Malaysia

Text and pictures by Izzat Ahmad Fauzi, 22 July 2017

Nectar robbing in action by adult male and juvenile Red-throated Sunbird

 

 

Cassava variety, locally known as Ubi Gajah is an ornamental plant, grown for shade cover and as natural fence. The tuber produced by Ubi Gajah is not suitable for consumption as it is very hard and the resin could cause intoxication. It produces clusters of pink colored flowers which later develop into 2 cm green fruits.  Without pruning, it will grow into a huge bush.

For the past two weeks, birders and bird photographers visited row of Ubi Gajah bush located at Hulu Langat, Selangor to observe the uncommon Red-throated Sunbird. Orange-bellied Flowerpecker and Crimson-breasted Flowerpecker were also sighted taking part in this feeding frenzy, particularly behaviour of nectar robbing by Red-throated Sunbird was interesting to me. Besides nectar robbing, the sheer number of Red-throated Sunbird observed congregating to feed on these flowers was amazing. During the peak feeding activity from 8 am to 10 am, about 12 individuals were sighted, ranging from adult male, female and juvenile (the juvenile birds were recognised by apparent orange bill gape).

From right to left: Adult male, adult female & juvenile of Red-throated Sunbird

Red-throated Sunbird is an uncommon resident in East and West Malaysia. It can be distinguished from male Plain-throated Sunbird by dark maroon-red sides of head and more red on the wing coverts. It can be found in primary forest and has been known to utilize secondary habitats. It usually frequents the canopy and crown of treesa.

Nectar robbing is achieved by making a hole in a sympetalous corolla, allowing the flower visitor to have direct access to nectar from the nectary than is possible for “legitimate” pollinators which visit the flower in the fashion for which it seems to have evolvedb. In this case, the sunbird made the hole by piercing the base of flower with its beaks. The nectar was extracted with rapid motion of its long tongue. The injured flower was left with one small hole.

The small hole on the base of flowers indicated the flowers were nectar robbed

A male with yellow pectoral tufts was also observed amongst the group. Based on Field Guide to the Birds of South-East Asia by Craig Robsonc, the yellow pectoral tufts was usually used for mating display. A pair of Red-throated Sunbirds was seen in mating display dance, where the male was hopping along the branch with female in view below.

 

 

 

 

 

 

 

 

 

I am very happy and fortunate to document this uncommon sunbird.

References:

1. Jeyarajasingam, A and Pearson A, 2012, A Field Guide to the Birds of Peninsular Malaysia and Sigapore, Oxford University Press Inc, New York.
2. Inouye, David W. 1980. The Terminology of Floral Larceny. Ecology Vol. 61, No. 5.pp. 1251-1253.
3. Robson, Craig. 2015. Field Guide to The Birds Of South-East Asia. Bloomsbury Natural History