“Two Grey-rumped Treeswift (Hemiprocne longipennis) nests were discovered at Singapore’s Bishan Park on 8th May 2014 at around 9:00 am. The locations of the nests are shown in the map above.
“I was at car park B when I noticed a Grey-rumped Treeswift flying around (above).
“While photographing birds-in-flight, I saw a treeswift landing in a tree next to car park, with another waiting on a nearby branch. On closer look I realised that they were nesting (above, below). No egg was observed in the nest. An interesting observation – this pair of treeswifts was rehearsing “changing shift” movements multiple times. One flew out, circled around and returned to the nest. It rested for awhile, then flew off again. I was not sure whether they were the same bird.
“After photographing the first nest, I moved to car park C. Again, I observed a similar pattern in another pair of treeswifts. This was second nest (below).
“The next evening Jeremiah Loh, 藤本 の水眀 and myself noticed there were at least 4-5 male teeswifts flying around this nesting square at Bishan Park.
“These treeswifts were resting on another tree, not the nesting tree (above). Three of the males are shown below.
“On the same day a bird was seen in the second nest. However this was the last time I saw it (below).
“Only on 22nd May was it confirmed that the nesting failed as no treeswift was seen at any time in the nest (below).
“On 12th May at 10:45 am, the adults in the first nest were changing shift.
“The above-left shows the female at the nest. Above-right shows the male coming to take over incubation duties.
“It was on 16th May that I finally saw the egg in the nest (below-left).
“Another shift change was documented on 17th at 08:00 pm. This time the male gave way to the female who in turn gave way to another male. The video clip showing this move by Wong Weng Fai can be viewed HERE – the first ever evidence of cooperative breeding.
“The next evening (18th May at 08:00 pm), only the female was in the nest (above-right).
On 22nd May at 9.45 am, another shift change occurred. This time the male gave way to the female – see video clip HERE.
“A change in strategy was observed on 26th May at 9.00am when a male flew in and perched on the branch above the nest. It then flew down and relieve the female incubating the egg. Usually the male flew directly to the nest. The female then flew to the non-nesting tree to join another male there.
“The next day when the male was in the nest, there were another male and a female at the non-nesting tree (above). This was the second time when a pair was seen in this tree while a male was incubating the egg in the nest at the nesting tree. This situation is similar to the time when Weng Fai recorded his video showing cooperative breeding.
“Subsequent morning shift changes involved both sexes (above) except on 5th June when two males were involved (below).”
Ling Kwee Chang
4. 22 May 2014First report of Cooperative Breeding in Grey-rumped Treeswift
This post is a cooperative effort between Birds, Insects N Creatures Of Asia and BESG to bring the study of birds and their behavior through photography and videography to a wider audience.