Monday, August 26, 2013

Archaeopteryx meets Priscilla

Ask people to name an iconic African bird and you’ll likely wind up with a whole lake-rim of flamingos and ostriches, plus maybe a ground hornbill or guineafowl thrown in for luck (ahhhhh... splosh).

But of all the myriad feathered critters cluttering the airspace of this continent, there are only two orders who flutter here and nowhere else: the mousebirds and the turacos.

I’ve already sung the praises of cute little mousebirds, so today I’ll take you down to the river to meet one of the weirdest birds I know.
A creature of the forest, around here it lives only in the verdant tangle of trees along the riverbank.  As you pass beneath the towering leadwoods, jackal berries and figs, you’ll hear its eerie kok-kok-kok-kok-kok call (which rises, in strength and pitch, to a deafening crescendo) reverberate through the gloom (you can also experience it here).
Carefully scan the smooth upper branches of that giant fig... but no...
Wait... there!
In that water berry, there’s movement.
A large ungainly bird suddenly lopes out along a branch, swaying slightly from side to side as it runs towards you. At first it looks to be black, its long wedge-shaped tail dark against the sky, but as it paces through a splash of sunlight you see its flamboyant plumage: iridescent purples and greens with a flush of rose rising on its breast. Without pausing stride, it leaps over a gap and halts abruptly on a branch directly above you. For a moment it shifts uncertainly from foot to foot, craning first left, then right, trying to catch sight of you. Then, cocking its head on one side, it peers down with one carmine-encircled eye, raising its raffish violet crest (a movement suggestive of arching an eyebrow) and fixes you with a fierce quizzical glower.

This is the purple-crested turaco.

If it decides you’re scary enough, you’re in for a real treat.
After a moment of dithering, running and hopping, it opens its stubby, rounded wings to unfurl a dazzling pageant of scarlet. It then launches into an elegant, balletic leap and glides away to a nearby tree. (I couldn’t find an ‘available-for-use’ image of the bird in flight - and of course snapping one is way beyond me - but please take a look at this one; it’s worth it.)


Running through the treetops, the purple-crested turaco (Gallirex porphyreolopha) bears a distressing resemblance to the world’s earliest feathered aviators.

Young turacos (this one’s an up-and-coming Ross’s turaco) even bear gnarly claws on their wing joints (used for pre-flight travel). They sensibly lose these primordial mementos in the embarrassment of adolescence. Photo posted on Flickr by SeaworldSA.
 
The turacos’ proficiency at tree-clambering is aided and abetted by a weird, reversible outer toe. This accessory normally sits at right angles to the axis of the foot, but can be swivelled fore or aft, depending on need. Photo by Vince Smith.
 
Turacos are members of an ancient order (Musophagiformes) and - since they keep themselves to themselves - no one really knows who their relatives are. The proteins in their eye-lenses (hey, the first place you’d look, really) hint at kinship with songbirds, their feather parasites are cousins to those on itchy fowls and their strange, swivel toes place cuckoos in their ancestry.
But as far as I’m concerned, they’re like no other. There’s something absurd and incongruous about their awkward, cumbersome shape coupled with such over-the-top plumage. They somehow remind me of avian drag queens, and I’m always half expecting them to break into an Abba dance routine.
Of course, it’s entirely inappropriate to question the purple-cresteds’ sexual predilections: they’re highly conventional birds. Living in old-school nuclear families, they’re unflinchingly monogamous and defend their home turf (very noisily) from anyone who may disrupt their conservative familial bliss.


I included these dreadful images (typical of my photographic prowess) because they show (in a blurry way) courtship feeding. It sounds so romantic, doesn’t it? Then you realise he’s hacking up regurgitated fruit pulp...
 
Nevertheless she seems grateful. Maybe it’s because she knows there’s worse to come. Parent turacos not only chomp their little darlings’ old eggshells, they gulp down their excrement too.

Now if turacos are the closet transvestites of the avian world, it’s the way they come up with their extravagant costumes that’s earned them global notoriety. You see turacos are the only feathered critters able to wear green. Lesser birds may look green but it’s all a con. While others achieve their verdant hues using yellow feathers (structured to refract sunlight and reflect blue wave lengths), turacos manufacture a genuine green pigment, turacoverd. This unique colorant is a copper uroporphyrin compound made up of 6% copper. The birds’ brilliant red wing feathers (found in most of the forest-dwelling species) are also designer-made, tinted with another exclusive copper-based stain, turacin. (The rest of the world’s birds must make do with carotenoids, for bright, orangey reds, and phaeomelanins, for rusty reds). But accumulating so much copper is challenging (so that’s who’s stealing the telephone cables...) and it takes young turacos twelve months to grow as gaudy as their parents (cable theft is slow work?). It’s even been suggested that turacos are only able to employ copper-based pigments because they dwell in one of the world’s richest copper belts.

 
The local copper Mecca: humans have been mining the stuff around here for more than 1200 years. This is the Phalaborwa copper mine, about 60 km (37 miles) up the road.
 Photo by Roman Betik.


Pride of the kingdom. The purple-crested turaco (Gallirex porphyreolopha) is Swaziland’s national bird. But fame and fortune come at a cost: the species’ dazzling flight feathers feature prominently in the ceremonial regalia of the Swazi and Zulu royal families.
Photo by Lip Kee.
 
Of course turacos are not alone in using copper to brighten up their world. Humans have been daubing this metal about ever since those old winos, the ancient Greeks, discovered how to cook up verdigris (expose copper plates to the fumes of fermenting grapes, then scrape off the crust of blue-green tarnish). Unfortunately humankind subsequently went astray (oh, that’s unusual) creating killer wallpaper throughout the 19thC using a copper-arsenic dye (Napoleon’s emerald walls probably hastened his demise: studies show his hair samples are chockfull of arsenic).
Sadly, this pigment was also used to tint clothing, sweets and deserts. A mass poisoning in Greennock, Scotland (where green confectionary was all the go during village celebrations) spawned a national aversion to green sweets (and I’ve indeed met a Sparkle-scoffing Scot who staunchly refused the green ones). Nevertheless, it’s all OK. Once our forebears figured out the perils of snacking on arsenic they converted their lovely green dye into an insecticide...


There are 23 species of turaco (all native to deepest, darkest Africa) and I couldn’t resist showing you how spiffy they are. This demur little one is a Knysna turaco (Tauraco corythax) from, well, Knysna in South Africa. Photo by Johann du Preez.
 

“What do you mean, you’ve never HEARD of turacos!”
Photo (of a white-cheeked turaco, Tauraco leucotis) by Loren Sztager.
 

Like all turacos, the red-crested (Tauraco erythrolophus) from Angola likes to munch fruit, flowers and buds. They’re such committed fruitarians that they even feed their chicks mostly just fruit pulp. Photo by Ciaran Dunston.
 
Turacos once laboured under the name of plantain-eaters until ornithologists realised they didn’t. This one’s a great blue turaco (Corythaeola cristata) at home in the Congo jungle.
Photo by Brent Moore.


As well as the brightly coloured forest species, there are a few drab turacos who knock about in open woodland (the unfortunately named go-away-birds). But what these species lack in garishness they make up for in behavioural peculiarities. The grey go-away-bird (Corythaixoides concolor), who lives around here, often breeds in cooperative groups.
Photo by Arno Meintjes.

 
Livingston’s turaco, I presume (Tauraco livingstoni). This species explores the forests of southern Tanzania and Malawi. Photo by Heather Paul.
 

Ross’s turaco (Musophaga rossae) ready for the mardi gras. Longevity is one of the turaco's many claims to fame with captive ones surviving more than 30 years.
Photo posted on Flickr by San Diego shooter.
 

 
The Hartlaub’s turaco (Tauraco hartlaubi) leaps about in the forests of the Kenyan highlands.
Photo by Francesco Veronesi.
 
“Mama mia, here we go again... my, my... how can I resist you?” 
Photo posted on Flickr by Belgianchocolate.
 

10 comments:

  1. Another wonderful post. I did not know that young turacos had claws on their wing joints. The same with a New World bird that looks even more dinosaur-like, the Hoatzin. There are many similarities between these birds.

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    1. Sorry for my absurdly slow reply! You're not alone in noticing the similarities between hoatzins and turacos; they used to be considered relatives. However recent work suggests that they aren't actually birds of a feather...

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  2. I remember learning about turacos in my college ornithology class when we talked about feather pigments. I've been fascinated by them ever since.

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  3. Fascinating variations in color!

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    1. It reminds me of the Aboriginal dreamtime story that describes how birds were created from the falling shards after a rainbow shattered.

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  4. ....so if Gallirex porphyreolopha were to be introduced to another area they could lose their lovely colours? Such nice birdies. I have a Eucomis called 'Swazi Pride' that has yet to flower so I hope there's a connection. Most informative. Thank you! Napoleon was probably murdered btw, unless he really liked licking his wallpaper. We just don't know.

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    1. I know lots of captive birds are more drab than their wild counterparts because their artificial diet lacks the stuff they need to make bright pigments (scarlet ibis and flamingos spring to mind) but I'm not sure if this also applies to turacos.

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  5. ak! Gah! Those colors have fried my brain.

    Can't talk, swooning....

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    1. I'd better write a post on sunbirds (Africa's attempt at hummingbirds). The mind-blowing impact of their plumage should alleviate your neural overheating.

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