Seed dispersal by bulbuls in Hong Kong

on 2nd November 2008

When bird-photographers and even birders make observations in the field on the fruits birds take, they could keep an eye on how the fruits are eaten – swallowed whole, pecked piece by piece, squashed the contents out, etc.

And another observation that needs be to noted is how soon and how far away are the seeds excreted or even regurgitated.

Prof Richard T Corlett, formerly of the University of Hong Kong, now back with the National University of Singapore, is keenly interested in such information. One of his fields of studies is seed dispersal and he is hoping that local birders will make such observations.

As Richard noted in his comment on bulbul eating fruits of Tabernaemontana corymbosa: “One of my postgraduate students in Hong Kong, Jacqui Weir, measured how long seeds take to pass through the guts of Chinese (= light-vented) (Pycnonotus sinensis) and Red-whiskered Bulbuls (P. jocosus) and, using radio-telemetry, how far the bird moved, on average, during the gut passage time. It turned out that the bulbuls were moving most seeds less than 100 metres, but the occasional one more than a kilometre.”

These two bulbul species are common in the degraded habitats of Hong Kong. They are fruit eaters and excellent seed dispersers, helping in plant succession of barren areas. The limitation of these seed dispersers is their maximum gape of about 14 mm. This prevents them from swallowing bigger fruits, although they are able to handle larger, multi-seeded soft fruits.

However, these bulbuls are capable of dispersing most of the wild fruit plants.

YC Wee
November 2008

Weir, J. E. S. & Collett, R.T. (2007). How far do birds disperse seeds in the degraded tropical landscape of Hong Kong, China? Landscape Ecology 22:131-140.

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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