TOUCAN-BARBETS Semnornithidae
One of most prized birds in South America is Toucan-Barbet (left). James Ownby took this gorgeous photo as the bird foraged in a fruiting tree in the western Andes of Ecuador. Toucan-Barbet, found only in the Andes of Colombia and Ecuador, is one of two species in the genus Semnornis; the other is Prong-billed Barbet of Central America. Both of aberrant Piciformes of uncertain affinities that have limited ranges in montane cloud forests, and together they are known as (small case) toucan-barbets.

Recent molecular evidence has proven that New World barbets, toucans, and these two birds in Semnornis (e.g., the toucan-barbets) are more closely related to each other than they are to Old World barbets (Burton 1984, Prum 1988, Sibley and Ahlquist 1990, Lanyon & Hall 1994, Barker & Lanyon 2000, Johansson et al. 2001, Johansson & Ericson 2003, Moyle 2004). These studies have differed as to whether Semnornis is more closely related to New World barbets or to toucans. The most recent and comprehensive analysis (Moyle 2004) could not place them with certainty, but they seem to be a separate group that evolved early in the New World radiation. Given the evidence that toucans are actually 'big-billed New World barbets' when compared to barbets in the Old World, there are several different taxonomic approaches. 

The Handbook of the Birds of the World (Short & Horne 2002) sticks with the traditional approach of two families: all the barbets (including these Toucan-Barbets) in a barbet family and the toucans in a toucan family. They argue that it is easy to tell whether any bird in the group is a barbet or a toucan, and that the barbets are ecological counterparts on each of the three major tropical continents. This is true enough, but it is a bit like sticking your head in the ground to avoid the new evidence of relationships. I prefer a more modern approach, discussed below.

My poor backlit photo is how one more typically sees the Toucan-Barbet, high in the canopy of a Cecropia canopy, where one glimpse just a touch of the brilliant reds & yellows, offset by soft grays, that characterize its plumage. They love fruiting trees indeed, Remsen et al. (1993) found that 100% of the stomach contents of both toucan-barbets was fruit. 

Old Word barbets are here treated as two separate families, Asian Barbets [Megalaimidae] and African Barbets [Lybiidae]. Recent genetic data (Moyle 2004) support the monophyly of the barbet radiations within each region. To emphasize the close relationships among New World taxa, the three groups New World barbets, toucan-barbets, and toucans were treated as subfamilies of a single family, Ramphastidae, by AOU (1998). This approach means that the Toucans are lost as family and they become just "big-billed barbets." I know that from the perspective of world birder, Toucans are a distinctive group, easily recognized as Toucans and nothing else, and that they are exciting birds to see. I like the idea of Toucans as their own family.

The only logical way to accommodate this desire, and still be consistent with evolutionary relationships as we now know them, is to treat all three New World groups. This is perfectly consistent in ornithology and is the approach now taken by the South American Checklist Committee. They state that: "Semnornis is treated as separate family until affinities resolved," noting that an "analysis of characters of the hindlimb musculature supported the traditional inclusion of Semnornis in the barbets, but Prum's (1988) analysis of morphological data indicated that Semnornis is the sister taxon to the Ramphastidae, not the Capitonidae. Genetic data indicate that Semnornis may be basal to both families (Barker and Lanyon 2000)."

Toucan-barbets do appear transitional between barbets and toucans. In their 100% fruit-eating behavior they are more similar to toucans than to New World Barbets. Both toucan-barbets are also unique among all barbet relatives in having the bill tip extending forward and fitting into a notch in the tip below. Young birds use these scissor-like tips to easily "bite" their way out of nesting cavities (Short & Horne 2001). This holds true for Prong-billed Barbet in the mountains of Costa Rica and western Panama. It is not nearly as colorful as Toucan-Barbet but it does have the unique bill, as shown in this nice shot (below) by Marc Fenner:
In summary: to accurate represent the relationships of what used to the Barbets and the Toucans, we now have five separate lineages and five separate families, including the Toucan-Barbets [Semnornithidae]. I'm happy with that arrangements. They are a special, unique, and highly sought group. Use the links below to see the other other four families:

Photos: Both photos of Toucan Barbet Semnornis ramphastrinus were taken along the Nono-Mindo Rd., Ecuador. James Ownby photographed his on 8 Apr 2002 at Septimo Paraiso Resort; my distant shot was higher on the ridge and farther south along the road on 17 Apr 1992. Marc Fenner photographed Prong-billed Barbet S. frantzii at Monteverde, Costa Rica, in March 1991. Photos are © 2004 James Ownby and Don Roberson and Marc Fenner, respectively; used with permission, all rights reserved.

More evocative shots from James Ownby's South Americas trip are on his web site [see his Ecuador travel diary].  Marc Fenner hosts a fine web site on birding Costa Rica.

Family Book

Short, L.L., and J.F.M. Horne. 2001. Toucans, Barbets, and Honeyguides. Oxford Univ. Press, Oxford.

I must confess that I don't actually own this book, nor have I done more that quickly glance through it in a bookstore. But every one of the Oxford Univ. Press series on bird families has been excellent, and this looks equally solid. I presume that the "meat" of this book has been summarized by the same authors in their Handbook of the Birds of the World series (Short & Horne 2002) which I do own and have studied.
     Consistent with Oxford books in this series, the introductory material is extensive and the species accounts thorough. Plates and illustrations more than adequately enhance the text. If I have any quibble, it is with the conservative approach to family level taxonomy but, then again, this was written before the molecular studies by Johansson et al. (2001) and Moyle (2004).
Literature cited:
American Ornithologists' Union. 1998. Check-List of North American Birds. 7th ed. A.O.U., Washington, D.C.

Barker, F.K., and S.M. Lanyon. 2000. The impact of parsimony weighting schemes on inferred relationships among toucans and Neotropical barbets (Aves: Piciformes). Molecular Phylogenetics and Evolution 15: 215-234.

Burton, P.J.K. 1984. Anatomy and evolution of the feeding apparatus in the avian orders Coraciiformes and Piciformes. Bull. Brit. Mus. (Natural History) 47: 331-441.

Dickinson, E.C., ed. 2003. The Howard & Moore Complete Checklist of the Birds of the World. 3d ed. Princeton Univ. Press, Princeton, N.J.

Johansson, U.S., and P. G.P. Ericson. 2003. Molecular support for a sister group relationship between Pici and Glabulae (Piciformes sensu Wetmore 1960). J. Avian Biology 34: 185-197.

Johansson, U.S., T.J. Parsons, M. Irestedt, and P.G.P. Ericson. 2001. Clades within "higher land birds," evaluated by nuclear DNA sequences. J. Zool. Syst. Evol. Research 39: 37-51

Lanyon, S.M., and J.G. Hall. 1994. Re-examination of barbet monophyly using mitochondrial-DNA sequence data. Auk 111: 389-397.

Moyle, R.G. 2004. Phylogenetics of barbets (Aves: Piciformes) based on nuclear and mitochondrial DNA sequence data. Molecular Phylogenetics & Evolution 30: 187-200.

Prum, R.O. 1988. Phylogenetic interrelationships of the barbets (Aves: Capitonidae) and toucans (Aves: Ramphastidae) based on morphology with comparisons to DNA-DNA hybridization. Zool. J. Linnaean Soc. 92: 313-343.

Remsen, J.V., Jr., M.A. Hyde, and A. Chapman. 1993. The diets of neotropical trogons, motmots, barbets and toucans. Condor 95: 178-192.

Short, L.L., and J.F.M. Horne. 2002. Family Capitonidae (Barbets), pp. 140-219 in Del Hoyo, J. Elliott, A., & Sargatal, J. eds. Handbook of the Birds of the World. Lynx Edicions, Barcelona.

Sibley, C.G., and J.E. Ahlquist. 1990. Phylogeny and Classification of Birds of the World. Yale Univ. Press, New Haven, CT.



Page created 25 Aug-6 Sep 2004, revised 26 Sep 2004