1. The documentation:
A pair of Olive-backed Sunbirds (Cinnyris jugularis) was seen landing on a patch of vegetation at Toh Yi Drive on 14th March. They were fighting during the flight and continued fighting when they landed. The female sunbird was dominating the fight, gripping the male’s wings with her feet to hold him down and pecking his head repeatedly. After about 10 minutes of pecking, the female suddenly flew off, leaving the male stunned and motionless for about 10 seconds before he flew off to a nearby tree.
Derrick Wong was there with a group of photographers observing the Lineated Barbet and managed an excellent image of the aggressive female attacking the male sunbird (above). MeiLin Khoo also happened to be around and produced a video clip of the entire drama (below).
Derrick Wong & MeiLin Khoo
16th March 2019
2. Comments by Dato’ Dr Amar-Singh HSS, birdwatcher extraordinarie:
“Thank you for allowing me to have a look and respond to this interesting observation and lovely image by Derrick Wong and excellent video by MeiLin Khoo. I considered some possibilities for a female Olive-backed Sunbird attacking a male of the same species (intraspecific conflict).
a. I wondered if our ID was incorrect and if it was actually a rival male in eclipse plumage? But there is nothing to suggest this; it’s a female.
b. I then considered if it was a juvenile bird demanding food from an adult parent? But the image shows an adult female. I have in the past seen adult birds still demanding food from parents, especially if these was some apparent intellectual impairment that diminished their ability to forage. Unlikely here looking at the keen eye and demeanor of the attacking female.
c. So I was left with the possibility that this adult male (from a different family unit) had strayed too close to this adult female’s nest and she was defending her nest. Wells, D.R., 2007 (The birds of the Thai-Malay Peninsular. Vol. II, Passerines. Christopher Helm, London. 800 pp.) does indicate that Olive-backed Sunbird parents can aggressive attack other passing creatures (even bees). I see no reason for intraspecific conflict not to occur if a perceived rival strays near a nest.
d. I doubt she was demanding the male mate with her or was berating him for failing to support a brood (as we might in humans).
“Please also note a previous BESG report of a male Olive-backed Sunbird attacking female for unexplained reasons: LINK.
“I could not find any reference to such sunbird conflict behaviour in ‘Clive F. Mann, Robert A. Cheke, Richard Allen, Sunbirds: A Guide to the Sunbirds, Flowerpeckers, Spiderhunters and Sugarbirds of the World. 2001. Helm Identification Guides’.
“I have taken the liberty of cc this email to Clive Mann for an opinion.”
Dato’ Dr Amar-Singh HSS
Ipoh, Perak, Malaysia
17th March 2019
3. Opinion of Dr Clive F Mann FLS, ornithologist and contributing co-author of the series del Hoyo, J., A. Elliott & D. A. Christie (eds.), Handbook of the birds of the world. Lynx Editions, Barcelona on sunbirds, flowerpeckers…
“Very interesting observation and lovely photo. Thanks for this.
“Amar has carefully analysed all possibilities and I think (c) is by far the most likely. Intraspecific aggression is not uncommon in a whole range of species, particularly near a food source or nest. In other words within a ‘territory’. We tend to be biased and think that the aggressors are usually male. Often this is because we don’t know the sex of the aggressor. Females of some species are known to help defend a territory/nest and I guess that’s happening here. Sometimes a territory is only the immediate surroundings of the nest.
“There’s so much to learn about bird behaviour still, particularly in the tropics.”
Dr Clive F Mann FLS
17th March. 2019
This post is a cooperative effort between Birds, Insects N Creatures Of Asia and BESG to bring the study of birds and their behaviour through photography and videography to a wider audience.