My pioneer visit to the Mandai Mangrove was focused mainly on the assemblage of trees and shrubs, wanting to understand how trees aid sedimentation. However, as the old saying goes, ‘one does not see the forest for the trees’. Subsequent trips highlighted that this muddy world was in fact teeming with wildlife!
Personally, I found the avifauna and Malayan Water Monitor Lizard (Varanus salvator) highly intriguing (and entertaining) to observe. But this blog post shall focus on the former.
In lectures, we learnt about the competitive exclusion principle that predicts coexisting species will have different niches. Competition is one factor that significantly influences the niches of species. They have short-term ecological effects whereby niches of species are restricted to realized niches whilst long-term effects occur when fundamental niches are altered.
At the mangrove, competition results in different bird species occupying different zones – vegetation cover, mudflat and shallow streams. Therefore, different tactics are employed in capturing prey.
Little Herons (Butorides striatus) prefer hunting from vegetation cover near shallow waters as vegetation provides ideal perches when plunging into the water to capture prey. Most remarkably, they do bait fish by dropping a leaf onto the water surface (Strange, 2000).
Conversely, the Little Egrets ( Egretta garzetta) are hunters which stalk prey in shallow waters. They tend to stand on one leg and stir up mud with the other to alarm prey. Also, they do stand on one leg and wave the other bright yellow foot over the water surface to lure aquatic prey! Indeed, I have observed them successfully catching fishes using this technique!
However, the Grey Heron (Adrea cinera) are the unarguably the most patient hunters, capable of standing motionless for hours (Strange, 2000). This individual was perched on a wooden stilt for an hour before being disturbed by the Marine Patrol guardboat.
And finally, a whole range of other birds like the Ashy Tailorbird (Orthotomus ruficeps), Pink-necked green pigeon (Treron vernans) thrive.
So there! Singapore mangroves are really quite intriguing if you dare step out of your comfort zone and into the mud.
Credits: All pictures posted are courtsey of my brother 🙂
Morten Strange, “A Photographic Guide to Birds of Malaysia and Singapore: including Southeast Asia, the Philippines and Borneo”, Periplus, 2000
Navjot S. Sodhi, Johanna P. S. Choo, Benjamin P. Y.-H. Lee,K. C. Quek and A. U. Kara (1997). Ecology of a mangrove forest bird community. The Raffles Bulletin of Zoology 45(1): 1 – 13