Tuesday, August 31, 2010

The heat is on

Spring is in the air (well, maybe it's the pollen from the knob thorns), and the mongooses are abuzz with romance.

Achren - the alpha female in Ecthelion - is in oestrus.

How do I know? From the panic in the alpha male's eyes.

You think I'm kidding? I'm not. You see, dwarf mongooses are not fair and equitable when it comes to love. Only the group's upper echelons have a chance of scoring, and the alpha pair monopolises most of the action. Old Merriman (Ecthelion's battle-scarred alpha) will sire around 80% of all baby Ecthelions. But it's not an easy job.

During the 3-4 days that Achren is in heat, Merriman will guard her constantly. He trots along, just inches from her side, obsessively scanning the group for rivals while she calmly forages. If any male dares to venture within a couple of feet, Merriman lunges viciously, sending the intruder fleeing amid a chorus of submissive squeaking. Of course supremacy comes at a price. Each time Merriman tries to dig up a bug, Achren (named after a beautiful but wicked enchantress in Lloyd Alexander's Prydain series) casually strolls on. Merriman's torment is obvious as he momentarily vacillates between pursuing the juicy larvae and escorting his true love. Love wins every time.

Merriman (named after the Old One, Great Uncle Merry, in Susan Cooper's 'The Dark is Rising' series) enjoying the fruits of his diligence.

But despite Merriman's best efforts, every ten minutes or so, he loses sight of Achren entirely. I feel like shouting "Don't panic", but it's to no avail. Merriman races about the group frantically, peering over and around group members, searching behind bushes and rocks, and calling with rising hysteria. Achren completely ignores this show of ardour and continues to forage unperturbed. Although it seems absurd, Merriman's panic is not without cause: he's not the only one tracking Achren's movement. The moment she's unattended, Merlin (the deputy alpha) comes racing from across the group to hurl himself on top of her. She just glances irritably at him over her shoulder and goes on scratching through the leaf litter. If she's interested in mating, she'll slink quietly away from the group, trailing him behind, his nose glued to her tail.

As you can imagine, by the end of the oestrus period, alpha males look gaunt and haggard. Their fur stares and you can almost see the dark rings under their eyes. Perhaps this is why they throw in the towel. On about the fourth day, they simply let the second-in-charge male take over. By the fifth day, it's the third male that's escorting her, and so on down the hierarchy. Even the little nine-month-old males will eventually indulge in a bit of hanky-panky with Mum. Is this how she guarantees that everyone helps raise her pups? 'This one is yours, dear.' Lucky they haven't figured out how to do DNA testing...

Alpha females are not backward in coming forward. Jasmine, Halycon's reigning monarch, invites passersby to sniff the goods.

Thursday, August 26, 2010

Mother’s milk... and Dad’s too

This post is not about elephants. Or lions.

I am NOT going to talk about yesterday's dawn-chorus of roaring, or being woken this morning by the excited, come-hither calls of spotted hyenas.

In fact, today's post is about the very epitome of peace: the dove (well actually a pigeon, but who's splitting hairs).

You see, I've been spending the last few days with Ecthelion, whose favourite termite mound is shaded by a fruiting rock fig.

The roots of the large-leaved rock fig (Ficus abutiliflora) can split rocks and plummet down 60 metres/yards to tap underground water sources.

I arrive each morning to a festival of birds: hornbills, starlings, louries and pigeons, all hopping about among the leaves, gorging themselves on the tiny figs. With squawks of protest, most of the revellers flee as I approach, but the African green pigeons (Treron calva) are made of sterner stuff. They simply shuffle sideways or crane their necks to peer down at me from between the leaves. Dressed smoothly in soft greens, and decorated with epaulettes of lavender, they're designed to blend into the foliage. To aid the disguise, they've developed a preternatural stillness. I find it disconcerting. Their persona is not improved by their unnerving, ice-blue eyes, or a bill – blood red and sharply hooked – that hints of deeds far more sinister than fruit-munching. And when viewed from below, they reveal a hitherto unsuspected brazenness: brilliant yellow leggings and scarlet toes.

Would you trust this bird? Photo by Johann du Preez.

After a while the pigeons tire of glowering down at me and go back to clambering silently about the branches. When I'm not looking, they'll even hang upside down, parrot-like, to pluck the small spherical figs from the branch tips. If I move suddenly, they burst from the foliage in a clamour of wing clapping, and fly - swift and straight - to a nearby dead tree. Here they line up on a sun-drenched branch to soak up the warmth and delicately preen one another's feathers.

Like all pigeons, African green pigeons have some weird habits. Not the least of which is feeding their chicks on milk. No they don't steal it, they brew the stuff themselves.

Midway through incubating their eggs, something strange begins to happen to both Mum and Dad. A rush of the pituitary hormone prolactin (the same hormone that prompts milk production in mammals) makes the walls of their crop thicken up and blood vessels invade the area. By time the first chick scrambles from its shell, the adults' crops have trebled in weight and are sloughing off cells to form a cottage-cheese-like goo, called 'crop milk' or 'pigeon milk'. The newly hatched squabs (the in-house term for pigeon chicks; personally I'd go back into my egg if someone called me a squab) feast exclusively on this for the first few days, thrusting their heads right inside the parents' beaks to gobble down the goodies.
Pigeon milk compares well with mammal milk; it's very rich in protein, moisture and fat, but contains no carbs. And it's more effective at promoting rapid growth than the milk in your refrigerator. Parent pigeons, however, only produce the stuff for the first week or so, and then they wean their little ones on to solids.

Enjoying the morning sun. I try not to identify with this species' plump shape... I'm sure I'll lose weight once the summer comes... Photo by Arno and Louise Meintjes.

But why do pigeons go to all this trouble? The only other birds known to feed their kids on throat secretions are flamingos, who cough up a mixture of blood and fat. But flamingo chicks need to grow fast if they're to avoid being left high and dry when their shallow breeding pools dry out. Baby pigeons face no such deadlines.

The answer seems to be two-fold. Firstly, pigeon eggs are unusually small (relative to the size of Mum) and secondly, little pigeons are very well developed when they eventually hatch. As a result, pigeon chicks have squandered their entire food store (the egg's yolk) by the time they hatch. This is not normal. Most baby birds emerge with up to a third of their yolk intact. With this rich source of fat and protein embedded in their tummies, the chicks of other species don't eat for their first few days, giving their gut a chance to adapt to solid food. It's thought that pigeon parents cover this 'down-time' for their hungry chicks by coughing up pigeon milk.

 Figs are the favourite food of African green pigeons (Treron calva) who dine almost exclusively on fruit. I was going to call them fruitarians but apparently strict fruitarians (and some vegans) boycott figs because they contain insects! NB: figs are pollinated internally by a symbiotic wasp who ultimately dies inside the fruit.
Photo by J. Muchaxo.

Wednesday, August 18, 2010

Arrgh! More megafauna...

Today I meant to write about a small, innocuous bird, but circumstances have overtaken me.

By this I mean I'm feeling too jittery to sit and think about anything with feathers (no offense to any ornithologists out there).

You see, this afternoon the dogs and I inadvertently strolled into the middle of a herd of elephants.

This has never happened to me before. Although I've met elephants on foot in the past, I've always been on 'elephant alert' (i.e. hyper-anxious and wary due to obvious elephant occupation) and have spotted the creatures before we were actually nose to... trunk.

Not today. Unfortunately, I'd been lulled into believing the wanderers had gone home. On Saturday, the main road leading back toward Kruger had been generously festooned with elephant droppings, and I'd made the obvious (erroneous) assumption.

It's easy to know where elephants have been by the massive, circular foot prints, broken branches, felled trees, lakes of urine, prodigious heaps of dung (100 kg or 220 lbs daily), overturned vehicles and trampled dog-walkers. They also pong (the elephants, and - come to think of it - trampled dog-walkers). It's much harder to know where they're going. Photo by Arno Meintjes.

So today, as the dogs and I ambled along the track beside the riverbed and I was wondering what kind of soup to make for dinner, we rounded a corner to meet three large elephants marching along the track toward us. They were walking closely in single file and were only 15 meters/yards ahead. We all stopped dead and stared at each other in amazement. The two elephants at the rear stuck their heads out to gawk at me around the lead animal, and they all flared out their ears. My field of view became entirely elephant-filled. I immediately swivelled around and began walking quickly back the way we'd come; a decision the dogs seemed more than happy to comply with. Glancing over my shoulder, I was hoping to see the elephants reacting in the same way. They weren't. They were still striding along the track and were rapidly closing the (very small) distance between us. At this point I thought, 'F*#! the don't-run policy', irrationally shouted "Run!" (a command unknown to my bewildered dogs) and took off down the track. Of course, I had a snowflake's chance in Hell of out running them if they gave chase, but I was praying they'd not had a bad day. Fortunately I think my shout startled them, because - risking a fleeting look back - I saw them swing off the track and stride away up the hill.

What you don't want to meet while walking the dogs.

I was just slowing down to catch my breath (running is NOT my forte), and the dogs were gazing at me incredulously (they'd never seen me take flight before), when an elephant clambered up the bank on our left, and lumbered on to the track eight metres/yards ahead of us. We stopped running. We all stared. I thought, 'There's nothing I can do'. I didn't think about the trusty pepper spray in my pocket (which wouldn't reach an elephant's eyes; maybe its trunk-tip? On second thoughts, getting up the nose of an enraged elephant probably wouldn't help matters).

The elephant looked disgruntled, swinging back and forth as it shifted its weight from one foreleg to the other. It flapped its ears and then jogged across the track, tail curled in anxiety, to retreated up the hill to our right. It wasn't very big (as elephants go); in fact, it was only a youngster. A youngster with a Mum? Where was she?? I was starting to panic again, trying to check every nearby bush and boulder for rampaging matriarchs. The youngster was now walking parallel to the track but less than ten metres away from it. Figuring that he, at least, didn't appear belligerent, and fearing that his (highly protective?) Mum could burst forth at any moment, I dragged the dogs back into a run, hurtled down the track past the young elephant and raced on towards home.

Quite a workout and NOT something I want to do every day!

What you NEVER want to meet. Photo by Jussi Mononen who's a braver soul than I.
NB: in-focus images of charging elephants are as rare as hen's teeth.

Thursday, August 12, 2010

Step-dads from Hell

"Better a serpent than a stepmother."
     Euripides (480-406 BC)

Over the millennia, step-mums have received some seriously bad press. From Cinderella to Hansel and Gretel, our folklore is brimful of stepmothers behaving badly. But where are the wicked step-dads? Stepfathers have gotten away with murder. And of course they still are, if you happen to be a lion.

Alright, I admit it, this post is about lions.  Again.
Not that I'm becoming obsessed by the creatures...

It's just I've got a horrible suspicion they've followed me home (my house is six kilometres from my study site, as the lion pads).
Just paranoia? Well if so, I'm not the only one. Last night a herd of waterbucks (shaggy, horse-sized antelope) settled down to sleep 12 metres (39 feet) from my backdoor. There they all sat, nonchalantly chewing their cuds, while the TV blared and my lights blazed, and the dogs yapped at the porcupine and I hollered at the dogs. This is NOT normal waterbuck behaviour. Even the dogs knew something was up, and pointedly ignored them (Wizard's aberrant feelings about waterbuck are elucidated here).

It reminded me worryingly of my visit to Yellowstone National Park, where I spent several days fruitlessly searching for an elk (a species I'd never seen) before stumbling upon dozens, all sitting about calmly amid the shops, cars and people inside the (wolf-free) camps. Were the local waterbucks using me as an anti-predator device? If so, it didn't work. A couple of hours after the dogs and I had retired, we were startled awake by a volley of explosive alarm barks and the wild crashing of waterbucks taking flight... from something...

On average, a lion eats 5-7 kg (11-15 lbs) of meat a day. But when push comes to shove, it can put away 50 kg (110 lbs) at one sitting (that's 30% of its own weight). Phew! Photo by Arno and Louise Meintjes.

The two lions that may, or may not, be wandering around outside my house are not step-dads. In fact, it's pretty safe to say any male lion you see lounging about is not a step-dad. When a male lion has step-kids, he's busy: hunting them.

You see, at the heart of every lion pride is a sisterhood of lionesses (mothers, sisters, aunts, nieces) who happily fix dinner together and suckle one another's cubs. The pride males are outsiders; war-hardened fighters who've forged alliances to overthrow their rivals. Now you probably already know that when new males take over a pride, they kill any cubs less than 12 months old. This isn't just wanton violence: freed from the needs of their cubs, the pride's mums will be ready to mate with their offspring's murderer in just a few days or weeks. What I hadn't realised, is the precariousness of this system.
The problem is, a lioness only gives birth once every two years (all being well) because it takes 18 months for her ankle-biters to learn to fend for themselves. But the average tenure of a pride male is only two years (at least in the Serengeti, where the long term studies have been done). So even the most paternal, fun-loving and altruistic step-dad simply can't afford not to get blood on his paws. Unless he rids the pride of dependent cubs, he won't have enough time to rear his own brood before his successor rushes in and murders them. It amazes me that any cubs survive at all (as it is, only 50% make it to 12 months of age).

Like an exclusive coffee circle, the number of adult lionesses in a pride is fixed (by the size of the pride's territory) and stays stable, year after year, even though individual members change. If the circle is full, the pride's daughters must leave home, but if places fall vacant - and there are no female cubs to fill them - even unrelated lionesses are allowed to join. Photo by Arno Meintjes.

Of course the whole system is pretty poxy for the lionesses too; after all, they invest much more in the cubs. Sometimes the girls will band together and successfully drive out the new males, and occasionally a mum will go into exile to save her cubs. But even when the wicked step-dads have done their evil deed, the lionesses still have some tricks up their... er... fur. After a change in males, the lionesses go through three or four months when they're very interested in sex. But they don't actually enter oestrus or conceive. This honeymoon period, not only encourages the males to hang around (rather than mating and abandoning the pride) but also allows time for any bigger and better males that might be lurking in the area, to overthrow the incumbents, before the girls have invested in their cubs.

It's been calculated (field biologists are a sad lot) that lions copulate 3000 times for every cub that survives to yearling age. Ovulation in lady lions is brought on by love-making, so he's got to get it right, if he wants to be a dad. Photo by Arno and Louise Meintjes.

Of one thing you can be sure, if lions have folklore, wicked stepfathers will be a very prominent feature.

A cub of one's own. Photo by Arno and Louise Meintjes.

Monday, August 9, 2010

Megafauna meltdown

The Lion

If you're attacked by a lion
Find fresh underpants to try on
Lay on the ground quite still
Pretend you are very ill
Keep like that day after day
Perhaps the lion will go away

Spike Milligan

Why am I writing a post about lions?

After all, I live and work in a lion-free environment.
In fact, I went to a lot of trouble to find a study site that didn't harbour big and bitey beasts (lions and elephants) so I could walk with the mongooses, fear-free.
So why am I now concerning myself with these massive, great carnivores?

Yesterday, when I arrived at Bugbears' favourite termite mound, I didn't find the usual merry gathering of giraffes. I was a bit surprised, but then I saw why they'd disappeared. Trailing past Bugbears' termite mound were the tracks of two large lions. Now, I'm no great tracker. I tend to waste hours poring over smudgy paw marks, vainly hunting for the forensic subtleties that separate hyena from dog, leopard from cheetah. But when it comes to an adult lion, there's no mistake. Spread your hand as wide as it will go, and you still won't span the pug mark of a lion.

These two males are enjoying a holiday from the nearby Greater Kruger Park. Much to my chagrin, lions tend to wander through here once or twice a year. Generally, once they'v left the park, they don't have much of a shelf-life; sooner or later they chow down on a valued commodity (cow, buffalo calf, sable, roan, etc.) and get themselves shot as a result. I've never yet encountered a lion when on foot and, since Kruger's lions tend to retreat from pedestrians (unless, of course, you stumble upon their kill or cubs), I began to cross my fingers that I'd see them.

But then I met the stump-lions. Stump-lions will be familiar to anyone who's tried to spot lions when game-viewing (i.e. on safari). They're actually close relatives of stick-snakes, and they're normally quite rare around here. Not this morning. It only took a couple of encounters - my heart leaping and the gasping panic tingling through to my finger tips – before I realised I didn't really want to meet a lion on foot after all. I mean what does one do? Obviously retreat slowly, but to where? How wide is a wide berth for lion? With more than half a kilometre of bush between myself and the car, there's no 'place of safety'.

It was while I was pondering these weighty questions, that I realised my stump-lions weren't even realistic. They were more like stump-St Bernards. Thanks to our familiarity with large dogs, we all have a mental picture of big predatory mammals, and most wild carnivores (from jaguars and wolves to hyenas and cheetahs) fit the bill. But lions are outside the box. Put simply, lions are BIG. And I'm not just talking Great Dane/Irish Wolfhound big. The shoulder height of your average male lion is 1.2 metres (4 feet) which is also my shoulder height (give or take an inch). And lions weigh three times as much as I do. Oh, and did I mention their length? From nose tip to rump, males can measure 3.3 metres (11 feet) which is bigger than your average four-seater lounge.

Having scared myself silly thinking about all this, I decided to give up on Bugbears and visit Ecthelion instead. Here I found even fresher lion tracks and was treated to a rousing chorus of yowling by the local jackals (who undertake such performances when they've sniffed out a body).
I spent less time in the field yesterday than perhaps I should have.

To cap off a stressful day, I arrived home to find two sets of massive elephant prints marching down my driveway. A few of Kruger's elephants usually roll up here in the late dry season (searching out fresh greens) but they're a month early this year. Although I think it's wonderful that such animals exist, and l love seeing them mooching past the house, walking the dogs becomes an exercise in courage as we venture forth into Jurassic Park.

Photo by Arno & Louise Meintjes


 Check out the blog carnival I and the Bird (# 131) at The Flying Mullet for lots of intriguing posts about our feathered friends.

Wednesday, August 4, 2010

A young mongoose’s fancy...

Something dark flicks between two boulders. A tiny rustle, a glimpse of movement, and then a streak of black slips away into the dry grass.

This is a dwarf mongoose.
 This is one of MY dwarf mongooses.
 So why is it acting so secretively?

To find the answer, you'll need a calendar. No, flip over a couple of pages. In roughly two month's time, every mongoose group living around here will be celebrating the pitter-patter of little (er sorry... 'littler') feet. Oh, and mongoose gestation lasts 50 days. Get the hint? Well, the mongooses certainly do. Any day now, lots of lady mongooses are going to be out looking for some fun. And the boys are getting ready.

Slinking at my feet are Mistletoe, Holly and Hemp, three young males from Halcyon. They're out on the prowl and, just like young guys loitering at the mall, they assume an insouciant slouch to impress the ladies. We're currently deep inside the territory of a neighbouring group, and the three Halcyon boys are dashing from rock to rock in a commando-style crouch. Their furtive movements have all the subtly of Sylvester stalking Tweetie Pie, and their behaviour screams INTERLOPER, not just to me, but to any mongoose that glimpses them. This is no accident. Despite the very real risks (groups will try to kill any trespasser they can catch), it pays to be recognised.

Rounding a large boulder, I find the three gathered in an excited huddle at one of the neighbours' scent-marking sites. Standing up on their hind legs, they pore over the rock face, sniffing the invisible messages left by prospective paramours and rivals. I can't be sure of the gen their gleaning, but research on other mongoose species suggests they're unravelling the sex, social status, reproductive state and individual identity of anyone that left their signature. The Halcyon lads are keen to know if there are any willing ladies in the group, and how many males are likely to try to see them off.

After several minutes of intense sniffing, it's time to leave some advertising. Hemp turns away from the rock, then swiftly backs up against it, flinging himself into an extravagant handstand. As his hind claws scratch for a toehold high on the granite, he smears a paste of anal gland secretion on to the rock surface. The other two rush to join him and all three teeter awkwardly on their fore paws as they jostle to add their marks. And let me tell you this stuff really pongs: a musky, fox-like scent with a strong overlay of eau de dead animal. To conclude the message to potential lovers, Mistletoe squats down and manages to squeeze out a skerrick of faeces.

Information exchange: Halcyon at a scent marking site.

Reproduction in dwarf mongooses is mostly hogged by the group's dominant pair. These two are responsible for 80 per cent of all pups reared by the group. So what do Halcyon's eager young males hope to gain? The other 20 per cent!
Like princesses marrying for purposes of state, alpha female mongooses don't get much say in who their life-long consort will be. The suitors just battle it out among themselves for the privilege of her paw. But things are different when it comes to romance. Bugbears' reigning monarch, Iorek, routinely sneaks off on romantic trysts with handsome Black (second in command), and when Amethyst (Koppiekats' sovereign) is in the mood for love, she spends a suspiciously large proportion of her time cruising her national borders.

But even if a young male isn't lucky enough to win the favours of royalty, he still has a chance with her subjects. Older subordinate females also indulge in hanky-panky with rovers, and although the fate of their litters is usually unpleasant (at the teeth of Her Majesty), in years of good rain, some of the pups are raised along with the queen's own.

Mongoose on the prowl.


For me, the roving season is a hassle. For example, if the group has encountered the scent of a neighbouring clan the previous day, the young males (like excited children on Christmas morning) chivvy everyone out of bed an hour earlier than I'm expecting, annihilating my plans for data collection. Last year at this time, I unwisely tried to undertake feeding experiments (to see if hunger affects a mongoose's contribution to sentinel duty). The experiments worked fine when I fed the girls, but whenever I gave a free meal to one of the lads, I could almost see him rubbing his paws together in glee. He'd then disappear for the day, off roving at the neighbours.

It also makes me feel glum because rovers usually end up leaving permanently once the rains come. Although it's perfectly natural for males to leave home at two or three years of age (to join another group or try to establish one of their own), it's sad to lose animals I've worked with all their lives.
But still, it isn't all bad news. Last week, as I was driving home, a rover ran across the road ahead of me. Recognising a scar on the animal's side, I screeched to a halt, and was delighted to meet up again with Merry, a male who'd emigrated from Ecthelion with six of his brothers, more than 18 months ago. Despite the long absence, he came running straight up to me when I called, and then sat by my feet expectantly, licking his lips!
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