Rigor Vitae: Life Unyielding

Monday, June 19, 2006


I sat on the edge of my seat, wedged uncomfortably between two men and the front passenger seat. Seven of us, including the driver, burdened the little Toyota as it sprayed rufous mud into the verdant forest around us. The car fishtailed, then came to a stop, mired to the hubcaps. The doors opened, and we all exited, happy for the chance to stretch our limbs. This was my initiation to the Central African ritual of pushing a stuck bush taxi out of the mud. Over the next three months I would get to know it well. I had landed at the Douala airport the previous evening, and was making my way toward the little Cameroonian town of Mundemba, gateway to the Korup forest. As the taxi door slammed, a pair of startling crimson wings carried their owner from a roadside Musanga tree into the depths of the jungle. It was my first day in Central Africa, but I recognized the bird immediately as a turaco, a member of an ancient group that has remained little-changed for at least 30 million years.

The typical turaco looks superficially like many of the cuckoo relatives, particularly the Madagascan couas, and for many years they were lumped into the order Cuculiformes, along with the coucals, anis, and the bizarre South American Hoatzin (Opisthocomus hoatzin). DNA analyses have shown them to be quite unrelated, though, and today they are given their own order, Musophagiformes. Turacos' closest living relatives are probably the owls and nightjars, but no other living bird could be rightly called a cousin. Their athletic behavior is their most conspicuous distinction from the Cuculiformes, which, except for the roadrunners of the family Neomorphidae, range from mildly to extremely clumsy. The forest turacos are particularly adept at running and leaping through the branches, often traveling at bullet speed through the jungle without spreading their wings. A number of physical features distinguish them, among which are the lack of a vomer (an internal facial bone) and furcula (wishbone), and an oddly-built foot, whose outer toe juts out almost perpendicular from the rest.

Oligocene turaco fossils have been found as far north as Germany, but today a single family, Musophagidae, is restricted to sub-Saharan Africa. The typical turacos of the subfamily Musophaginae are immediately distinguishable by those deep red wings that caught my eye in the Cameroon bird. This pigment, also present in the crests of many species, is unique to the subfamily, all of whose members produce the copper compound called turacin. It is often stated that this pigment is water soluble, and that bathing turacos will stain their water pink, but I have never been able to reproduce this, even by boiling feathers. I have a number of shed turaco primaries that are well over fifteen years old, and still a deep red. Another unique copper-based pigment is turacoverdin, which is the only green pigment found in birds. The green seen in parrots, trogons, hummingbirds and others is a result of structural irridescence, and not true pigment.

The bird frightened by our bush taxi was one of 10 to 20 or more species in the genus Tauraco, all of which are green, crested, and extremely hard to identify in the field. It was probably a Yellow-billed Turaco (T. macrorhynchus), which is more typical of the thick jungle habitat where it was spotted. However, it might have been a Green Turaco (T. persa), a species that encompasses a complex of birds found from South Africa to Guinea, and should probably be split into half a dozen or so species. A close relative, Bannerman's Turaco (T. bannermani) is restricted to the Bamboutos Mountains in the Bamenda Highlands of western Cameroon. This is one of the most critically endangered African birds, and although I found it common on the top of Mount Oku, ten years ago, forest degradation, even in this rugged country, is happening at a rate that will probably result in the bird's extinction within the next twenty years. The other genus of typical turacos, Musophaga, contains five similar, but less green birds (see the Lady Ross' Plantain-eaters above). The term “plantain-eater” is shared with the genus of gray birds, Crinifer, and is but one confusing term for the Musophaga spp. In southern Africa, they're known as “louries,” a general Afrikaans term for all turacos.

The second turaco subfamily, Criniferinae, contains three genera of gray birds that are common in the drier, open regions of the continent: Crinifer contains the two species of gray plantain-eater, while Corythaixoides and the monotypic genus Criniferoides contain the three species called go-away birds. All five birds are conspicuous savannah birds with the prominent crests and long tails shared by all Musophagiformes. Like the entire order, these omnivores feed on a wide variety of fruits, leaves, buds and invertebrates.

The most unusual turaco is the largest, and the one most commonly seen in the thick Central African rainforests. The Great Blue Turaco (Corythaeola cristata) is a spectacular bird. The size of a leghorn chicken and deep cerulean blue, with a yellow belly, its head bears a thick black crest that looks like a shaving brush. The most social of all the turacos, it is rarely seen alone—more often in noisy groups of about a half dozen. Nesting occurs the year round, and breeding behavior is typical of the whole order. Two eggs are laid in a well-hidden, shallow stick nest that looks much like a fruit-pigeon nest. Incubation is done by both parent birds, and lasts about 30 days. Immediately upon hatching, the chicks are active, and their eyes are open. Both parents regurgitate to feed the chicks, which, like many tropical birds, grow very slowly, remaining in the nest for a couple of months, although much of the latter month is spent exploring the outer branches of the next tree. The feathers are not completely grown until the birds are nearly three months old. In a number of turaco species, it appears normal for just one chick to survive to fledging. Whether or not this is due to siblicide is unknown.
upper: LADY ROSS' PLANTAIN-EATERS (1999) acrylic 15" x 36"


Anonymous Anonymous said...

Thanks for the great information Carel. Very interesting birds...that I've seen only in other artist's work and a few less than wonderful photographs.

5:34 PM  
Blogger Carel Brest van Kempen said...

I had the good fortune to work with three different species in zoos before i ever saw a turaco in the wild. Like so many animals, you really have to see these things move to have really seen them.

4:54 PM  
Anonymous Anonymous said...

Another informative piece and wonderful art as always! (-:

1:31 PM  

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