Saturday, 25 September 2010

a short hike into MacRitchie

After dropping Lex off at the vet for his weekly acupuncture, I took off for Venus Drive and hiked for about 4km into one of the many trails within MacRitchie. I had hoped to make it as far as the tree-top walk, but unfortunately, it was too far for the amount of time that I had.

One of the more common findings was the Common Parasol dragonfly (Neurothemis fluctuans). This is a very common species which can be found in most parks especially those with water bodies like streams and ponds. They are relatively easy to shoot because they are not as nervous and tend to hover around the same areas.

I also came across quite a few male and female Archduke butterflies (Lexias pardalis dirteana) fluttering around quite lowly near the forest floor. The species which belongs to the family Nyphalidae, exhibits sexual dimorphism where the male is black with greenish blue wing margins whilst the female is dark brown with yellow spots on both wings. The Archduke is a powerful flyer and is difficult to capture on the wing. It is essentially a jungle butterfly and is relatively common in Singapore's lowland forests. It is attracted by rotting fruit (pineapple and guava are favourites) and can be found feeding greedily on these fruits on the forest floor. More information pertaining to the Archduke can be found here .

Another interesting and fairly common sight is the common sun skink (Eutropis multifasciatus). These shy reptiles are widely distributed throughout South-East Asia and can be commonly found basking in the sun along forest tracks or on tree trunks. They are mainly terrestrial and diurnal and feed mainly on insects. Normally, they would scuttle away suddenly as you get close to them. However, this particular skink ran out of the bush into the open grass not far from where I was standing, presumably to get away from a predator. It was rare to see them out in the open like that, so I managed to get quite close to it without scaring it away and getting quite a few shots.

But the most interesting find for the day had to be the Spiny Terrapin (Heosemys spinosa). This is a fairly uncommon species (Famil: Geoemydidae) in Singapore which is usually found on the forest floor, well-camouflaged amongst the leaf litter. It usually forays to streams and puddles and feeds on fallen fruits and other vegetation. The origin of its common and specific name is immediately apparent from the sharp, pointed, spiky-edged carapace, and spiny keel, of this unique turtle, also known as the ‘cog-wheel turtle’. There are also smaller spines on the pleural scutes, creating the effect of a walking pin cushion. It is thought that this spiny ‘armour’ acts as a deterrent to predators, such as snakes. However, this unmistakable, strongly-serrated carapace edge and spiny keel become worn down and are lost with age, so that larger individuals are much smoother than juveniles. The carapace is brown with a pale streak down the central keel, and the head and limbs are greyish-brown, usually with a yellow to red spot behind the eye and similar-coloured speckling on the legs.

Monday, 20 September 2010

the tiger and the 'unicorn'

Two stories dominated last week's headlines in the nature world. One involved the discovery of the lost tiger population in Bhutan while the other was the re-discovery of one of the world's rarest mammals.

News of the former can be found on today's edition of BBC's Earthnews . The BBC natural history camera crew has, following reports by villagers, managed to film a pair of large tigers in the Bhutan highlands. This discovery has stunned experts because it confirms that tigers can live and breed at higher altitudes. Furthermore, it is the only place on earth known to have tigers, leopard and snow leopards all sharing the same valley. Such a discovery is important and crucial as it is a means of saving the species from extinction by creating what is known as a "tiger corridor". Essentially, this involves linking up many of the surviving tigers to encourage breeding so as to bolster the genetic diversity of those surviving. With the discovery of this pair in Bhutan, the Himalayas can now be included in the tiger corridor along with Myanmar, Thailand, Laos, Cambodia and Malaysia.

The other great discovery is that of the Saola in Laos, sometimes called the Asian 'Unicorn'. This animal was captured by villagers in Laos in August but sadly, died after Laotian conservation authorities confirmed the ID of the mammal. While the death is unfortunate, the discovery is important because it confirmed that this species was alive and that it still occurs in the area where it was caught. This is the first confirmed sighting of a Saola since 1999 when remotely triggered cameras took images of one in Laos. It resembles an African antelope with 2 large horns, but it is more closely related genetically to wild cattle. It was first discovered in 1992 in South Asia and biologists estimate that there are probably fewer than a few hundred Saolas roaming the Annamite Mountains of Laos and Vietnam.

This capture highlights the importance of Laos to global wildlife conservation since, like the Saola, several other rare endemic species are found almost nowhere else in the world. Hopefully, more will be done to do what is necessary to preserve and protect what's left of this species.

Wednesday, 15 September 2010

a visit to sungei buloh

Determined to make my moneys worth, I ventured out to Sungei Buloh Wetland Reserve on Sunday to shoot with the rented Canon EF 70-200 f/2.8 L IS II USM zoom lens.

Sungei Buloh is an ecological jewel located in the North-Western part of Singapore facing the Johor Bahru. Officially opened as a nature park in 1993 and gazetted as a nature reserve in 2002, this reserve consists of 130 ha of wetlands and mangroves. Given its global importance as a stop-over point for many migratory birds escaping the harsh winters in the northern hemisphere, the reserve is included in the East Asian Australasian Shorebird Site Network. It is also listed as an ASEAN Heritage Park in 2003.

The reserve is renowned for its rich biodiversity and a hot favourite amongst many avian enthusiasts as it is a major stop-over for all sorts of birds during the migratory season between the months of September and March. Some of the birds one many encounter in the area include the Curlew Sandpiper, Marsh Sandpiper, Pacific Golden Plover, Yellow Bittern, Cinnamon Bittern, Mongolian Plover, Common Redshank, Baya Weaver, Stork-billed Kingfisher, Emerald Dove, White-bellied Fish Eagle, White-breasted waterhen, various herons and egrets, large-tailed Nightjar and many more. A more comprehensive list of birds usually seen at the reserve can be found here .

The reserve is rich in other fauna as well and some of the stars of the reserve include a family of wild smooth-coated otters (Lutrogale perspicillata). Although it is widely distributed throughout Southeast Asia, they are considered rare in Singapore and are listed as critically endangered in the Red List due to the loss of wetland habitats. To-date, they have been sighted not only at Sungei Buloh but also in Paris Ris, Punggol and Pulau Ubin. I have personally seen two at Pulau Tekong during my NS days.

Another common resident of the area is the water monitor lizard (Varanus salvator). They are everywhere and therefore hard to miss. These reptiles can be found throughout Singapore and appear to have adapted well to urbanisation. National servicemen would tell you about the shock they get whenever they trek through our forests because these lizards will just scuttle away suddenly when threatened. The ones at Sungei Buloh are probably very used to human attention because they don't feel threatened and will just go about their business, either looking for food or simply basking under the sun. Shooting them was such a breeze.

Water monitor lizards are widely distributed throughout South-East Asia. They can grow to about 10 feet and weigh over 25kg. Because they are cold-blooded (i.e. their blood tends to match the temperature of their surroundings), they make more efficient use of food since they do not have to burn fuel constantly to keep their temperature constant. They also fair better than other reptiles of their size because they are able to maintain an almost constant body temperature by choosing appropriate micro-climates in their habitat, i.e. hiding when it is hot and in warm places when it's cool at night. They eat anything they can swallow, i.e. crabs, insects, molluscs, snakes, eggs, fish, birds, rodents and even their own kind. Like Komodo Dragons, they also eat carrion and their saliva contains hundreds of nasty septic pathogens and bacteria which may kill from infection. They are highly mobile and can swim very well. Their role in the reserve is valuable as they tend to control the population of their prey. They are also a food source for crocodiles and their young are particularly vulnerable to birds of prey and other larger birds including herons.

Some of the other animals one would normally encounter at the reserve are the long-tailed macaque (Macaca fascicularis), grey squirrels and even a family of wild boars . Also common in the reserve are snakes ; from black-spitting cobras to the reticulated python. But the noteworthy ones are the Paradise Tree Snake (Chrysopelea paradisi) and the Shore-Pit Viper (Trimeresurus purpureomaculatus). The former is considered by some to be rare though commonly encountered in a variety of habitats including mangrove, secondary forest, and parks and gardens. It is an adept climber and as with other members of the Chrysopelea genus it has the remarkable ability to glide from tree to tree. It does this by flattening the body so that the ventral surface becomes concave, and then projecting itself into the air from a high branch whilst making sinuous snake-like movements. For this reason, it is often referred to as the "flying snake".

The Shore-Pit Viper is relatively small but sinister since it has a reputation for being unpredictable and should therefore be approached with caution. Giving no warning signs, this snake will strike readily at any threat, and its powerful haemotoxic venom can cause serious illness or even kill. By day it can be found resting on low branches one or two metres from the ground, mostly in mangroves and coastal forests. Its colour can vary from a uniform dark grey or purplish-brown to a weakly-patterned brown, with a white stripe along each flank, or even greenish-yellow with dark mottling. I managed to sight just one snake which I initially mistook to be the Paradise Tree Snake. But after looking at the photos on this site , I realised that the one I saw was in fact the Striped Brozeback (Dendrelaphis caudolineatus) , the rarest of the bronzebacks in Singapore. This large species of Bronzeback, measuring up to 1.5 metres, occurs in a variety of habitats including closed forests, open secondary growth and scrubland. It is active by day, and is generally arboreal preferring to move amongst low trees and shrubs. The species is best identified on the basis of its thick black lateral stripes on a white background, and its brown dorsal surface. It lacks the black eye-stripe which is present in most other bronzebacks. The top of the head and neck are bronze.

The first sight which greeted us from a distance was this medium-sized estuarine crocodile (Crocodylus porosus) swimming towards us from the mouth of Sungei Buloh. These reptiles are widely distributed throughout South East Asia and the Pacific and quite a few have been sighted and recorded in our waters and even reservoirs. It can thrive in both brackish as well as freshwater habitats, thus making this reptile highly resilient and adaptable. Apparently, there are two or three resident crocodiles at Sungei Buloh, most of which can be seen sunning themselves on the mud-banks during low tide. This particular one I shot is quite the attention-seeker because it just appeared out of nowhere and glided towards the bridge, much to the excitement and joy of the crowd gathered there to see it. As soon as it got very near to the bridge, it made a dive into the murky green waters, causing much confusion to the excitable crowd A minute later, the crocodile surface quite some distance on the other side of the bridge and swam deeper into the estuary.

Here are some of the fauna I managed to see.

As with any mangrove area, there is a huge variety of mangrove crabs (Sesarmid) in the reserve. These include the Face-banded Sesarmine Crab (Perisesarma eumolpe), Pink-fingered Vinegar Crab (Episesarma chentongense), the mangrove tree-dwelling crab (Selatium brocki) etc. In fact, there are close to 40 species of mangrove crabs in the reserve, most of which emerge at night. Sesarmid crabs are adapted for scrambling over slippery surfaces. They have well-developed hooks on the tips of their long legs that grip these surfaces. Their bodies and legs are flattened, allowing them to squeeze deep into narrow cracks and crevices. In some species, males have larger pincers than females. Many can stay out of the water for some time.Ecologically, these crabs are known to be important. By feeding on the mangrove leaves that have fallen from the canopy, these sesarmid crabs help to initiate the breakdown of these leaves, which are otherwise difficult to decompose. Some of our Sesarmid crabs are listed among the threatened animals of Singapore. Like other creatures of the intertidal zone, they are affected by human activities such as reclamation and pollution.

And here are some photos of the typical plants one can find at the reserve. A list of plants commonly found in the reserve are set out here . I will deal with these in detail in my botanical blog .