Beneath my supersonic feet I can hear howler monkeys in the trees launching a dawn chorus that sounds worryingly like a pack of hungry wolves. I’d look down to check but I’m not very good with heights... or wolves. To round off the complete surrealism of this scene: directly in front of me rises a large, perfectly shaped volcano, clouds clinging to her summit. She grumbles and growls angrily, occasionally hurling a fiery volley of rocks into the air that shatter in fierce balls of sparks on her steep slopes before rolling down spitting and smoking.

I’m really picking up speed now and I start to panic. I try to remember what Kenneth, my unlikely-named Costa Rican tutor, had told me about slowing down in the two-minute “safety” chat we had. I’m pretty sure that it was something about lowering my legs and twisting left to right. He definitely said not to touch the cable. Or did he? Maybe I did have to do something with the cable? It’s tricky thinking clearly about life-and- death decisions at this speed. What the hell am I doing this for anyway? I’ve got children, for Christ’s sake.

I blame my brother-in-law. He’s a property developer on the Pacific coast and he kept telling me how wonderful this country is. I didn’t really know anything about it. My scratchy knowledge of Central America incorporated tinpot dictators, about 50 revolutions and good coffee.

Costa Rica scored one out of three: no army since 1949, instead the money’s been poured into education and health, making for an extremely progressive, democratic country. For such a small country (you can actually see both the Caribbean and Pacific coasts from its highest point) it boasts an extraordinary topographical variety: rainforest to beach in three short hours.

Suddenly, the volcano belches again, violently, and I can feel the wire shake as the tremors hit the deep foundations of the pylons holding me up. Is this normal? Everyone seemed fairly relaxed about it at breakfast — apart from me, that is, trying to look cool while negotiating a shaky spoon of gallo pinto (rice and beans) into my mouth.

A multicoloured bird soars past me, a little too close for my liking. It’s definitely on some sort of recce trip. It’s wondering what this podgy mammal is doing flying through his neighbourhood and how the hell it’s staying airborne. I try to calm down, work out what type of bird it was. Not that I care, but it might help — everyone here is so obsessed with birds it’s like being on Bill Oddie’s stag weekend.

Ecotourism is the main draw in Costa Rica and you notice it from the moment you land. Taking a look at some of my fellow travellers at the airport, it became clear that there was something very different about a large percentage of visitors.

They were not your usual tourist material. There was a preponderance of spoddy, often bearded couples sporting matching safari outfits with complicated contraptions wrapped around their bulging bodies that, on closer inspection, appeared to be for stabilising binoculars. Another minute of unsubtle nosing around and I hit pay dirt: the telltale bird-watching books hanging in the loose net pockets of their luggage. Geeko-tourists.

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I remember something my brother-in-law told me about this country: “Costa Rica is a place for Wannabes and Gottabes.” I nodded wisely and wondered what on earth he was on about. It was obvious that the wannabes were people who, like him, stumbled upon the amazing beauty of the Pacific coastline and were trying to make a living out of tourism. I now realised that the Gottabes were the roaming gangs of natural-science students ostracised from “normal” society and forced to spend their holidays roaming the forests of Costa Rica making notes on macaws and hummingbirds — literally getting wood from woodpeckers.

The rainbow bird strafed me again. Is it a toucan? How the hell would I know? God I could do with a Guinness right now, all cold and foamy... I can’t believe that I’m thinking about a drink at a time like this. I need to get a grip. I’ve got another visitor: an enormous butterfly has somehow managed not only to keep up with me but to land on my harness. It’s sitting there serenely stretching its browny-blue wings. I have to admit it’s an impressive sight.

The five fake blue eyes on its left wing are, apparently, used to scare off predators. Right now the little spotty bastard is using all five of them to indicate to me that it can hop off at any time and float away. This option is, sadly, not one available to myself. I swear one of the azure-blue eyes just gave me a conspiratorial wink. Am I hallucinating? This whole thing is just too weird. I’m going to stop this travel- writing stuff. Hunter S Thompson never felt like this.

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