Oriental Pied Hornbill and papaya

on 25th December 2009

The papaya trees (Carica papaya) in Tan Teo Seng’s farm in Johor, Malaysia are in fruits the year round. To enjoy the fruits, he has to be one step ahead of a family of Oriental Pied Hornbills (Anthracoceros albirostris). These birds regularly visit the trees, perching on the long leaf stalks to invariably cause them to collapse due to the birds’ weight.

Young green fruits are left alone. But when a fruit starts to turn yellow, the hornbills will check out its state of ripeness with the sharp points of their massive mandibles. In the process the birds leave characteristic markings on the yet-to-ripen fruit surface (below left).

The hornbills return daily to monitor the fruit’s ripening. And only when the fruit is fully ripe can the hornbill break into the fruit to peck off chunks of the ripened flesh. First a small opening is formed as the hornbill works its way into the flesh (above centre). This opening will widen as the sharp mandible tips steadily gouge the flesh to be swallowed with a flick of the hornbill’s head.

The fruit is never eaten in its entirety but abandoned after about a quarter is consumed (above right). The remaining fruit is left to other smaller birds like mynas, starlings, bulbuls, orioles, etc. to enjoy.

Birds generally have the best vision among the vertebrates. They also have well-developed colour vision. They have poor sense of smell as well as sense of taste. Hornbills presumably are no exception. Thus it can be assumed that they know when the papaya ripens but are unable to gauge the degree of ripeness by smell. They have to resort to testing the softness of the fruit by probing with their mandible tips.

Images by YC.

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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