The turacos make up the bird family Musophagidae (literally "banana-eaters"), which includes plantain-eaters and go-away-birds. In southern Africa both turacos and go-away-birds are commonly known as louries. They are semi-zygodactylous - the fourth (outer) toe can be switched back and forth. The second and third toes, which always point forward, are conjoined in some species. Musophagids often have prominent crests and long tails; the turacos are noted for peculiar and unique pigments giving them their bright green and red feathers.
Traditionally, this group has been allied with the cuckoos in the order Cuculiformes, but the Sibley-Ahlquist taxonomy raises this group to a full order Musophagiformes. They have been proposed to link the Hoatzin to the other living birds but this was later disputed.
Musophagids are medium-sized arboreal birds endemic to sub-Saharan Africa, where they live in forests, woodland and savanna. Their flight is weak, but they run quickly through the tree canopy. They feed mostly on fruits and to a lesser extent on leaves, buds, and flowers, occasionally taking small insects, snails, and slugs. Contrary to what the names might suggest, they generally do not eat bananas or plantains and indeed wild-living musophagids do not seem to use Musa as food at all.
They are gregarious birds that do not migrate. Many species are noisy, with the go-away-birds being especially noted for their piercing alarm calls, which alert other fauna to the presence of predators or hunters; their common name refers to this. Musophagids build large stick nests in trees, and lay 2 or 3 eggs. The young are born with thick down and open, or nearly-open, eyes.
The turacos are for the most part medium sized birds (the exception being the large Great Blue Turaco) with long tails and short, rounded wings. They range in length from 40–75 cm (16–30 in). Their flight is weak, but they are strong climbers and are able to move nimbly on branches and through vegetation. They have a unique foot arrangement, where the fourth toe can be brought around to the back of the foot where it almost touches the first toe, or brought around so that it is near the second and third. In spite of this flexibility the toe is actually usually held at right angles to the axis of the foot.
The plumage of Go-away-birds and plantain-eaters is mainly grey and white. The turacos on the other hand are brightly coloured birds, usually blue, green or purple. The green colour in turacos comes from turacoverdin, the only true green pigment in birds known to date. Other "greens" in bird colors result from a yellow pigment such as some carotenoid, combined with the prismatic physical structure of the feather itself which scatters the light in a particular way and giving a blue colour. Turaco wings contain the red pigment turacin, unlike in other birds where red colour is due to carotenoids. Both pigments are derived from porphyrins and only known from the Musophagidae at present, but especially the little-researched turacoverdin might have relatives in other birds. The incidence of turacoverdin in relation to habitat is of interest to scientists, being present in forest species but absent in savanna and acacia living species.
Little is known about the longevity of wild turacos but in captivity they are proving to be exceptionally long-lived, easily living to 30 in captivity. A bird in the Cotswold Wildlife Park Collection originally from Nigel Hewston discussed at the ITS AGM in Spring 2012 (at the same venue) was approaching its 37th year.
Evolution and systematics
The fossil genus Veflintornis is known from the Middle Miocene of Grive-Saint-Alban (France). It was established as Apopempsis by Pierce Brodkorb in 1971, but this is preoccupied by Schenkling's 1903 use of the name for some beetles. "Apopempsis" africanus (Early Miocene of Kenya) might also belong there.
Further fossil material of putative musophagids was found in Egypt as well as in Late Oligocene deposits at Gaimersheim (Germany) and Middle Miocene deposits at Grive-Saint-Alban and Vieux-Collonges (both France). While it is not entirely certain that these fossils indeed are of turacos, it nonetheless appears as if the family evolved in the Oligocene of central Europe or perhaps northern Africa, and later on shifted its distribution southwards. The climate of those European regions during the late Paleogene was not too dissimilar to that of (sub)tropical Africa today; the Saharan desert was not yet present and the distance across the Mediterranean was not much more than what it is today. Thus such a move south may well have been a very slow and gradual shifting of a large and continuous range.
The Early Eocene Promusophaga was initially believed to be the oldest record of the turacos; it was eventually reconsidered a distant relative of the ostrich and is now in the ratite family Lithornithidae. Filholornis from the Late Eocene or Early Oligocene of France is occasionally considered a musophagid, but its relationships have always been disputed. It is not often considered a turaco anymore in more recent times and has been synonymised with the presumed gruiform Talantatos, though it is not certain whether this will become widely accepted.
The living species of Musophagidae, arranged in taxonomic sequence, are:
- Genus Tauraco - green turacos
- Guinea Turaco, Tauraco persa includes subspecies T. p. buffoni Buffons Turaco
- Livingstone's Turaco, Tauraco livingstonii includes subsp T c phoebus Transvaal Turaco
- Schalow's Turaco, Tauraco schalowi includes T s chalcolophus Long-crested Turaco
- Knysna Turaco, Tauraco corythaix
- Black-billed Turaco, Tauraco schuettii includes T. s. emini, Pasha Emin's Turaco.
- White-crested Turaco, Tauraco leucolophus
- Fischer's Turaco, Tauraco fischeri
- Yellow-billed Turaco, Tauraco macrorhynchus
- Bannerman's Turaco, Tauraco bannermani
- Red-crested Turaco, Tauraco erythrolophus
- Hartlaub's Turaco, Tauraco hartlaubi
- White-cheeked Turaco, Tauraco leucotis
- Ruspoli's Turaco, Tauraco ruspolii
- Purple-crested Turaco, Tauraco (Gallirex) porphyreolophus a subgenus that may also include Ruwenzori Turacos (below)
- Genus Ruwenzorornis
- Ruwenzori Turaco - Ruwenzornis johnstoni
- Genus Musophaga - blue turacos
- Genus Corythaixoides - go-away-birds
- Genus Crinifer - plantain-eaters
- Genus Corythaeola
- Great Blue Turaco, Corythaeola cristata
Relationship with humans
The brilliant crimson flight feathers of turacos have been treasured as status symbols to Royalty and Paramount Chiefs all over Africa. They are recorded as being used exclusively for the Swazi and Zulu Royal families.
- Hughes & Baker (1999)
- Sorenson et al. (2003)
- Marchant, S. (1991). In Forshaw, Joseph. Encyclopaedia of Animals: Birds. London: Merehurst Press. p. 125. ISBN 1-85391-186-0.
- Turner, Donald (1997), "Family Musophagidae (Turacos)", in del Hoyo, Josep; Elliott, Andrew; Sargatal, Jordi, Handbook of the Birds of the World. Volume 4, Sandgrouse to Cuckoos, Barcelona: Lynx Edicions, pp. 480–508, ISBN 84-87334-22-9
- Mlíkovský (2002)
- "TT 149", a proximal left and a distal right tibiotarsus of a bird similar in size to living Tauraco: Ballmann (1969)
- [ITS Magazine Autumn 2003 (20)] www.turacos.org
- Ballmann, Peter (1969): Les Oiseaux miocènes de la Grive-Saint-Alban (Isère) [The Miocene birds of Grive-Saint-Alban (Isère)]. Geobios 2: 157-204. [French with English abstract] doi:10.1016/S0016-6995(69)80005-7 (HTML abstract)
- International Turaco Society (Magazines 1993-2012) also website 2001 www.turacos.org
- Mlíkovský, Jirí (2002): Cenozoic Birds of the World, Part 1: Europe. Ninox Press, Prague. ISBN 80-901105-3-8 PDF fulltext
- Hughes, Janice M. & Baker, Allan J. (1999): Phylogenetic relationships of the enigmatic hoatzin (Opisthocomus hoazin) resolved using mitochondrial and nuclear gene sequences. Molecular Biology and Evolution 16(9): 1300-1307. PDF fulltext
- Sorenson, Michael D.; Oneal, Elen; García-Moreno, Jaime & Mindell, David P. (2003): More Taxa, More Characters: The Hoatzin Problem is Still Unresolved. Molecular Biology and Evolution 20(9): 1484-1499. doi:10.1093/molbev/msg157 PDF fulltext Supplementary Material