Jerdon’s Baza moulting

on 22nd May 2009

Choy Wai Mun of Penang, Malaysia was visiting Taman Negara in the state of Pahang on 2nd May 2009 when he noticed an adult Jerdon’s Baza (Aviceda jerdoni) circling overhead. The raptor was flying low above the forest canopy along the jeep track around Sungei Relau before flying off into the forest.

Wai Mun managed to record a few images of the raptor in flight and in the comfort of his home noted that the bird was missing a few flight and tail feathers. It was in moult.

As seen from the image above, the primaries are apparently at various stages of being replaced and possibly with one or even more missing. However, there are no obvious moult gaps. Large moult gaps on the wings are not usually seen, as otherwise flight will be impeded.

Unlike the wings, the tail shows a very obvious gap, towards the left half. More than one tail feathers had been shed and yet to be replaced. This will not impede flight, maybe only steering.

A new feather may take weeks to a few months to be fully replaced, depending on the species.

The Jerdon’s Baza is a resident of Malaysia but a rare passage migrant to Singapore.

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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