Loneliness makes strange bedfellows: Great and Rhinoceros Hornbills

A pair of hornbills comprising a Great (Buceros bicornis) and a Rhinoceros (B. rhinoceros), both females, have been visiting an old albizia tree (Paraserianthes falcataria) around the Eng Neo area from late February to April to check on a cavity as a possible nesting site.

Every morning and sometimes in the evening, the birds would fly to the tree and inspect the cavity. The Great Hornbill plays the role of a male, trying to lure the Rhinoceros to the cavity by placing food inside. It then flies to the nearby tree to join the Rhinoceros and sometimes feed the latter as part of their courtship ritual. Once in a while the Rhinoceros would respond to the Great’s urging and fly to the cavity to inspect it.
The Great has also been observed to peck hard on the periphery of the cavity in an effort to enlarge the opening.

After some time spent outside the cavity, both birds would fly around, to alight on the yellow flame (Peltophorum pterocarpum) and other trees around the area. There, the pair would stay close together for up to half an hour or so. The Great Hornbill, a probable escapee from Jurong Bird Park, has a metal tag on her right leg. The pair are obviously used to people as they appear tame.

This pair has been seen in Hindehede Quarry prospecting for a potential nesting cavity.

Ng Bee Choo has this to say: "A pair of Great Hornbills died in Sentosa island a number of years ago. This Great Hornbill must be very desperate. Morten Strange has seen it once in the Singapore Botanic Gardens, checking a nesting hole. Both hornbills belong to the genus Buceros. In Thailand, according to Dr Pilai Poonswad, these two hornbills mated and produced a hybrid. In the above case both birds are females. They have paired up for company… however, if they try to mate, this must be a case of lesbian birds. Must be recorded as a case study of birds in desperation."

Top image (Great left, Rhinoceros right) and bottom of Great inspecting cavity by YC.