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Olive-backed Sunbird: Sipping nectar from flowers of Scarlet Spiral Flag

on 31st July 2018
Male Olive-backed Sunbird accessing nectar from the top of the flower.

The feeding behaviour of Olive-backed Sunbirds (Nectarinia jugularis) in a patch of Scarlet Spiral Flag (Costus woodsonii) was posted earlier – see HERE. It shows how the male, female and male eclipse (pre-adult, non-breeding male) accessed flower nectar. This post provides details of how the three categories of sunbirds sip nectar from the flowers. The video below shows the different sunbirds taking nectar from flowers at close range.

The beginning of the video shows a rare scene of an adult male probing the flower from the top of the flower. This is the conventional way of nectar harvesting. As the bill enters the flower, it passes through the ring of anthers to the flower base where the tongue will collects the nectar. As the sunbird leaves the flower to visit another, its bill, dusted with pollen will transfer some to the stigma of the next flower – see HERE for details of the flower.

Male Olive-backed Sunbird robbing nectar.

For whatever reasons, most of these sunbirds fail to collect nectar this way. Instead, they pierce through the base of the flower petals to short-cut the process. In this way the sunbirds are not helping in the pollination of these flowers. Such nectar robbing or stealing has become popular with the Olive-backed Sunbirds.

Olive-backed Sunbirds similarly rob nectar from Ornamental Banana (Musa ornate) flowers LINK. But in this case the flowers are longer than the bill of the sunbirds. Not so in the case of flowers of Scarlet Spiral Flag.

Male eclipse (sub adult) Olive-backed Sunbirds similarly rob the flower of its nectar.

Pre-adult males (male eclipse) similarly rob nectar. These are the young sunbirds whose breeding plumage has yet to be fully formed – the blue-black forehead, throat and breast have yet to be formed. Only patches of black can be seen on the yellow belly. Depending on how young these male eclipse is, it may show confusion on how to access the flower nectar.

Early male eclipse Olive-backed Sunbird looking confused…

Male eclipse with blue-black stripe at the centre of the throat appears to be more experienced than the younger male eclipse with only slight blue-black patch on the throat. The last segment of the video shows this young male spending a long time puzzling on how to access the nectar.

YC Wee
Singapore
16th July 2018

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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