forget about the crabs in the mangrove?
Pasir Ris Park mangrove is one of the best locations to see large tree-climbing crabs (Family Sesarmidae). When the tides rises, the crabs climb trees to as high as eye level on the boardwalk.
Here are some of the crabs we saw:
Mama crab
Eggs of mama crab
Acrobatic crab
Face-banded crab (green band?)
Face-banded crab (blue band)
I can't remember what crab this is.
It was raining crabs in the mangroves as the tree-climbing crabs will drop into the water from the tree trucks or branches when they sense danger approaching them. We noticed that the crabs do not just simply release their grip and fall straight down. They actually do a backwards fall, probably to avoid hitting the base of the tree. Pretty clever.

The sound of crabs falling into water was quite amusing initially. However it gets rather irritating after a  while as the crabs are falling into water everywhere. It sounds like endless random stones dropping into water, sometimes a few, sometimes many.

We also saw at least two pairs of mating horseshoe crabs but the knee deep water does not allow my camera to take a good photo of it. I found a red ear slider turtle swimming in the water at the back mangrove. It was rather hilarious. The red ear slider is an invasive species to Singapore's ecosystem and they are seen in our ecosystem because of human release.

It was a very animal quiet night in the mangrove. We did not come across any birds or larger snakes nor even hear their presence. What surprised me was that even in the wee hours at night and early morning, there were young adults "playing" on the boardwalk and other visitors taking a walk on the boardwalk.

What a fun and interesting way to end my fieldtrips for the year 2012.
There will be more fieldtrips in 2013!

You can check out what Ria Tan saw during her recent trip there here: Strange snakey thing at Pasir Ris

My work attachment at RMBR

While my colleagues are already enjoying their long deserved holidays, I set aside two weeks of my holidays for a MOE Teacher's Work Attachment programme. I have chosen the Raffles Museum of Biodiversity Research (RMBR) for my work attachment programme.

My work attachment period was 3 - 14 December 2012.
I chose RMBR as it was one of the places which I was interested to find out how specimens, after collected from sites, are processed, preserved, document and kept in a biodiversity museum. Furthermore, the work description posted for this organisation allows me to work with the available specimens to create educational materials.

However the museum's gallery was closing soon in view of the big house moving to the new Lee Kong Chian Natural History Museum, set for completion in 2014. There was not much of a need to create educational materials at the moment.

I spent my two weeks of work attachment in the wet collections section of the museum, helping out Siong Kiat, the wet collections' curator. Wet collections refers to specimens (mostly marine animals) that requires storing in preservation liquids such as ethanol and formalin (formaldehyde). Majority of the specimens I worked with are stored in 75% ethanol.

Here's the blog post from RMBR about my work attachment stint with them.
Image capture of the blog post.
Apart from the days of working in the wet collections research room, I got a chance to help change the dinosaur bones in the public gallery. Here I am with the leg bones of the triceratops, after changing and ready for viewing.
Triceratops' leg bones
The biggest takeaway from this work attachment is understanding better the importance of the type specimen. A simple way to explain type specimen can be found from the Smithsonian National Museum of Natural History:

In taxonomy, the science of identifying, naming, and classifying species, the primary type specimen (or sometimes a series of specimens) serves as the scientific name-bearing representative for any animal or plant species. A secondary type specimen is a specimen of the type series other than a primary type. A primary type is the objective standard of reference for the identification and naming of species.
Type specimens are important to scientists that study the classification of organisms and to all studies of comparative biology.

In any natural history museum, the value of the museum is actually determined by the number of type specimens it has, not the number of valuable exhibits. The number of type specimens tell other scientists how active the museum is in scientific research.

There are a few kinds of type specimen: Syntypes, Lectotype, Paralectotype, Holotype, Paratype, Hapantotype, Neotype and Allotype. More information about each kind of the type specimen can be found on the International Commission on Zoological Nomenclature.

Is it boring doing very similar things each day at the museum?
Nope, I was able to look and examine in closer details the specimens collected from various sites, which most of them I have been to.

Was it enjoyable doing working at the museum?
Sure it was, I had a lot of fun in the museum.

Would you like to do it again if there was such opportunity?
Yes. And if I have the time, I won't mind volunteering.

Saturday, December 8, 2012

NParks annual volunteer appreciation day

Today is a special day as the National Parks Board (NParks) is having her annual Volunteers Appreciation Day this morning at Hort Park. This event was also organised in celebration of International Volunteer Day, which fell on 5 December.

Some of the volunteers from the Naked Hermit Crabs spent this special day sharing the beauty of Chek Jawa to our visitors while some others attended the appreciation event. Read about the happenings at Chek Jawa here.

I was unable to attend the event today as I was guiding at Chek Jawa.
However there are news reports from the media and National Development Minister Khaw Boon Wan posted an entry in his work blog.

I am one of the 3 volunteers to featured in Minister's blog post and I quote a portion of his entry.
"Ms Heng Pei Yan – a teacher– participated in the Comprehensive Marine Biodiversity Survey early this year.  Despite the risk of getting stung by marine organisms and having to trudge through knee-deep mud, she was undeterred and gamely participated in the survey simply because of her passion for nature."

The following are the links of the coverages of the event that I have found:

Media reports:
Channel NewsAsia [8 Dec 2012] - NParks sees healthy increase in volunteer numbers
AsiaOne News (SPH) - NParks volunteers honoured at inaugural event
Straits Times [8 Dec 2012] - More people volunteering at National Parks
The Sunday Times, pg 21 [9 Dec 2012] - Hats off to park volunteers

Blog posts:
National Development Minister Khaw Boon Wan - Giving back to nature
WildSingapore News

Social media:
NParks (Facebook) -

You can find out about how you can be a volunteer with NParks through their volunteer webpage.

Wild boars, hornbill and an unusual gathering of fiddler crabs at Chek Jawa

The Naked Hermit Crabs held our last guided walk at Chek Jawa for year 2012 today!

There were a number of interesting sightings at Chek Jawa today.
Upon arrival at the entrance of Chek Jawa, 3 wild boars came out of their foraging activities to meet us.
One of them approached us real close and started sniffing around without any fear. 
Wild boar sniffing at me
This can be disturbing as it could lead to unwanted accidents to members of the public if they were to start screaming and acting aggressive towards the wild boar.
We (the guides) also had an opportunity to witness the wild boar grooming her child.
Grooming the child
Here's s video to the grooming.

Soon after the call of the oriental pied-hornbill (Anthracoceros albirostris) diverted our attention away from the wild boar towards the calling sound. 
Turns out that there was a hornbill perched at one the highly visible man-made nesting box. It seems to be calling out to a female, trying to invite her to this nesting box. 
Male hornbill perched at the nesting box
I hope that this nesting box will be sealed when the next guided walk happens.

Despite only having 4 guiding groups today, everyone were all ready to bring our 70 over visitors around Chek Jawa.
Our visitors for the December guided walk
I guided a group of 16 family members, consisting of 3 generations from a grandmother, her children, in-laws and grandchildren.
Grandchildren looking at the animals in the mangrove
With an elderly in my group, I skipped the Jejawi tower. Being a nature guide, we have to work with the condition presented to us on the spot and make adjustments.

We saw a lot of crabs today. In the mangrove, we saw a few big tree-climbing crabs (Episesarma sp.). It has been a very long time since I last saw a decent size tree-climbing crab. Usually, I see smaller sized ones.
Tree-climbing crab dragging a leave back
Tree-climbing crab foraging
Another tree-climbing crab
Towards the end of the mangrove section, one of my young visitor was commented on the numerous spider webs everywhere. Coincidentally, we saw a mangrove St. Andrew's cross spider (Argiope mangal). It had two sets of zig zag lines on the lower part of the web.
Mangrove St. Andrew's cross spider
On the seagrass lagoon, the visitors and the guides observed an unusual behaviour of the fiddler crabs.
They seemed to gathering themselves in very close manner, some in groups and some in lines.
Fiddler crab groups 1
Fiddler crabs group 2

Those in lines had even stranger behaviour. The male fiddler crabs were on the left while the female fiddler crabs were on the right of the line.
Fiddler crabs in a line
Here is a video of the fiddler crabs in their unusual gathering.

I had some free time after the guided walk as my group had already called the van for the trip back to the village centre. I took a short walk down to take a look at the shortcut path.
There was a dead praying mantis hanging from a tree.
Front view of the praying mantis
Side view
Tucked in a folded leave, a spider is hiding in there. I am not sure of its identity.
Spider in the folded leave
Closeup view of the spider
Further down on the path, the flowers of the sea poison tree (Barringtonia asiatica) have bloomed.
Flower of sea poison
Near the jejawi tower, I found another spider. I think it is the big-bellied tylorida (Tylorida ventralis).
Big-bellied tylorida
Nearby the spider, there was a pair of tiny beetles.
And just after the start of the guided walk route, I found a snail shell.
Snail shell
Back at House No. 1, the children are already busy working on their entry for our guest book.
Everyone working hard at their entries 
 Making use of images taken during the walk
Various sitting positions
Daddy helps with the drawings
Sankar had a request from his visitors to have a picture taken him. The children each gave him a hug before that. Aww.....

We were blessed with good cloudy weather this morning. Worrying that the thunderstorm forecast in the late morning will affect the guided walk, the guides made some effort to finish the walk slightly earlier than usual.

Lunch was as usual, at the sisters' restaurant with our standard dishes. Since there were fewer of the guides around today, we ordered less food. However the 2 black pepper crabs were too huge for us to finish everything. Ivan decided to takeaway the leftovers.

Thank you to LK, PY, Sankar and RT (Kok Sheng's student) for helping with the guiding today.
The rest of the regular guides were at the NParks' Volunteer Appreciation Day.
Read about it here.


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