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.

Monday, August 5, 2013


I’m sure you’ve seen those documentaries about social insects where the camera snakes you down into the depths of the colony and there - lit by a ghostly green glow - you witness eerie fungal gardens, ants herding caterpillars and grotesque monarchs stuffing themselves on delicacies.

Well at the moment I feel as if I’ve somehow got trapped down there.

It all started a few days ago when I arrived home to find my living room abuzz.
As I opened the front door the sound hit me like a palpable wave; a droning, wrap-around buzz so intense I could almost see it.
There were bees everywhere. The air was thick with them. They were hovering and crawling and revving for takeoff. There were bees doing their waggle dance, pirouetting and tangoing within a circle of spectators; there were bees conferring quietly in small huddles and bees sitting calmly in apparent contemplation. The windows were coated, inside and out, with a mass of small bodies, but – and this worried me the most - they weren’t angry bees, striving to get out. Disconcertingly, they all had a laidback, we-want-to-be-here kind of manner.
All my pets had retreated outside and were looking as dismayed as I felt.

Of the 20,000 known species of bee (argh!), only seven are honey bees (all in the genus Apis). This select group (whose colonies cache honey is waxy combs) is thought to have originated in SE Asia, and our much loved common honeybee (Apis mellifera) started life in tropical east Africa before buzzing on northward.
Photo posted on Flickr by Goshzilla-Dann.

What was going on?
Had a swarm settled in my house?
I prowled disconsolately through the bee-clouded rooms, searching vainly for the tell-tale ball of bees. Then I tried following one of the bustling trade routes, and the hovering, buzzing hordes led me slowly back to my mealworm colony (housed in large plastic basins on top of a cupboard in the lounge room). Peering into a basin I was appalled to find a seething mass of bees, all rolling and writhing in apparent ecstasy, among the mealworms.
What the...??
Had I stumbled upon some dreadful orgy; a bizarre bacchanalia of miscegenation? 
Then I noticed that the writhing bees looked as if they were wearing cargo-pants whose bulging pockets were stuffed with something white.
Ah ha!  (A light bulb moment.)
They were gathering flour!

Err... flour??

Bees sifting flour from my mealworms’ bran.

Tentatively edging my way through the miasma of bees in the kitchen, I discovered another orgiastic clump squirming about in an open pack of maize meal.
Why had I never heard of bees behaving like this?
I mean, sure, bees show an unhealthy interest in sweet beverages. But dry goods? And it’s not as if I’m a complete neophyte when it comes to bees. As a child I shared home and hearth with a feral swarm (which resided in the chimney). Bee-stings were a routine hazard of television viewing, but never once did the little beasts attempt to pilfer our baking supplies.

With a reckless disregard for personal safety, I grabbed up the flour-bearing items and rushed them out to the veranda. A stream of bees accompanied me, and I prayed that the thousands still humming about inside the house would follow the food.

Could it be that they were starving? It’s been a bad year for bugs (as my skinny mongooses can attest); maybe the colony has scoffed its winter honey stores and is simply desperate? 
But then I looked at the exuberance of daisies currently blooming in my garden.
Nary a bee.

My scorned Namaqua daisies.

Evidence that other pollinators find my daisies attractive.

Craftily I moved the mealworm basins in amongst the flowers, hoping the bees might get the hint.
They didn’t.
But at least they all drifted out of the house, gathering in a massive, swirling column above the victuals. I discovered that if I laid out a smorgasbord of titbits (sugar water, maize meal and an open packet of cake flour), they deserted my traumatised mealworms and I was able to sneak the containers back indoors.
To what extent my mealworms have been scarred by this ghastly experience, I do not know. Caterpillars go off their food when bees buzz overhead (nibbling only one-third as much as usual). But the species used in this experiment (beet armyworms) sport special sensory hairs that respond to the vibration of buzzing wings (to track incoming parasitic wasps). As far as I know, my mealworms are hairless, so maybe they’ll make a full recovery.

Of course the bees are behaving most amicably and I remain unstung. However, the psychological impact on my dogs may be a problem. It was while I was fishing drowning bees out of a 0.5 mm smear of sugar water, that I noticed Wizard staring at me with a look of astonished disbelief. He’d come dashing over to interpose himself between me and whoever I was talking to (as alpha male he feels he has the right of veto), only to discover I was conversing with bees. Since then his attitude to our insect plague has changed: whenever a bee buzzes him, or lands in his bowl, or entangles in his fur, he fixes me with a look of profound reproach.

‘Hey look: it's a squashed bee!’
My dogs aren’t alone in disliking bees. When researchers played bee recordings to herds of snoozing elephants, the pachyderms immediately fled the scene, retreating about 60 m (200 ft) with their tails in the air. This little guy, however, hasn’t fallen victim to a bee (or car); he’s just annoying Mum by playing on the road.

Now it’s no surprise that bees are well-equipped to garner pollen (and flour?) but they’ve got one adaptation that’s genuinely electrifying. When bees zip around in their busy buzzing way, their bodies are bombarded by dust motes and other little bits of air-borne grunge. These minor collisions scrape electrons off the bee’s outer waxy cuticle and, voila, you get a positively charged bee. Flowers - in contrast to bees - sport a negative electrical field (at least on sunny days) and we all know how opposites attract. So when a positive little bee comes hovering down, the flower’s pollen flies up to the bee, like iron filings to a magnet.

But the niftiness doesn’t stop there.
Bees can also discern the electrical fields of flowers. When a conscientious worker bee touches down on a bloom, she neutralises its negative charge, and it takes a couple of minutes for the flower’s negativity to restore itself (rather like when I eat a piece of chocolate). This means that bees zooming about above a field of flowers can spot which ones have just been plundered and save themselves a fruitless nectarless visit.

It’s the bees’ flagella (the very tips of their antennae) that sense electrical fields. Pushed or pulled by an electrical charge, the flagellum’s tiny movements are monitored by touch-sensitive fibres within the bee’s antenna joints. When researchers unkindly immobilised these joints (by covering them with wax), the bees could no longer tell positive from negative.
Photo posted on Flickr by Johan J. Ingles-Le Nobel.

I have decided that today is D-day. I’m withdrawing all aid. I’ve carefully hidden my mealworm containers away inside my wardrobe (hey, who needs clothes?) and have locked up all cereal products.
Fingers crossed that the bees will leave!

Sweet-toothed, mead-guzzling humans have kept Apis mellifera for at least 3000 years. Archaeologists uncovered 30 hives (made of straw and unbaked clay) dating from about 900 BC at a dig in Israel’s Jordan Valley. However, it wasn’t until the 18-19th century that people learnt how to pinch the honey without killing the golden goose colony. Photo by Gwendolyn Stansbury.

The local little bee-eater family (Merops pusilla): possible justification for indoor foraging?
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