Delight then darkness for chaotic Guinea-Bissau

Sometimes, life for the traveller offers little choice. I'm about to catch the only public transport off the isle of Orango for another week. A fight breaks out on the beach over the price for transporting cargo; the captain of the leaky wooden pirogue has been drinking palm wine since early that morning, but he's cutting a pretty sharp deal.

In a lull in the general chaos, I scramble aboard to find a niche among the vast rolls of matting, containers of palm wine, heaps of luggage, vats of food, countless women, children, chickens and one indignant goat.

At last the overloaded boat sets out for a neighbouring island. The sea is mercifully calm. But as Uno's golden, green-capped shores draw near, I stare at the crowd that awaits us. No. Surely not...? Erm, yes. This is Uno's only transport, too, and mayhem ensues as another 50 people pile on with their luggage, palm wine, children and chickens; completing the cargo are five shrieking pigs who seem to sense that this journey might be their last.

I try not to think that they could be right. Everyone knows it's madness; palm wine changes hands and I knock some back, trying to ignore the furious bailing out that's going on. I reflect instead on the beauty of Orango, where I've watched flocks of pelicans and flamingos, wound inland along pristine mangrove creeks, and followed the tracks of rare salt-water hippos. Now I'm joining the villagers as they converge on the isle of Bubaque, where the annual carnival is due to kick off in a few days' time.

The carnival, along with these unique Bijagós islands situated off-shore, is what has drawn me to the tiny, impoverished country of Guinea-Bissau on the west coast of Africa. Traces of Portuguese architecture still dot the nation; Lisbon ceded control of Portuguese Guinea in 1974, and since then a series of coups and a brief civil war have impeded progress.

The infrastructure is in tatters, with no running water nor mains electricity; the government is mired in corruption. After surviving the journey back to Bubaque, I take a walk into the forests through cashew groves and past enormous kapok trees, and hit upon a village of thatched huts where a group of girls are laughing and shouting around the water pump.

"Brancooo!" they cry gleefully, on spotting me.

I grin, having very little Creole, and wonder whether I'll be breaking some taboo if I proceed through the village – animism holds strong here, and sacred spots are dotted everywhere. But Bijagós hospitality kicks in. One of the girls jerks her head at me and I follow her.

We sit down outside her hut and she shows me what she's been making – a tree-bark saia, or skirt, the traditional dress of the island women. I watch as she rubs the fibres into hundreds of delicate ropes between her palm and thigh. Her name is Feena and, after a while, she disappears into another hut where I spot a pot bubbling over a fire. She emerges with two bowls of thick bean stew – one for the children who have gathered around us, and one to share with me. We tuck in; it's rich, slightly sweet, and delicious.

Lunch over, we're off around the village, meeting her mother and sisters; then I'm taken along to join a bunch of young guys who are making their carnival gear of intricate wooden masks and helmets.

It's been a perfect day, and it's followed by another: in complete contrast, I cycle to an immaculate white-sand beach that stretches as far as the eye can see. There's no one there; just a few cows, and grey hornbills mewing in the forest. And then there's a day spent on the isle of Rubane, where children lead me through the forests and find me snakes, lizards and an owl. All this, and the carnival has yet to begin.

When it does, I have some idea of the effort that has been expended, and it is intensely moving. I see the first round of events on Bubaque, where the islanders compete for the right to go to the parade in the capital, Bissau. (The city's name was appended to the nation to avoid confusion with other Guineas in this part of Africa.)

I join the winners on the ferry, and then it's the big day: the Bijagós islanders' bodies glisten with palm oil and rustle with grass; boys dowsed in mud or white powder re-enact their initiation rites; Fula acrobats from the east gambol in brilliant reds; Pepels rub shoulders with Balantas and Mandinkas; topless dancing girls mingle with Muslim drummers. It's overwhelmingly spectacular but somehow gentle, too.

The crowds are peaceful, curious, and when the parade is over they simply walk the streets, up and down, looking and being looked at.

I'm falling in love with this country, but time's almost up. I'm travelling north towards the border when I hear the news. It comes on the Sunday evening as I share a beer with a Belgian expatriate. Her phone rings. Something's happened in Bissau, she says. Some kind of explosion. People have been killed.

The locals tune in to the radio. Mobile phones ring. Everyone wants to know what's going on; but no one in this beleaguered country wants to believe it. It's nothing, they say. My Belgian friend's not so sure, and by morning she's been proved right. The chief of the army was killed in the explosion and his supporters have blamed the president; they've taken tit-for-tat action and President "Nino" Vieira is no more. He has been assassinated at his home overnight.

I'm due to take a pirogue from Cacheu to São Domingos, back through the mangrove swamps, but now nothing moves. The border has been closed and the streets are deserted. The nation holds its breath, but few shed tears for Vieira, who's been in and out of power ever since independence.

Slowly, as the day goes on, it seems that nothing else is going to happen for now. People let out a long, sad sigh and things start moving again. I cross the border into Senegal without mishap. But Vieira has left more questions behind him than he ever answered. Elections may or may not happen in the coming months. I hope they do, but many in Guinea-Bissau must feel as I did in that leaky, overloaded pirogue: all in it together with a drunken captain, and not much in the way of choice.