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PURPLE HERONS – ADVERTISEMENT DISPLAYS

on 10th January 2013

“In early December 2012, a small colony of 25–30 Purple Herons (Ardea purpurea) was observed as they roosted up amongst the contiguous crowns of mature raintrees (Albizia saman) in Perak, Peninsular Malaysia (above).

“This heronry was a hive of activity, as birds regularly flew in and out of the treetops, leaving for and returning from their feeding sojourns. There was also constant communication between the members of this colony, as multiple cues were being sent to each other in the form of various displays. The intentions of such advertisement displays may be to:

(a) pronounce its claim over a particular nest-site,
(b) ensure the neighbours maintain a respectful distance,
(c) advertise its attractiveness/fitness to the respective breeding partner.

“In this heronry, a vast majority of the birds (80–90%) were adults adorned with breeding plumage in all their splendour. The base of the bills also took on a reddish hue.

“One of the most common gestures was the erection of its head and neck feathers (above). This may be accompanied by the inflation of the throat region.

“The next display may be referred to as the ‘Snap’, as defined by Kushlan (2011). With head and neck feathers upright, the neck is extended forwards and downwards smoothly. With legs bent, an abrupt snapping of the bill accompanies the expanded throat (above). This display is mostly directed at immediate neighbours.

“The most conspicuous display may be referred to as the ‘Stretch’, which is a typical courtship behaviour among herons (Kushlan, 2011). In the purple heron, the entire body slowly adopts an almost vertical posture, with the bill pointing and rising skywards (image 4). We wish to introduce an alternative term of ‘Spearing the Sky’ to describe this yoga-like pose. Often accompanying this display is the erection of the elongated plumes of its lower neck and scapulars. When it reaches the apex of its extension, the throat is usually puffed up and there may be brief clappering of the bill.”

“A brief video clip of this ‘Stretch’ display may be previewed above.”

Subaraj Rajathurai & Dr. Leong Tzi Ming
Singapore
19th December 2012

REFERENCE
Kushlan, J. A., 2011. The terminology of courtship, nesting, feeding and maintenance in herons. [online: www.HeronConservation.org]

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.

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