Chinese Pond-heron In Bishan Park

posted in: Heron-Egret-Bittern, Interspecific | 1

“I was on my way to Bishan Park (renamed as Bishan-Ang Mo Kio Park now) for my cycling exercise 3 days ago (18 Mar) when my attention was drawn to a flock of birds in an open grass field outside the Park and adjacent to a secondary school. It had been raining for two hours and stopped not too long ago. With naked eye I could see 3 Little Egrets (Egretta garzetta) and about 10 Javan Mynas (Acridotheres javanicus) scattered over the field foraging (above), obviously for the numerous earthworms that emerged from the rain-soaked soil for fresh air. Then a white bird took flight from one spot and landed in another spot nearby, and I told myself that there were 4 egrets then. However, as I scanned the field again and again to recount the number of egrets, I could only see 3.

“With my camera which doubles as a monocular, I soon discovered that I had encountered ‘new’ birds. With the help of Oriental Bird Images Database LINK and our BESG blog titled “Chinese Pond Heron and its status” LINK, I realised that the 3 birds in the video were pond herons. The first one that appeared in the video showed early days of assuming breeding plumage with the feathers on the back turning dark, but there were insufficient changes on the head and neck to identify it as a ‘Chinese’ or a ‘Javan’. For the second one, with the full breeding plumage of chestnut or maroon coloured feathers on the head and neck, it was clearly a Chinese Pond-heron (Ardeola bacchus). As for the third one in non-breeding plumage, it was impossible to confirm its identity. And the mystery of the disappearing egret was solved when the video showed the white wing feathers of the herons when they fly.”

Note: The accompanying image indicated the locations of 2 pond herons. They were discovered after I scrutinised the image on the computer monitor.

Sun Chong Hong
Singapore
21st March 2012

One Response

  1. Tou Jing Yi

    The Pond Heron is in fact a special one, due to its white wings, it is very obvious in flight but at rest, the back feathers will cover the majority of the white at rest, the first surprise to me as well when I first saw these obvious white birds disappearing at perch, an excellent camouflage strategy. They are previously placed together with the Cattle Egrets under the same genus, showing that they are probably in fact not very far away from true egrets.

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