Migratory Terns: Flocking and Communal Bathing

on 25th December 2012

“For more than a month, a flock of terns, consisting mostly of migratory White-Winged (Chlidonias leucopterus) and Whiskered (C. hybridus) terns, have been staying in and around Serangoon Reservoir. Both species are winter visitors and passage migrants; spending time here to replenish their energy before proceeding with their migratory journey further. Also present were some Little Terns (Sterna albifrons), but they seemed separate from the main flock.

“In late November 2012, just before these terns gradually disappeared from the area, I chanced upon a flocking display at around 9:30 am. Instead of flying low over the water, which was their usual behaviour during foraging, they were soaring higher and higher. As they soared higher, the initial flock of a dozen terns was met by a larger flock to merge into a single flock of more than fifty birds (top and above). This flock continued to soar and flew in unity, circling a few times over the area before disappearing into the horizon. Could this be a practice, a prelude, before continuing on their long migratory journey from our shores? Or was it the actual commencement of their migratory journey?

“On the morning just a day before this flocking display, some of the terns (about 20 of them) were bathing in a flock (above and below) . They were performing communal bathing – not in small waterholes, but in the vast water body that is Serangoon Reservoir. Flying low over the water in the middle of the reservoir, they were turning and twisting, changing directions every now and then, and taking turns to dip into the water. Each dip was brief, lasting but a second or so. This alternating flying and plunge-bathing scene was repeated multiple times. They were at it for about 3 minutes before going their separate ways – some gathering on the floating buoys to dry while others went foraging.

“One week later, in early December, most of the terns had disappeared from the area.”

Kwong Wai Chong
18th December 2012

If you like this post please tap on the Like button at the left bottom of page. Any views and opinions expressed in this article are solely those of the authors/contributors, and are not endorsed by the Lee Kong Chian Natural History Museum (LKCNHM, NUS) or its affiliated institutions. Readers are encouraged to use their discretion before making any decisions or judgements based on the information presented.

YC Wee

Dr Wee played a significant role as a green advocate in Singapore through his extensive involvement in various organizations and committees: as Secretary and Chairman for the Malayan Nature Society (Singapore Branch), and with the Nature Society (Singapore) as founding President (1978-1995). He has also served in the Nature Reserve Board (1987-1989), Nature Reserves Committee (1990-1996), National Council on the Environment/Singapore Environment Council (1992-1996), Work-Group on Nature Conservation (1992) and Inter-Varsity Council on the Environment (1995-1997). He is Patron of the Singapore Gardening Society and was appointed Honorary Museum Associate of the Lee Kong Chian Natural History Museum (LKCNHM) in 2012. In 2005, Dr Wee started the Bird Ecology Study Group. With more than 6,000 entries, the website has become a valuable resource consulted by students, birdwatchers and researchers locally and internationally. The views and opinions expressed in this article are his own, and do not represent those of LKCNHM, the National University of Singapore or its affiliated institutions.

Other posts by YC Wee

2 Responses

    1. Thanks, Amar. Yes, having personally seen this a few times, communal bathing should be a common occurrence. Just wish to share and create more awareness of such behaviour.

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