15 March 2012

Checking up Chek Jawa with Dr Dan

Dr Dan is back for his annual trip to check up on Chek Jawa!
We saw dugong feeding trails, Papa hornbill feeding Mama hornbill in her sealed up nest, and lots lots more!

Every year, Dr Dan leads a group of students from the Duke University's Nicholas School of the Environment  on an Urban Tropical Ecology in Singapore trip. During the trip, the students visit various parts of Singapore, from nature areas to the Semakau Landfill and NeWater plants, from attending Parliament to going for talks, as well as experiencing as much of Singapore daily life as they can. As usual, the 2012 team also blog about their trip!
Dr Dan has been a strong advocate of Chek Jawa and is involved in among (many) others, projects such as Kok Sheng's study of Chek Jawa after the mass deaths in 2007. Thus every year, Dr Dan visits Chek Jawa with Kok Sheng to check up on the situation there. Here's Dr Dan's trips in 2010 and 2011.

Here is Kok Sheng showing the students one of the few Common sea stars (Archaster typicus) that are found here today. Before the 2007 event, there were hundreds of these sea stars. Robert later finds several Plain sand stars (Astropecten sp.) which remain abundant.
We are very fortunate to have Robert Heigermoser with us today. Here he is showing us the freshly fallen blooms of the Putat laut tree (Barringtonia asiatica) which has a nice smell. Along the shore, we see lots of fiddler crabs (Uca sp.)!
At the rocks, Dr Dan shares more about the weird lifeforms that can be found here. These include barnacles and Drills (Family Muricidae), the snails that can pierce a hole through the barnacle shell to eat it. I learnt today from Dr Dan that a Drill can't reproduce unless it eats a barnacle!
Oh we have found the empty shell of a Tun snail (Family Tonnidae)! So far we have only seen a live one of these at Changi East, which is mainly a sandy shore.
Kok Sheng found a large shell of a Bonnet snail (Phalium glaucum) that is occupied by a hermit crab. We also see lots of Bonnet snails at Changi East, which we call 'The Lost Coast'. Does it mean Chek Jawa is becoming sandier? What does this mean for the seagrasses, mangroves and other marine life at Chek Jawa? So much more to learn.
Dr Dan tells us more about the Haddon's carpet anemones (Stichodactyla haddoni). How they used to be far more abundant before the 2007 mass deaths. They can live for 100 years or more, Dr Dan explains. And such long-lived animals take longer to return after a catastrophic event like the mass deaths. He is heartened, however, to note that many small Carpet anemones have returned to the shores.
Dr Dan finds a suspicious bump in the sand that seems to hide a moon snail. Kok Sheng digs it out and...
It's not a moon snail. It's a slimy Naked moon snail (Sinum sp.). Which is in the Moon snail family but has a huge body that cannot completely retract into its flat thin shell. As Kok Sheng was showing the snail to the rest of us, the snail started to seriously elongate! Eew!
Kok Sheng had found some dugong feeding trails! There are short parellel ones, in approximately the same area where last year, Dr Dan saw what might have been a dugong feeding at high tide. Today, there were several dugongs feeding side by side? A mama and her baby? So much more to find out about Chek Jawa.
There were also lots of Cake sand dollars (Arachnoides placenta) on the shore. And many of them had been pecked by birds. We know because there were lots of bird prints around the pecked sand dollars. Dr Dan is keen to check on the variety of echinoderms on Chek Jawa. We saw one each of these Ball sea cucumbers (Phyllophorus sp.), Thorny sea cucumbers (Colochirus quadrangularis) and smooth sea cucumber.
Hurray, we found a small patch of Button snails (Umbonium vestiarum). Cindy also found a Lined moon snail (Natica lineata). Earlier on, we saw some Ball moon snails (Polinices didyma).
Other animals we saw included a Noble volute (Cymbiola nobilis), many flower crabs (Portunus pelagicus), Dr Dan found a Mama Stone crab (Myomenippe hardwickii). There were many Striped hermit crabs (Clibanarius sp.) and peacock anemones (Order Ceriantharia) and Kok Sheng found a Common sea pen (Pteroides sp.). We saw lots of different kinds of tube worms and the seagrasses were doing well. We also saw several eagles, heard the Straw-headed bulbul and Wild junglefowl, and saw the Great-billed heron.

We had a quick look at the mangroves along the boardwalk and a large dragonfly is spotted.
Today I noticed large insects around the flowering Nipah palms (Nypa fruticans). And it seems the ball shaped female flowers are attracting insects too. Usually, I only see lots of insects around the sausage shaped male flowers.
We decided to check on the Hornbill nest box before leaving and are lucky to meet Alan there. As well as Papa hornbill feeding Mama hornbill who is sealed up the nest box!
Unlike other birds that build nests out of sticks, the Oriental pied-hornbill (Anthracoceros albirostris) usually nest inside a hole in a tree. The mother bird will seal herself up in the hole, with the help of the father bird, leaving only a narrow gap for her to stick out her huge bill. While papa feeds her, mama stays in the nest to lay eggs and raise her young. The seal is only broken when the babies are ready to fly.

Before feeding her, Papa hacks up stuff. I guess since he has no hands, he just has to swallow what he can find and regurgitate his finds to feed his mate and young. The artificial nest boxes set up by NParks are so successful there is a population boom of these birds now. The nest box includes cameras outside and inside the box, to better document and learn about these delightful birds.
As we were leaving Chek Jawa, Mama wild boar (Sus scrofa) and her two young ones said hello.
The team had to rush off for a talk by N. Sivasothi in the afternoon. So we bid them a quick farewell. Thanks to Alan and Cindy of NParks for facilitating the trip, and Robert and Kok Sheng for helping to share Chek Jawa with our guests. I'm hoping to meet Dr Dan and his team again later this week to share Pasir Ris mangroves with them!

Kok Sheng shared more about this trip on his blog!

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