‘Good to go!’ said the email’s subject line. And so, just two mornings later -- three days before the end of June -- we were going, speeding down the airstrip in a small two-seater plane. After eight months of scheming and planning, plus a thousand emails, the 2014 national survey of the African elephant in Zimbabwe was starting.
As the plane lifted off and banked, Makuti lay to the left. This small place -- far too small to be called a town -- marks a T junction in the tar road: north to Chirundu and Zambia, or west to Lake Kariba. Its only petrol station had closed three weeks earlier. As the plane headed south, Makuti -- located on high ground amongst the hills of the Zambezi escarpment in northern Zimbabwe -- was most noticeable for its mobile phone towers and very tall radio masts (‘jammers’ someone had said). Such structures are a relatively new hazard to low-flying aircraft during elephant surveys – phone towers did not exist when I first flew wildlife surveys in Zimbabwe.
Most aerial surveys of elephants involve flying long, straight flight lines at low-level. But that was not safe in this hilly terrain. Here we used a different approach. First, on a map, the area was divided into blocks, defined using rivers, vehicle tracks, or watersheds as boundaries. Then we selected at random some of the blocks and these were ones that we now searched for elephants.
A few days later, I handed over the role of recorder/observer to Greg. I had to return to town and organise logistics for the next stages of the programme: surveys of the elephants in Gonarezhou NP in the southeast lowveld and over the floor of the Zambezi Valley, just north of the hills that we were flying now.
Once back in town, I wanted to buy more drums to transport avgas to the remote airstrips that the aircraft will use during the surveys. New, lined drums reduce the risks of fuel being contaminated. Economists may regard globalization as a good thing, but the disadvantages are immediately clear to me: there is a workers’ strike at the South African factory that makes the sheet metal which the Zimbabwean company imports to manufacture new drums. Hence, no new drums are available and no one knows when they will be. We will have to come up with another plan for fuel. And I need to import those fancy filters to make doubly-sure that no contaminated avgas goes into the plane.
It is now the beginning of August and the survey programme has moved to Gonarezhou. Here we will fly those long straight transects. But first we must calibrate the width of the search strips. We fly backwards and forwards across the airstrip, with metre-high numbers, ten metres apart, aligned along the edge of the strip. For each pass over the strip, I note the aircraft’s height above the ground from the radar altimeter. Radar altimeters are essential for transect surveys (we can calculate the width of the search strips only if we know the aircraft’s height above the ground). But they are also notorious amongst survey biologists for being expensive and temperamental. And so it proves today. We need to adjust the rods attached to the wing struts to demarcate those search strips. We land and taxi towards the hangar and the spanners. Suddenly the altimeter display goes blank. No amount of fiddling with fuses returns it to life. Very soon, the sun sets and we head back to camp.
In the middle of the night, some elephant bulls wander through camp, weaving round the tents. In the past, Gonarezhou’s elephants had a reputation for being aggressive, but no more. We assumed that these bulls were the same ones that approached camp earlier during the day. They had walked past Fay as she stood on the edge of camp, phone to ear, searching for a better mobile signal.
The next morning, more fuse-fiddling and even a test flight failed to return life to the altimeter. We consulted Olivia, ZimPark’s chief ecologist (easy to do, she was staying in the next-door tent). We rescheduled the survey for October. For me, it is back to town again. We need a substitute for that radar altimeter – we need a laser rangefinder. Once we obtain one, we will need to commission a custom bracket to attach it to a wing strut. And of course there will have to be a test flight. All within the two weeks before the start of the next survey – two weeks which would be divided by a four-day holiday weekend.
- Kevin from the Zimbabwe survey team