Howard Banwell was at the observation tower of Singapore’s Sungei Buloh Wetland Reserve recently when he documented a male Olive-backed Sunbird (Cinnyris jugularis) indulging in comfort behaviour.
The sunbird was perching upright on a branch of a tree with his iridescent blue-black frontal fully exposed (above left). All of a sudden it turned his head around nearly 180º and started preening his upper wing coverts (above right).
Next, he worked on his primary flight feathers. Grasping a feather near its base, he nibbled along the shaft towards the tip (above left). This helps to remove dirt, smooth the barbs so that they can lock together. Working the inner primaries was relatively easy but there was a need to stretch his neck to the limit when dealing with the tips of the outer primaries (above right).
Preening the secondary flight feathers which are nearer the body was also relatively easy (above left), even though there was a need to bend the head down a little bit more when the tips were involved (above right).
In between preening there was time to take a break, to extend his tongue to the fullest (above left) and to call (above right).