To be woken by a wolf whistle is a novelty not many enjoy, but there it was, rousing us from sleep with a flirty insistence. Later, as the sun climbed to warm the top of the jungle canopy, the whistle of the screaming piha bird, the Amazon's signature alarm call, was drowned out by the ominous rising, rolling roar of the red howler monkey, chasing us across the peaty rainforest floor like a haunting. By noon the ear-splitting screech of scarlet macaws could be heard overhead and, following a deafening downpour of rain, a bell-bird announced the sunshine with the oddly incongruous whine of a garden strimmer.
Noise pollution may have become an irritating part of modern life but in the rainforest and savannah of the Rupununi, a remote region in southern Guyana, it's a case of sound and fury signifying, well, everything. What time it is, when the rains will come, when they will end, and when the sun will make the ground steam and mists rise into the trees with such primordial potent that each morning, you swear, must surely be the first on earth.
As dusk falls we emerge from the day's jungle trek into the gaping expanse of the savannah, which meets Guyana's Amazon with the neat abruptness of a tightly sewn patchwork. Poking our heads from behind the dense wall of green we're greeted by the "peekaboo" call of the kiskadee bird. The title song of Guyana's grasslands is accompanied by yet another unmistakable sound: Sydney Allicock, the Rupununi's most colourful political figure, gearing up for an evening of campfire rhetoric.
Sydney Allicock, Amerindian political campaigner and village touchau (chief) is also a hotelier - something of a rarity in this country where tourists are sighted less frequently than the native jaguar, giant anteater and elusive harpy eagle. We are the only guests staying in the simple huts Sydney has built within his village of Surama, a pioneer destination for community-based tourism. His wife welcomes us with a dinner of spicy salt beef, rice and plantain. We eat as lightning flashes across the savannah, cattle-grazing land that remains sun scorched for much of the year, the sky-wide strobes accompanied by blinking fireflies. Sydney warms easily to his foreign audience. "Beef is vegetarian," he deadpans, over a rum and coconut water. "It's just reconstituted grass." For someone whose native Macushi Indian language has no words for please, thank you, sorry or friend, Sydney is an astoundingly compelling orator. A small-town Churchill clearly bound for great things, not least great one-liners. "Watch out," he calls, as we dash for our net-covered beds. "Fireflies are just mosquitoes, with flashlights."
Just before sunrise, as the clouds of storm termites have cleared but the fug from the rum hasn't, we trek across springy tufts of goat's beard savannah grass back into the jungle. In the blue-grey of almost dawn we silently navigate the Burro Burro River in dugout canoes of purple heart wood. Bats swoop overhead, and giant buttress roots of mora trees cast gothic shadows that we mistake more than once for lurking caiman. Later, back out on the savannah, in the searing sunshine that comes after yet another downpour, we visit Surama's school, maintained in part by local tourism money. Here, 100 children greet us, standing to introduce themselves individually before singing a collective welcome song gathered under the school motto that reads "be regular be punctual", which leaves us wondering how fibrous school dinners are in these parts. Inside, dog-eared British colonial exercise books entitled How to Play Cricket lie beside picture dictionaries of Macushi words and a Caribbean region public information poster depicting a loving father and son and the words "children need daddies too".
Just where are we? In a straw poll of well-travelled friends, many couldn't place Guyana on a map. Once here the place somehow still refuses to be pinned down. Conan Doyle found his Lost World in Guyana, in the table mountains that border Venezuela, surrounded by savannah that could be plucked out of East Africa. Further north where the Amazon meets the Atlantic, native Indian villages give way to those first settled by indentured labourers from the Indian subcontinent and liberated Afro-Caribbean slaves, the sugar cane workforce on which Guyana's British and Dutch colonies were founded.
We began our journey in Iwokrama, a jungle conservation reserve where, due to its proximity to the Brazilian border, Portuguese is heard as often as English. Here resident biologist Waldyke Prince (aka Wally) distracts our culturally confused minds with a forest trek, pointing out local plant cures for such grave ills as jaundice, arthritis and malaria, nonchalantly swatting aside spider webs hanging hammock-like across our path.
Later we observe all this from above, on the reserve's jungle canopy walkway strung 100ft above the forest floor. Sadly no one in our group is part of the fortunate one in three visitors who spot jaguar, but the promise remains as we travel south along the region's red dirt road cut deep into the jungle. By road and flat bottomed "Balahoo" river ferry, to transport our Jeeps, we follow the route colonial cattle herders made to export their livestock, only in reverse, from Guyana's northern Amazon deep into the southern savannah.
Beyond Iwokrama and Surama lies Rock View, a former cattle station hub for the region's pork knockers, the name in which Guyana's self-made men once rejoiced. This former community of vaqueros (cowboys), gold-panners and balata bleeders (Guyana's version of the rubber tree) now operates as a dairy farm and wildlife-watching base. Here, morning hikes to see the rare cock-of-the-rock bird flash its scarlet feathers in a courtship display that's more like a war dance, are followed with afternoons lazing by the rustic stone swimming pool or watching resident leather craftsmen fashion hammocks out of cowhide. Rum-fuelled evenings are hosted by the owner, Colin Edwards, a British expat who came to find his fortune in Guyana's diamond mines and now works closely with Iwokrama to preserve and protect the country's natural resources through community tourism. Over sundowners Colin's cut-glass English accent can be heard making an inventory of the British dignitaries to have visited this region (various members of the Royal Family, Mick Jagger, Evelyn Waugh) and I have to remind myself we're not in 1940s Africa but a country in present-day South America.
More shadows of white mischief can be found further south at Karanambu Ranch where hostess Diane McTurk presides over her Giant River Otter rehabilitation centre. Around 6ft tall and looking as if crafted from the bush itself, it's easy to see why Diane, the descendant of Scottish colonialists, has attracted the attentions of David Attenborough, Gerald Durrell and numerous travel television teams. Dressed in Jackie Onassis sunglasses and headscarf she wades out to greet our boat, followed by a pair of baby otters making more racket than our outboard motor. At sunset, after the initial flurry of otter attention has subsided and our defiance against the menacing bite of the region's kaboura fly has grown, we take another boat ride, this time through a dense forest eerily flooded by wet-season rain. In a clearing thick with Victoria amazonica water lily, Guyana's national emblem, we watch the giant white flower do its nightly unfurling act. The following dawn this unique sight is almost topped by yet another first for most of our group when, in an area of rolling grasslands, vaqueros riding barefoot manage to locate a 6ft long giant anteater excavating its breakfast from one of the savannah's red termite mounds.
It's hard to imagine that such exotic experiences could be bettered, but leaving Karanambu in an 18-seater plane we are treated to yet another sight that leaves our group gaping like a family of Amazon spider monkeys. Flying over Guyana's as yet untouched rainforest, we put down at Kaieteur Falls where the winding 400ft wide Potaro River takes a sudden 741ft plunge to make Kaieteur, the largest single drop waterfall in the world. But this is no Niagara; as ever in Guyana, besides the resident thousand-strong flock of starlings taking a near suicidal shower in the falls, we are Kaieteur's sole audience. Its thundering roar, the last performance from Guyana's vast orchestra, is still ringing in my ears.
The writer travelled as a guest of BWIA (0870 499 2942; www.bwee.com) and Reef and Rainforest Tours (01803 866965; www.reefandrainforest.co.uk). BWIA offers daily flights from Heathrow to Georgetown, (via Barbados or Trinidad) from £883 return.
Reef and Rainforest Tours offers 14-day tailor-made wildlife tours of Guyana starting at £2,275 per person including international flights, accommodation, transfers, transport, most meals and guided activities. These tours are often combined with beach breaks to nearby Trinidad and Tobago.
Wilderness Explorers (020-8417 1585; www.wilderness-explorers.com), a private Guyana-based tour company with a London office, can provide general information in lieu of a Guyanese Tourist Board presence in the UK.
The Latin American Travel Association (020-8715 2913; www.lata.org).