I think that the breakwaters by the side of the Marina Barrage was built to prevent erosion of the beach fronting the barrage. But it turned out to be a great place to study the post breeding behavior of families of the Little Terns, Sternula albifrons. Besides the Black-naped Terns, Sterna sumatrana, the Little Tern is the only other tern that breeds in Singapore, although we had some sporadic records of the Bridled Terns, Onychoprion anaethetus, breeding at Horsburgh Lighthouse.
Since early July, a few adult terns were using the breakwaters to teach their juveniles flying and survival skills of catching fish in the open waters. As the juveniles are not able to fly for long periods, the breakwaters is a convenient place for them to come in for a rest.
At first the parents will bring back the fish for the juveniles and then gradually entice the juveniles to follow them out to fish at sea. The parent birds will catch the small fishes and dropped them back to the water for the juveniles to practise fishing . By the end of July, a few older juveniles were seen fishing on their own having mastered the art of finding and catching the small fishes from the parents.
Unlike the period before the chicks fledged, the parent terns at the breakwaters were very tolerant of intruders. They allowed the photographers to come close knowing that the juveniles were able to fend for themselves. Those of us that tried shooting the young chicks at the open grasslands will tell you the ferocity of the adult terns dive bombing every intruder including House Crows that get too near to their chicks.
This in turn allow us to get some stunning photos of these terns in flight, fishing, feeding preening and fighting for food in a natural surrounding. This will not be possible if not for this breakwaters which is just outside the CBD.
Reference: A Field Guide to the Waterbirds of Asia. 1993 The Wild Bird Society of Japan.