Sun Chong Hong’s videos of the Olive-backed Sunbirds’ (Nectarinia jugularis) (male sunbird above; female below) show its method of harvesting nectar from flowers of Costus woodsonii (Scarlet Spiral Flag) is different from that of the Brown-throated Sunbird (Anthreptes malacensis).
Instead of prying open the flower, the Olive-backed Sunbird simply inserts its bill into the flower and allows its tongue to harvest the nectar.
Note that in Johnny Wee’s images (above), the Brown-throated Sunbird uses its foot to pull part of the flower towards the flowering head. This effectively forces the flower to open up, after which the sunbird uses its mandibles to keep the flower parts separate. It then pushes its head down for the tongue to harvest the nectar LINK.
The screen grabs of Chong Hong’s videos (above) show the Olive-backed Sunbirds use the foot to grab hold of the flower without pulling part of the flower inwards before inserting the bill in.
Images of flowers from a patch of these plants show most of them have puncture marks likely made by these sunbirds to reach the nectar (above).
According to Chong Hong, “My feeling is that feeding habit is also a matter of acquired experience. Most of the time sunbirds poke their bill at the base of flowers such as heliconia, but there was one occasion when I saw a sunbird poking through the flower opening.”
Sun Chong Hong (videos, screen grabs) & Johnny Wee (images)