VogelPark - Walsrode Birdpark Hunting for Red-billed Hornbills

In his publication from 2002 Dr. Allan Kemp considers the possibility that at least three of the five or perhaps even six known subspecies of the Red-billed Hornbill (Tockus erythrorhynchus) might better be considered to be independent species (KEMP, 2002). The Walsrode Birdpark has picked up on the discussions on the complicated taxonomy of this species and has initiated a small study on the species status in captivity.

Three of the Taxa in question are very new to science. The subspecies Tockus erythrorhynchus kempi from West-Africa was not described until 2000 and Tockus erythrorhynchus ruahae from East-Africa not till two years later. A third form from North-Eastern Africa still remains to be formally described. It has been suggested that these three „new“ subspecies of the Red-billed Hornbill (Tockus erythrorhynchus) are indeed distinctive enough from the 3 other forms, to be considered as a new species (Tockus kempi). Also the subspecies Tockus erythrorhynchus rufirostris and Tockus erythrorhynchus damarensis may warrant status as “good” species.

Currently studies into the genetics, distribution, ecology, behaviour and calls of the different forms are ongoing and will hopefully help to clarify our picture of their relationships. Although much of the needed data is still incomplete it does appear that there is some overlapping of the distribution of the different forms in East-Africa where the distribution areas of Tockus kempi ruahae and Tockus erythrorhynchus erythrorhynchus meet in Tanzania.

In Southern Africa the distribution areas of Tockus (erythrorhynchus) rufirostris and Tockus (erythrorhynchus) damarensis also meet. Here the dynamics of the two forms hybrid-zones are better understood and studies confirm that hybrid offspring have considerably poorer survival chances in the wild than that of pure offspring from either form (DELPORT, 2004). This certainly suggests that the subspecies are not as closely related as it has been assumed in the past. However until genetic studies confirm these findings and genetic material have been collected from all the different forms much of our knowledge remain speculative.

The decades of captive management of Red-billed Hornbills in zoo’s and with private breeders have until now not contributed with much data although importations of live wild-caught Red-billed Hornbills from East Africa often included both subspecies occurring there. In the absence of insight the differences in the birds would frequently be interpreted as sexual dimorphism by dealers leaving numerous mixed pairs in zoos and private holding through out Europe.
For a long-term sustainable population of Red-billed Hornbills in captivity it is essential that these different forms are not interbred as regular crossbreeding could, in the absence of new imports, easily lead to a collapse of the maintained populations. If they already have been interbred this could provide valuable information on the relationships between these forms.

The VogelPark in Walsrode and the Hornbill Taxon Advisory Group (TAG) of the European Association of Zoo’s and Aquaria (EAZA) are very interested in determining the status of the remaining captive populations.
This is why the VogelPark has initiated a study that aim to identify which of the different forms are kept and to estimate in which numbers they are present in collections.
A questionnaire that has been distributed to numerous zoos throughout Europe and North America with illustrations by the VogelPark artist Thomas Eichler is supposed to help the different zoos and holders to identify their birds. Until now we have not been able to confirm that a successful hybrid breeding of the different forms has ever occurred in captivity although many mixed pairs has been identified.
This remains one of the most important questions and the VogelPark would be very interested to hear about any such breeding results.

If spotted, please send an email to:  simon.jensen@vogelpark-walsrode.de