Further notes on nesting and post-nesting observations of Olive-backed Sunbird ( Cinnyris jugularis).

File photo of a pair of Olive-backed Sunbirds nest building at Labrador NR,

By Alfred Chia I wrote previously on my FB and Singapore Bird Group FB on the nesting of the Olive-backed Sunbird along the corridor of my house, see: https://www.facebook.com/540928362/posts/10158109695448363/?d=n & https://www.facebook.com/540928362/posts/10158121932008363/?d=n andhttps://wp.me/p4VGho-56X After the mysterious disappearance of the entire nest, I requested for information and feedback from readers of any similar experiences, since many will have experiences with nesting of the Olive-backed Sunbirds, it being a species that is very adaptable and will nest freely in close proximity to humans and its environs. Several readers responded and I am thankful to them. Out of eleven readers who responded, one (众生云云) had the same post-breeding experience as me in having a whole nest disappear without any trace (no debris was found) while another (MeiLin Khoo) had a pre-breeding disappearance, also without trace. Another (VirgoSG) had two nests disappearing with debris being left behind but it is unknown if these were pre or post-breeding disappearances. Clara Tan responded that hers was most probably a case of predation by a Yellow-vented Bulbul (Pycnonotus goiavier), which had been observed eyeing the nest even during the nest-building phase. It subsequently tried to prey on the chick but was unsuccessful in the first instance. However, the entire nest, together with a week-old chick, went missing soon enough. There was also not a trace of debris. Alan Owyong also contributed by sharing that he had also seen a Yellow-vented Bulbul harassing a sunbird while it was nest-building while Weijie Liao witnessed a nest being destroyed by a House Crow (Corvus splendens).Puran Kaur also had a pair of Olive-backed Sunbirds nesting in her balcony. After the chicks fledged, the nest was however left intact with no action whatsoever from the sunbirds for more than two weeks. Predation by a cat was shared by Ong PL (through Tracy Heng). Such predation is possible if the nest is low and within reach of the cat, even if it is on a tree. But predation by a cat would almost always result in a nest being destroyed entirely, with remnants of it being strewn around it. Basanthi Seetoh, who have had the honour of having more than 30 nests in her balcony over 15 years shared her experiences that used nests maybe re-use after some repairs and touch-up by the sunbird (documented) or they may strip off some parts of the old nest to build another new nest nearby. Yet another observation was made by Lim Khoon Hin of an uncompleted nest being strip apart by the sunbirds after it was hung back by the observer’s helper when it dropped due to strong winds. Every bit of debris that fell on the ground was cleared by both the male & female sunbird! Finally, Chen Eddie shares an intriguing encounter of a sunbird stealing nesting material from another sunbird’s nest. In summary, it remains a mystery how an entire sunbird’s nest can disappear without any trace. The distinct probability that it could have been predated and taken away whole by a predator such as a Yellow-vented Bulbul cannot be ruled out. It is also noted that several different actions may happen to the nest after the chicks are fledged: re-used, dismantling of bits of nest for possible use elsewhere or left as it is. The various contributions by readers of their personal experiences are valuable and serves to add to our knowledge of a species of bird that may appear common to most of us but for which there are still gaps to be learned. So keep a lookout for future nesting of Olive-backed Sunbirds. You may well observe something new & intriguing! Thanks are due to Alan Owyong, Basanthi Seetoh, Chen Eddie, Clara Tan, Lim Khoon Hin, MeiLin Khoo, Ong PL, Puran Kaur, Tracy Heng, VirgoSG, Weijie Liao & 众生云云.