|Remarks :||I often find that I can miss bird behaviour if I dismiss “common birds”. I was out for a long walk in my favourite forest reserve, more to build up strength than bird watching, and noticed a number of bulbul species active in the numerous Acacia tree at the forest fringe. These, I think, are the Acacia mangium trees, rather than the more common Acacia auriculiformis.
I initially thought that they were looking for animal prey and almost dismissed the activity but decided to watch for a while. I was surprised to notice that the bulbuls were actually feeding on the fruit of the Acacia. There were Red-eyed Bulbuls Pycnonotus brunneus, Yellow-vented Bulbuls Pycnonotus goiavier analis and Olive-winged Bulbuls Pycnonotus plumosus plumosus.
The fruit of the Acacia is a curled pod, initially green, turning brown-black on drying and splitting to expose a black seed and orange “stalk” (aril). YC Wee (See: Tropical trees and shrubs – A selection for urban plantings, 2003), when describing the Acacia auriculiformis, states that “The yellow stalks and black seed apparently attract the attention of birds which swallow them together, the seeds passing out unharmed to germinate all over the place”.
I must say that I never really registered this fact despite having watched birds often in Acacias and having read his book. Also documented in other bird literature, now that my eyes are open.
I can now verify that these bulbuls do feed on the black seeds and orange stalks (arils) of the Acacia mangium trees, having watched numerous feeding events.