As early as November 2006 Angie Ng reported a pair of Oriental Pied Hornbills (Anthracoceros albirostris) checking out a cavity in an old, 22 m high damar hitam gajah (Shorea gibbosa) tree in Changi (left). This cavity probably resulted from faulty pruning of a side branch many years ago. The cut surface was healing but apparently not fast enough. The exposed wood rotted, resulting in this cavity high up on the side of the main trunk, about 3 m from the top.
On the evening of 7th February, Meng and Melinda Chan saw the male bird trying unsuccessfully to entice the female to the cavity by placing some food inside. When the female refused to fly over, the male retrieved the food and flew off to join his mate.
KC Tsang was over at Changi the following day when he saw the female trying to enter the cavity with difficulty. She was enlarging the cavity, doing most of the work (below left). But the male, who was bigger, did also contribute to the labour (below right). Most of the time he was flying off, collecting lumps of mud and bringing them back for the female who was beginning to seal herself up, a little inside the circular opening of the cavity.
This continued for the next two day. The male was still very active bringing mud to the female, sometimes swallowing the mud and then regurgitating it to the female. The female can sometimes be very fussy and rejected the mud by throwing it out of the nest. The mud that was regurgitated by the male seemed to be a bit on the wet side, maybe that was how he made the mud pieces softer. The mud was collected from the near by field (above).
Throughout this period the male was flying to and fro bringing food and lumps of mud for the female (left top). His arrival varied from once every 10-15 minutes to 20 minutes. All this time the female continued enlarging the cavity and at the same time continued sealing herself in. She was observed throwing out pieces of debris. And the male continued to bring materials for her to seal herself in.
Finally, the female was sealed in (left bottom).
Images by Chan Yoke Meng, KC Tsang, Chan Yoke Meng, Allan Teo and Chan Yoke Meng.