Great and Rhinoceros Hornbills: More images

The courtship behaviour of a Great (Buceros bicronis) and a Rhinoceros Hornbill (B. rhinoceros), both female, at Eng Neo has already been told. However, through the generosity of Meng and Melinda Chan, we are able to showcase here more of what actually happened around the old albizia tree (Paraserianthes falcataria). The pair would meet in the morning and/or evening and the Great (above right, taking on the role of a male) would always check on the cavity. "He" would then fly back to join the Rhinoceros on a nearby branch and delicately fed the latter with a fig. This is the standard courtship ritual. Possibly, this was to reassure her that "he" would keep on feeding her should she be sealed up in the cavity during egg incubation and after (should this happen). Only then would the Rhinoceros fly off to check the potential nest cavity. In the image below you can see a Greater Racket-tailed Drongo (Dicrurus paradisus) harassing the Rhinoceros. There was always a pair, probably breeding nearby, that followed the hornbills around.
The image on the left shows the Rhinoceros, with her head inside the cavity, checking the interior. The Great is perching on the tree trunk below, waiting for her decision.

The pair has been visiting the tree during February to May, as this is supposed to be the breeding period. There is a report of someone seeing the Rhinoceros entering the cavity, to move out soon after. But there has not been any attempt of the Rhinoceros sealing herself inside the cavity. This would be a distinct possibility, considering that both are females. And a female bird would only enter the cavity and seal herself in after copulation.

Such aberrant behaviour probably arises out of desperation. After all, there is only one of each bird in Singapore, both escapees. And they have come together out of loneliness.

Text by YC, images by Meng and Melinda Chan.