Slaty Flowerpiercer’s feeding strategy to steal flower nectar

“It was with great luck and amazement that I was able to observe the feeding strategy that was being practiced half a world away in Costa Rica. My first encounter of this was in Singapore along my balcony when an Olive Backed Sunbird (Cinnyris jugularis) pierced the base of the Episcia cupreata ‘Acajou’ flower to get at the nectar LINK.

“In Costa Rica’s Valley of San Gerardo de Dota, specifically at the Sevegre Lodge, the same phenomenon unfolded before me. This time it was the Slaty Flowerpiercer (Diglossa plumbea) that was stealing nectar. However, the tool used was slightly different. If you were to observe closely, the lower mandible is slightly upturned, and the longer upper mandible has a downward pointing hook at the tip (above).

“What happened was that the bird would first anchor itself with the upper mandible’s hook to the base of the flower (above). It then proceeded to puncture the base of the flower using the lower mandible. This was helped by a few quick twists and turns of the head. This small opening allowed the bird to insert its tongue into the flower so as to extract the nectar.

“This is an unconventional method of taking nectar from a flower, often termed as nectar stealing. Used by native birds to exploit nectar from non-native flowers, the process does not help to transfer pollen from one flower to another.”

K C Tsang
Singapore
26th March 2014

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