Hybridisation in the wild between the great hornbill (Buceros bicornis) and the rhinoceros hornbill (Buceros rhinoceros) in Thailand and its genetic assessment

Abstract

The great hornbill (Buceros bicornis) and the rhinoceros hornbill (B. rhinoceros) are among the largest Asian hornbill species and they overlap in parts of their ranges. These two species resemble each other in appearance and breeding habits and are sister taxa. In 2004 and 2008, two occurrences of mating in the wild between a male rhinoceros hornbill and a female great hornbill were discovered in the forests of Budo Mountain, southern Thailand. These mated pairs each successfully raised a chick. Morphological and phenotypic characteristics of the chicks most resemble the great hornbill with a few distinctive features shared between both hornbills. Genetic data confirmed these incidences of hybridisation. Analysis of mitochondrial DNA in the hypervariable control region III of these two chicks showed similar patterns to those of their mother, the great hornbill. An investigation of parentage, using 11 microsatellite loci developed from the great hornbill, indicated that the chicks shared at least one allele with the putative mother at all loci. Three different alleles, specific for rhinoceros hornbill, were also detected in the chicks. This suggests that the female great hornbill and male rhinoceros hornbill were the true parents of these hybrid chicks, and that the chicks shared the same mother. Our results is the first report of hybridisation between the great hornbill and the rhinoceros hornbill in the wild, and has been genetically confirmed. © National University of Singapore.