It was a windowless thatched building of dressed sandstone blocks, that Daniel Armstrong had built with his own hands almost ten years ago. At the time he had been a junior game ranger in the National Parks' administration. Since then the building had been converted into a veritable treasure house.

Johnny Nzou slipped his key into the heavy padlock, and swung open the double doors of hewn native teak. Johnny was chief warden of Chiwewe National Park. Back in the old days, he had been Daniel's tracker and gunbearer, a bright young Matabele whom Daniel had taught to read, write and speak fluent English by the light of a thousand campfires.

Daniel had lent Johnny the money to pay for his first correspondence course from the University of South Africa which had led much later to his degree of Bachelor of Science. The two youngsters, one black and one white, had patrolled the vast reaches of the National Park together, often on foot or bicycle. In the wilderness they had forged a friendship which the subsequent years of separation had left undimmed.

Now Daniel peered into the gloomy interior of the godown and whistled softly.

'Hell, Johnny boy, you have been busy since I've been away.'

The treasure was stacked to the roof beams, hundreds of thousands of dollars' worth of it.

Johnny Nzou glanced at Daniel's face, his eyes narrowed as he looked for criticism in his friend's expression. The reaction was reflex, for he knew Daniel was an ally who understood the problem even better than he did. Nevertheless, the subject was so emotionally charged that it had become second nature to expect revulsion and antagonism.

However, Daniel had turned back to his cameraman. 'Can we get a light in here? I want some good shots of the interior.' The cameraman trudged forward, weighed down by the heavy battery packs slung around his waist, and switched on the hand-held arc lamp. The high stacks of treasure were lit with a fierce blue-white light.

'Jock, I want you to follow me and the warden down the length of the warehouse,' Daniel instructed, and the cameraman nodded and moved in closer, the sleek Sony video recorder balanced on his shoulder. Jock was in his middle thirties. He wore only a pair of short khaki pants, and open sandals. In the Zambezi valley heat his tanned bare chest was shiny with sweat and his long hair was tied with a leather thong at the nape of his neck. He looked like a pop star, but was an artist with the big Sony camera.

'Got you, guv.' he agreed, and panned the camera over the untidy stacks of elephant tusks, ending on Daniel's hand as it stroked one elegant curve of glowing ivory. Then he pulled back into a full shot of Daniel.

It was not merely Daniel's doctorate in biology, nor his books and lectures, that had made him an international authority and spokesman on African ecology. He had the healthy outdoors looks and charismatic manner that came over so well on the television screen, and his voice was deep and compelling. His accent had sufficient Sandhurst undertones remaining to soften the flat unmelodious vowel sounds of colonial speech. His father had been a staff officer in a Guards regiment during World War II and had served in North Africa under Wavell and Montgomery. After the war he came out to Rhodesia to grow tobacco. Daniel had been born in Africa but had been sent home to finish his education at Sandhurst, before coming back to Rhodesia to join the National Parks Service.

'Ivory,' he said now, as he looked into the camera. 'Since the time of the pharaohs, one of the most beautiful and treasured natural substances. The glory of the African elephant - and its terrible cross.'

Daniel began to move down between the tiers of stacked tusks, and Johnny fell in beside him. 'For two thousand years man has hunted the elephant to obtain this living white gold, and yet only a decade ago there still remained over two million elephant on the African continent. The elephant population seemed to be a renewable resource, an asset that was protected and harvested and controlled - and then something went terribly, tragically wrong. In these last ten years, almost a million elephant have been slaughtered. It is barely conceivable that this could have been allowed to happen. We are here to find out what went wrong, and how the perilous existence of the African elephant can be retrieved from the brink of extinction.'

He looked at Johnny. 'With me today is Mr John Nzou, chief warden of Chiwewe National Park, one of the new breed of African conservationists. By coincidence, the name Nzou in the Shona language means elephant. John Nzou is Mr Elephant in more than name alone. As warden of Chiwewe, he is responsible for one of the largest and healthiest elephant herds that still flourish in the African wilderness. Tell us, Warden, how many tusks do you have in this store room here at Chiwewe National Park?'

'There are almost five hundred tusks in store at present - four hundred and eighty-six to be exact - with an average weight of seven kilos.'

'On the international market ivory is worth three hundred dollars a kilo,' Daniel cut in, 'so that is well over a million dollars. Where does it all come from?'

'Well, some of the tusks are pick-ups – ivory from elephant found dead in the Park, and some is illegal ivory that my rangers have confiscated from poachers. But the great majority of tusks are from the culling operations that my department is forced to undertake.'

The two of them paused at the far end of the godown and turned back to face the camera. 'We will discuss the culling programme later, Warden. But first can you tell us a little more about poaching activity in Chiwewe. How bad is it?'

'It is getting worse every day.' Johnny shook his head sadly.

'As the elephant in Kenya and Tanzania and Zambia are wiped out, so the professionals are turning their attention to our healthy elephant herds further south. Zambia is just across the Zambezi river, and the poachers that come across this side are organised and better armed than we are. They shoot to kill men as well as elephant and rhino. We have been forced to do the same. If we run into a band of poachers, we shoot first.'

'As for these…' Daniel laid his hand on the nearest pile of tusks. No two of the ivory shafts were the same; each curve was unique. Some were almost straight, long and thin as needles; others were bent like a drawn longbow. Some were sharp-tipped tipped as javelins; others were squat and blunt. There were pearly shafts, and others were of buttery alabaster tone; still others were stained dark with vegetable juices, and scarred and worn with age.

Most of the ivory was female or immature; a few tusks were no longer than a man's forearm, taken from small calves. A very few were great curved imperial shafts, the heavy mature ivory of old bulls.

Daniel stroked one of these, and his expression was not simply for the camera. Once again, he felt the full weight of the melancholy that had first caused him to write about the passing and destruction of the old Africa and its enchanted animal kingdom.

'A sage and magnificent beast has been reduced to this,' his voice sank to a whisper. 'Even if it is unavoidable, we cannot escape the inherently tragic nature of the changes that are sweeping through this continent. Is the African elephant symbolic of the land? The elephant is dying. Is Africa dying?'

His sincerity was absolute. The camera recorded it faithfully. It was the most compelling reason for the enormous appeal of his television programmes around the world.

Now Daniel roused himself with an obvious effort, and turned back to Johnny Nzou. 'Tell us, Warden, is the elephant doomed? How many of these marvellous animals do you have in Zimbabwe and how many of those are in Chiwewe National Park?'

'There are an estimated fifty-two thousand elephant in Zimbabwe, and our figures for Chiwewe are even more accurate. Only three months ago, we were able to conduct an aerial survey of the Park sponsored by the International Union for the Conservation of Nature. The entire area of the Park was and the animals counted from the high-resolution prints.'

'How many?' Daniel asked.

'In Chiwewe alone, eighteen thousand elephant.'

'That's a huge population, something approaching a third of all the remaining animals in the country – all in this area.' Daniel raised an eyebrow. 'In the climate of gloom and pessimism that prevails, this must give you a great deal of encouragement?'

Johnny Nzou frowned. 'On the contrary, Doctor Armstrong, we are extremely concerned by these numbers.'

'Can you explain that please, Warden?'

'It's simple, Doctor. We cannot support that many elephant. We estimate that thirty thousand elephant would be an ideal population for Zimbabwe. A single beast requires up to a ton of vegetable matter each day, and he will push over trees that have taken many hundreds of years to grow, even trees with trunks four feet in diameter, to obtain that food.'

'What will happen if you allow that huge herd to flourish and to breed?'

'Quite simply, in a very short period they will reduce this park to a dust bowl, and when that happens the elephant population will collapse. We will be left with nothing – no trees, no park, no elephant.'

Daniel nodded encouragement. When the film was edited he would cut in at this point a series of shots he had taken some years previously in Kenya's Amboseli Park. These were haunting vistas of devastation, of bare red earth and dead black trees stripped of bark and leaves holding up their naked branches in agonised supplication to a hard blue African sky, while the desiccated carcasses of the great animals lay like discarded leather bags where famine and poachers had destroyed them.

'Do you have a solution, Warden?' Daniel asked softly.

'A drastic one, I'm afraid.'

'Will you show us what it is?'

Johnny Nzou shrugged. 'It is not very pretty to watch, but, yes, you may witness what has to be done.'

Daniel woke twenty minutes before sunrise. Even the intervening years spent in cities out of Africa, and the passage of so many other dawns in northern climes, or in the fluid time zones of jet aircraft travel, had not dulled the habit that he had first acquired in this valley. Of course, the habit had been reinforced during the years of that terrible Rhodesian bush war, when he had been called up to serve in the security forces. For Daniel the dawn was the most magical time of each day, and especially so in this valley. He rolled out of his bag and reached for his boots. He and his men had slept fully clothed on the sun-baked earth, with the embers of the campfire in the centre of the huddle of their prostrate forms. They had not built a boma of thorn branches to protect themselves, although at intervals during the night lions had grunted and roared along the escarpment.

Daniel laced up his boots and slipped quietly out of the circle of sleeping men. The dew that hung like seed pearls upon the grass stems soaked his trouser legs to the knees as he moved out to the promontory of rock at the head of the cliff. He found a seat on the rough grey granite knoll and huddled into his anorak.

The dawn came on with stealthy and deceptive speed and painted the clouds above the great river in subtle talcum shades of pink and grey. Over the Zambezi's dark green waters the river mist undulated and pulsed like ghostly ectoplasm and the dawn flights of duck were very dark and crisp against the pale background, their formations precise and their wing-beats flickering quick as knife-blades in the uncertain light.

A lion roared, near at hand, abrupt gales of sound that died away in a descending series of moaning grunts. Daniel shivered with the thrill of that sound. Though he had heard it countless times, it always had the same effect upon him. There was no other like it in all the world. For him it was the veritable voice of Africa.

Then he picked out the great cat shape below him at the edge of the swamp. Full-bellied, dark-maned, it carried its massive head low and swung it from side to side to the rhythm of its stately arrogant walk. Its mouth was half open and its fangs glinted behind thin black lips. He watched it vanish into the dense riverine bush and sighed with the pleasure it had given him.

There was a small sound close behind him. As he started up, Johnny Nzou touched his shoulder to restrain him and settled down on the granite slab beside him. Johnny lit a cigarette. Daniel had never been able to talk him out of the habit. They sat in companionable silence as they had so often before and watched the dawn come on more swiftly now, until that religious moment when the sun thrust its burning rim above the dark mass of the forest. The light changed and all their world was bright and glazed as a precious ceramic creation fresh from the firing oven.

'The trackers came into camp ten minutes ago. They have found a herd,' Johnny broke the silence, and the mood.

Daniel stirred and glanced at him. 'How many?' he asked.

'About fifty.' That was a good number. They would not be able to process more, for flesh and hide putrefy swiftly in the heat of the valley, and a lower number would not justify all this use of men and expensive equipment.

'Are you sure you want to film this?' Johnny asked.

Daniel nodded. 'I have considered it carefully. To attempt to conceal it would be dishonest.'

'People eat meat and wear leather, but they don't want to see inside the abattoir,' Johnny pointed out.

'This is a complex and emotional subject we are examining. People have a right to know.'

'In anyone else I would suspect journalistic sensationalism,' Johnny murmured, and Daniel frowned.

'You are probably the only person I would allow to say that - because you know better.'

'Yes, Danny, I know better,' Johnny agreed. 'You hate this as much as I do, and yet you first taught me the necessity of it.'

'Let's go to work,' Daniel suggested gruffly, and they stood up and walked back in silence to where the trucks were parked. The camp was astir, and coffee was brewing on the open fire. The rangers were rolling their blankets and sleeping-bags and checking their rifles.

There were four of them, two black lads and two white, all of them in their twenties. They wore the plain khaki uniform of the Parks Department with green shoulder flashes, and though they handled their weapons with the casual competence of veterans they kept up a cheerful high-spirited banter. Black and white treated each other as comrades, although they were just old enough to have fought in the bush war and had probably been on opposing sides. It always amazed Daniel that so little bitterness remained.

Jock, the cameraman, was already filming. It often seemed to Daniel that the Sony camera was a natural excrescence of his body, like a hunchback.

'I'm going to ask you some dumb questions for the camera, and I might needle you a little,' Daniel warned Johnny. 'We both know the answers to the questions, but we have to fake it, okay?'

'Go ahead.'

Johnny looked good on film. Daniel had studied the rushes the previous night. One of the joys of working with modern video equipment was the instant replay of footage. Johnny resembled the younger Cassius Clay before he became Mohammed Ali. However, he was leaner in the face and his bone structure finer and more photogenic. His expression was mobile and expressive and the tones of his skin were not so dark as to make too severe a contrast and render photography difficult.

They huddled over the smoky campfire and Jock brought the camera in close to them.

'We are camped here on the banks of the Zambezi River with the sun just rising, and not far out there in the bush your trackers have come across a herd of fifty elephant, Warden' Daniel told Johnny, and he nodded. 'You have explained to me that the Chiwewe Park cannot support such numbers of these huge animals, and that this year alone at least a thousand of them must be removed from the Park, not only for the good of the ecology, but for the very survival of the remaining elephant herds. How do you intend removing them?

'We will have to cull them,' Johnny said curtly.

'Cull them?' Daniel asked. 'That means kill, doesn't it?

'Yes. My rangers and I will shoot them.'

'All of them, Warden? You are going to kill fifty elephant today?'

'We will cull the entire herd.'

'What about the young calves and the pregnant cows? Won't you spare a single animal?'

'They all have to go,' Johnny insisted.

'But why, Warden? Couldn't you catch them, dart and drug them, and send them elsewhere?'

'The costs of transporting an animal the size of an elephant are staggering. A big bull weighs six tons, an average cow around four. Look at this terrain down here in the valley.' Johnny gestured towards the mountainous heights of the escarpment and the broken rocky and wild forest. 'We would require special trucks and we would have to build roads to get them in and out. Even if that were possible, where would we take them? I have told you that we have a surplus of almost twenty thousand elephant in Zimbabwe. Where would we take these elephant? There simply isn't space for them.'

'So, Warden, unlike the other countries to the north such as Kenya and Zambia who have allowed their elephant herds to be almost wiped out by poaching and unwise conservation policy, you are in a Catch 22 situation. Your management of your herds of elephant has been too good. Now you have to destroy and waste these marvellous animals.'

'No, Doctor we won't waste them. We will recover a great deal of value from their carcasses, ivory and hides and meat which will be sold. The proceeds will be ploughed back into conservation, to prevent poaching and to protect our National Parks. The death of these animals will not be a complete abomination.'

'But why do you have to kill the mothers and the babies?' Daniel insisted.

You are cheating, Doctor,' Johnny warned him. 'You are using the emotive, slanted language of the animal rights groups, "mothers and babies". Let's rather call them cows and calves, and admit that a cow eats as much and takes up as much space as a bull, and that calves grow very swiftly into adults.'

'So you feel–' Daniel started, but despite his earlier warning, Johnny was becoming angry.

'Hold on,' he snapped. 'There's more to it than that. We have to take out the entire herd. It is absolutely essential that we leave no survivors. The elephant herd is a complex family group. Nearly all its members are blood relatives, and there is a highly developed social structure within the herd. The elephant is an intelligent animal, probably the most intelligent after the primates, certainly more intelligent than a cat or dog, or even a dolphin. They know – I mean, they really understand …' he broke off, and cleared his throat. His feelings had overcome him, and Daniel had never liked nor admired him more than he did at that moment.

'The terrible truth is', Johnny's voice was husky as he went on, 'that if we allowed any of them to escape the cull, they would communicate their terror and panic to the other herds in the Park. There would be a swift breakdown in the elephants' social behaviour.'

'Isn't that a little far-fetched, Warden? Daniel asked softly.

'No. It has happened before. After the war there were ten thousand surplus elephant in the Wankie National Park. At that time, we knew very little about the techniques or effects of massive culling operations. We soon learned. Those first clumsy efforts of ours almost destroyed the entire social structure of the herds. By shooting the older animals, we wiped out their reservoir of experience and transferable wisdom. We disrupted their migratory patterns, the hierarchy and discipline within the herds, even their breeding habits. Almost as though they understood that the holocaust was upon them, the bulls began to cover the barely mature young cows before they were ready. Like the human female, the elephant cow is ripe for breeding at fifteen or sixteen years of age at the very earliest. Under the terrible stress of the culling the bulls in Wankie went to the cows when they were only ten or eleven years of age, still in puberty, and the calves born of these unions were stunted little runts.' Johnny shook his head. 'No, we have to take out the whole herd at one stroke.'

Almost with relief, he looked up at the sky. They both picked up the distant insect drone of an aircraft engine beyond the towering cumulus clouds.

'Here comes the spotter plane,' he said quietly, and reached for the microphone of the radio.

'Good morning, Sierra Mike. We have you visual due south of our position approximately four miles. I will give you yellow smoke.'