“In non-breeding plumage, different species of pond-herons are similar in appearance and are virtually indistinguishable from one another. The only way to differentiate different species of pond-herons is when they are in breeding plumage. In Singapore, mid-February to late April is the best time of the year to check and identify pond herons. During this period, just before migrating back to their nesting grounds, to attract partners, pond-herons will develop breeding plumage – colours unique to each species. As plumage develops gradually, the unusual sight of partial breeding plumage to glorious sight of full breeding plumage can be discovered.
“On 28 Apr 2012, I made a repeat visit to Lorong Halus to check on the Javan Pond-heron (Ardeola speciosa) that had developed breeding plumage. This individual had been in the vicinity since mid-February 2012 and had been photographed by many photographers. The Javan was not there that day. The migratory species that were normally seen there were gone too. The recent hot weather could have triggered these migrant species to get back on their return journeys. Disappointed at first, my disappointment turned to excitement when a solitary pond heron with an unusual plumage was spotted (above). The plumage was neither the familiar Chinese nor the rare Javan. I managed a few record shots before the bird flew out of sight; spooked by an approaching passer-by. Could this be an Indian Pond-heron (Ardeola grayii)?
“From the description of the breeding plumage in Birds of Southeast Asia by Craig Robson:
• Chinese: Chestnut-maroon head/neck/breast, blackish-slate mantle/scapulars (above left)
• Javan: Buffish head/neck, deep cinnamon-rufous breast, blackish-slate mantle/scapulars, white head plumes (above right)
• Indian: Brownish-buff head/neck/breast, rich brownish-maroon mantle/scapulars, long white head plumes
“Based on that description, this pond heron matched the Indian except for the white head plumes, which were not visible (below left).
“In the National Parks Board’s website, the Chinese Pond-heron (Ardeola bacchus) and Javan Pond-heron are listed as ‘Common Winter Visitor’ and ‘Rare Accidental Visitor’ respectively in the pocket checklist of the birds of the Republic of Singapore (2007). The Chinese Pond-heron is listed as ‘Uncommon Winter Visitor’ while the Javan is not listed in An annotated checklist of the birds of Singapore (2007) in the same web site. The Indian Pond-heron cannot be found on both lists. Neither is it listed in Birds of Singapore LINK
“Images of the 3 species are attached for comparison. Please note part of the bill turning blue for both Chinese (below left) and Javan (below right) pond-herons. The Indian Pond-heron (if ID is correct) may be at an early stage of breeding plumage as it still lacked the blue in the bill. The absence of head plume could be due to it being hidden from view or it may not have developed. Images of the Javan were captured on 26 Mar 2012 while those of the stationery Chinese was captured on 6 Apr 2012.
“How many species of pond herons can a birder see in Singapore? The answer, many years ago, used to be: only one. Since 2007, the answer has changed and increased to two. In the not too distant future, the answer could well be three.”
Kwong Wai Chong
5th May 2012