I have observed this behaviour by Spectacled Spiderhunters Arachnothera flavigaster a number of times; the latest this week. It is most often seen at a feeding sources, fruit or nectar tree, with many other spiderhunter species around.
On 25 June 2024, at least 7 spiderhunters were feeding on the fruit of the Macaranga bancana – 3 Spectacled Spiderhunters, 4 Yellow-eared Spiderhunters (Arachnothera chrysogenys) and 2 Grey-breasted Spiderhunters (Arachnothera modesta). Birds were coming and going so it is possible that numbers were higher.
The Spectacled Spiderhunters, as usual, were behaving very territorial over the fruiting source (competitive feeding) and frequently chased other spiderhunters and bulbul away. Twice I saw an adult Spectacled Spiderhunter behaving like a typical juvenile bird begging for food – alight on a branch, wings outspread, fluttering wings, with loud calls. No feeding of the bird occurred.
There are four possible reasons for this behaviour:
1. Food-begging by a juvenile or immature bird – but the birds look like adults to me.
2. Courtship – Wells (2007) reports similar behaviour seen before copulation, however I did not observe any mating. In the past I have observed the similar behaviour as part of the courtship of Brown-throated Sunbirds Anthreptes malacensis and Ornate Sunbird Cinnyris ornatus.
3. Mobbing of a presumed threat – but I did not see any predator or threat
4. Aggression towards other birds to protect food sources – I suspect this is the most likely reason.
The image below shows a bird using a branch to manipulate a Macaranga bancana fruit to feed on. First time I have observed a Spiderhunter doing this with a food source.