Masked weavers revealed

If you’ve come here expecting an exposé on the criminal activities of textile workers, you’re in for a disappointment.

This post is about something much less exciting: SEX.

Now I don’t know how you choose your sexual partners, and I wouldn’t dare suggest that anything is inappropriate... But whatever traits turn you on, you can be certain that somewhere out there someone with feathers is already doing it.

Regardless of whether your interest is sparked by a lover’s apparel, their talent in the performing arts, their real-estate holdings, the colour of their footwear (you’d have to be a real booby to go for this), their artistry or – let’s get down to it – the size of their gender-specific endowments (excuse me, I was referring to tail plumes), your tastes don’t differ from millions of birds.

But there’s one group of feathered critters whose predilections are genuinely perverse.
For them, sweaty singlets and wolf-whistles are all the go.
That’s right; construction workers rule the roost in weaver society.

Now if DIY skills were the currency of ardour in humans, I’d be destined for barren spinsterhood (hey, wait a minute, I am a barren spinster...). Although home-building skills may seem a tepid way to woo a lover, it hasn't held back weavers. Around 62 species (all in the genus Ploceus) are out there busily knocking up their edifices, mostly in Africa but also in southern Asia too.
And with all the recent rain, a large proportion of these creatures seem to be doing it right here.

A macho lesser masked weaver (Ploceus intermedius) kitted out for love. He only dons his mask - in bad-boy warning colours - when the talent weather is hot.

Gathering in rowdy hordes in trees overhanging water, the local lesser masked weavers are in a state of frenzy.
Males dash back and forth with long grass stems trailing from their bills, and there’s a constant buzz of chirping and squawking, which swells periodically into a goal-score roar when a flirtatious chick drops by.

Before a weaver on the make can fabricate an alluring boudoir, he must first stake out his own patch within the colony. This involves lunging at intruders and grappling tooth and nail beak and talon with any persistent rivals. Once he's scored an exclusive building site, Romeo gets to work weaving a collection of finely-laced, retort-shaped homes (if you're not a closet alchemist, a retort is a glass flask with a spherical base and a long tapering neck that's bent downward; it’s designed for distilling things). The male’s goal is to distil a harem of lady tenants who’ll considerately raise his chicks for him.

Using only fresh green grass, plucked straight from the clump, he twists and pokes and pulls, entwining the strips intricately, while emanating an air of intense and bad-tempered concentration. As the grass strands dry, they shrink, tightening up the weave and strengthening the structure. But with nest sites at a premium, a male can’t afford to keep any untenanted premises on his books, so pissed-off males demolish nests that have proven unpopular.

In the quest for the most beguiling nest, males also indulge in a bit of landscape gardening, clipping the leaves from all branches near their homespun abodes. This - along with the nest’s funnel entrance - is thought to make things tricky for those iniquitous nest robbers, the harrier hawk and the boomslang.

‘These damn things just keep growing BACK!’

‘Well, that’s an improvement anyway.’

When a lady weaver approaches, all the males get very excited, snatching up a grass stem and dashing to their best construction. Hanging from the base, a hopeful male flutters his wings enticingly, sticks his tail out horizontally and points his beak suggestively into his nest. He also chirps in a frenzied manner (precise translation unavailable, but I daresay you know all the usual pick up lines...).

‘If you come in here, you can see the playroom has a northerly aspect...’

‘I think someone should really tell George that the can-can is so yesterday.’

For any inept handymen out there, consoling themselves that bird's nest-building skills are hardwired anyhow, let me disabuse you. Male weavers must learn their trade.

While yearling females rush headlong into motherhood, their brothers eschew sex for a year or two. These young bloods get together in colonies of their own where they can work on their erections without censure. Experiments show that if adolescent males are deprived of this early practice (by denying them building materials), their DIY skills are seriously retarded. However, just like riding a bicycle (which you may be please to know male weavers cannot do), building prowess - once learned - is never forgotten; even if callous researchers blockade building supplies for years on end.

Slipshod workmanship will not escape the eye of a lady lesser masked weaver. However, the landlord's only responsible for creating the nest’s outer walls; all soft furnishings must be provided by the tenant.

But what does today’s lady weaver seek in a family residence?

Researchers working with village weavers (Ploceus cucullata) found that mothers-to-be aren’t swayed by outward appearances; neatness and closeness of weave are, after all, mere superficialities. What counts is the strength of the materials and the newness of construction. The girls will have no brook with old, browned off nests and, like master chefs, they’re canny at detecting what’s fresh and what’s not. Merely painting a good nest brown will not fool them, although the same cannot be said for males, who are three-times more like to demolish a nest if it’s been artificially dyed brown.

‘Hmm, I do like a Paspalum veneer; it gives a much fresher ambience than the traditional Poa finish...’

‘Yes Martha, I’ll join you in a mo’. That little minx Estella is looking real interested in Number 3.’

I’m stuck in a rut

All around, the bush is reverberating with deep snarling roars and growls.

Imagine the rumbling growl of an attacking Rottweiler, only crank up the volume until it's audible 2 km away. Oh yeah, and there's the occasional explosive snort too.

For the uninitiated these bursts of apparent violence are quite intimidating. I've become accustomed to my new volunteer assistants returning prematurely from the field, ashen faced and muttering, "Er... um... I heard this growling...".

Lions?  Wild dogs?  Fighting hyenas?   Impala.

Impala (Aepyceros melampus) are the most numerous antelope in southern Africa, with more than one million living in the region. And right now it sounds like they're all just outside!

Each May (synchronised between the two full moons) the local impalas mate. Now, before you start thinking that impalas have wildly exotic sex lives, the mating itself isn't noisy. It's the males arguing over breeding territories that create the racket. A study of rutting males at Sengwa, in Zimbabwe, noted 180 roaring displays in just one hour, on a romantic moonlit night.

Displacement grooming is frequent in territorial conflicts, as males waver between attacking their rivals and playing it safe (just as humans scratch their heads when making up their minds).

In East Africa, male impalas hold territories all year round, but here in southern Africa, they relax in mixed-sexed herds for most of the year. However, as the short, intense breeding season approaches, their testosterone levels soar and they go into a frenzy of aggressive competition. In a bid to stake out breeding territories (of around 8 – 13 ha), they use macho displays to intimidate rivals, standing very erect while flexing their neck muscles, tossing their heads, roaring, horning vegetation and even flicking their tongues in and out like professional punk-rockers.

Actual horn-clashing fights are rare (occurring in around 7% of conflicts) and males have a 'dermal shield' of thickened skin that protects their head and neck from stab wounds. Photo by Dougie Cunningham and borrowed from here.

Males that fail to gain a territory retreat to bachelor herds, where they spar with one another to establish a pecking order. Only those at the top of this hierarchy go forth to challenge the territory holders.

Territorial males spend up to a quarter of their time tending the females that pass through, chasing them into the territory's core, tasting their urine for signs of oestrus and, of course, mating. They also patrol their boundaries, face down trespassing neighbours and fight off challengers. As a consequence, they rarely get a chance to feed or sleep, and quickly exhaust themselves. Their average tenure, during the peak rut, is only 8 days. Once they're ousted by a rival, males limp back to the bachelor herd (rejoining at the bottom of the hierarchy) to regain weight and recuperate.

Horning vegetation is not only an impressive visual display, it leaves behind a smear of strong-smelling secretion, from the skin on the male's forehead, that indicates his status.

Female impalas show little interest in the males' squabbles, wandering from territory to territory. Although the population is female-biased, with 1.5 to 2 females for every male, most of the mating is monopolised by just a handful of prime territory holders.