If you spot a swan bobbing gently in a reservoir or canal, take a closer look. There could be a lot more going on beneath the surface than paddling feet.
National University of Singapore (NUS) researchers have kitted out a plastic decoy swan with equipment and robotics so it can float around testing water quality, transmit findings wirelessly, return on its own to a charging dock and even call for help if it is nicked.
Such decoys are used in Canada to stop noisy, messy geese from landing on ponds, but NUS researchers performed a little surgery on one to add electronics to its innards, and Global Positioning System and wireless sensors to its head.
Its undercarriage bears a cylinder that can be fitted with sensors for chlorophyll, pH, dissolved oxygen and any other water-quality measure desired.
Lead researcher Mandar Chitre, head of the Acoustic Research Laboratory at the university's Tropical Marine Science Institute (TMSI) and an electrical and computer engineering assistant professor, said the project stemmed from a need to monitor the quality of freshwater bodies.
The swan saves manpower, he said. It can also provide measurements over time and over a large area, compared with, say, having fixed sensors or sending out people to test water from a boat.
The swan is also easier to maintain and cheaper than submerged robots, added research associate Koay Teong Beng.
The project is among dozens of efforts that have propelled Singapore into the top ranks of the global water research community.
In a survey by consultancy Lux Research earlier this year, NUS came in No. 1 in water research and Nanyang Technological University (NTU) second, among about 400 universities and institutes worldwide.
Since 2006, Singapore has committed $470 million to grow the water sector. NTU's Nanyang Environment and Water Research Institute this year received an extra $132 million until 2016 from the industry, public agencies and grants from funding bodies.
The NUSwan (New Smart Water Assessment Network) project by the NUS Environmental Research Institute and the TMSI evolved from existing work on underwater autonomous robots.
The swans can paddle about at a top speed of two knots, or a little over 3.5kmh, and currently cost some $20,000 to $30,000 to develop. But the cost could drop when they are produced commercially.
The long-term vision is to have a flock of such robots that can also be used to map out coral reefs and monitor their health, said Dr Chitre.
But what about the fact that swans are not native to Singapore? "If you want to increase the biodiversity, you can use a different species," he quipped.