Tuesday, January 22, 2008

Diplacodes nebulosa; Rhyothemis triangularis; Lesser Whistling-duck

Another odonate survey with the gang, this time to the ponds of Marina East. The habitat is dominated by thin grass-like vegetation. Not very sure what plant it is but most probably belongs to the Cyperaceae family. The water itself is full of brownish algae and there’s a slight smell typical of eutrophic waters.

Nevertheless, this is an excellent habitat for odonates. They are in high abundance and are very active thanks to the warm morning sunshine. The most numerous species is Diplacodes nebulosa. They are very distinct due to the dark tips on their wings. All the males are defending a small territory and chasing each other, zipping all over the water surface.

The most striking dragonfly there has to be Rhyothemis triangularis, aptly named due to the deep metallic blue triangular patch on its hind wings. Dragonflies from the genus Rhyothemis characteristically have short abdomens with broad hind wings. Some of them are quite common in open countries or streams in swampy forest. R. triangularis is common and widespread in Asia. However in Singapore they are rather uncommon as habitats akin to the Marina East ponds are few and far between.

But odonates are not the only creatures inhabiting the ponds. From afar, a Lesser Whistling-duck (Dendrocygna javanica) made an appearance. This is a nationally vulnerable bird. Once again habitat loss is the main cause as freshwater ponds are destroyed when urbanisation encroaches. This bird has an estimated population of 250 in Singapore.

As we left Marina East, I sensed a “melancholy in the wind and sorrow in the grass” (Charles Kuralt). How much longer will this location remain as it is? Its neighbour at Marina South is already morphing into the Integrated Resort. Rumour has it that Marina East will become a golf course. “Another golf course?!” Tang sighed.

Perhaps we could get the developers to build the golf course while preserving this small nature haven? My mind begins to sparkle…




Pictures taken at: Marina East, January 2008.


References:

Orr, A. G., 2005. Dragonflies of Peninsular Malaysia and Singapore, Natural History Publications (Borneo) Sdn. Bhd, Malaysia.

Wang, L. K. & C. J. Hails, 2007. ‘An annotated checklist of the birds of Singapore’, The Raffles Bulletin of Zoology, Supplement 15: 1-179.

Sunday, January 06, 2008

Purple Swamphen

We spent a relaxing Christmas afternoon in laidback Kranji countryside. After a sumptuous lunch, we headed to the farms dotting the area and as the sun began to set, we took a leisurely hike towards the Kranji Marshes.

The scenic Kranji Marshes hug along much of Kranji Reservoir’s perimeter. Marshlands are an increasingly rare habitat in Singapore as many have been lost to urban development.

As we took in the view, a series of loud chuckling and cackling greeted us. Out of a sudden, two dark purplish-blue birds with bright red bill emerged from the water vegetation. What a fortune! Its the unmistakable Purple Swamphens (Porphyrio porphyrio). I’ve previously only caught a glimpse of this elusive bird a year back so this was an excellent Christmas present from Mother Nature. Not only did the birds made an appearance, one of them was foraging uninhibitedly about 30metres away.

Purple Swamphen is a member of the Rail family which also includes the more common White-breasted Waterhen (Amaurornis phoenicurus). They inhabit mostly swampy and marshy habitats. These birds have a clearly distinguishable robust stout body, short tail and are rather weak fliers. Their huge red bill, red frontal shield, red legs and purplish-blue plumage make them one of Singapore’s most attractive marshland birds.
Purple Swamphens have a very conspicuous white undertail covert. The birds will constantly flash this white rump patch by jerking their tail up and down. Research suggests that this behaviour is a form of prey-predator communication whereby a bird’s state of alertness is communicated to a potential predator, thus discouraging the predator from a vigilant prey. Perhaps that was exactly what the bird was trying to tell us that Christmas afternoon. We certainly would not have the heart to harm such a fine-looking creature.




Pictures taken at: Kranji Marshes, December 2007.



References:

Alvarez, F. 1993. ‘Alertness signalling in two rail species’, Animal Behaviour, vol. 46 (6), pp. 1229-1231.

Robson, C., 2000. A Field Guide to the Birds of South-east Asia, New Holland Publishers (UK) Ltd, London.