Author: Joe Holmes
Aerial surveys of wildlife areas are faced with several criteria that impact them.
In the main, these are cost and accuracy. The available budget determines the aircraft type to be used and how much flying time this will allow. In turn, the aircraft type selected has a massive impact on the accuracy of the collected data, and its consequent validity. Microlight Trikes are extremely well-suited for conservation work, as they are affordable and more ideally suited for observational work than any other. This type has completed hundreds of early Bateleur missions.
Maputo Elephant Reserve Bateleurs Mission
The management and research component of the Maputo Elephant Reserve needed to do a follow-up count, but could not afford the helicopter they wanted. The Bateleurs were approached and it was agreed that we would provide microlight Trikes as the aircraft of choice for this census.
In a typical aerial census, the helicopter would fly approximately 500’ above ground level, at an economical cruise speed of around 160kph, flying a transect of 1km separation. This translates into following a series of imaginary lines across the terrain one kilometre apart. The spotters seated in the chopper consequently can and do miss lots of animals, due to bush cover and a major issue is that elephants do not like the noise made by helicopters, as they hold a lot of negative associations with this type of aircraft. Microlights by comparison are vastly quieter and not having been used for darting or other capture work, the elephants do not take exception nearly as much, to the Trikes arriving overhead.
Elephants move quickly
The next major issue is that elephants can and do move quite quickly, and thus a herd could conceivably be missed completely or counted twice. They also operate as herds and are not conveniently scattered evenly across a park, allowing for probable extrapolation of numbers.
Enter the multi-microlight squadron format. This is how it works: In the case of Maputo Elephant Reserve the area to be counted was 30km long and 25 km wide.
Aircraft formation
Two formations of 5 aircraft were used to count, flying in the following formation. 400 metres between planes at an altitude of 300’ above ground, and an airspeed of 75kph. This gave an effective ground coverage of 100% for a 1, 5 km wide belt, significantly better than a helicopter. To ensure tight control of accuracy, each microlight had its own dedicated GPS route programmed into its Nav GPS. Pilots zoomed in on the track detail, to achieve no more than a 20m weave off the track, which is very accurate.
Then the cherry on top from the researcher's perspective, was that we put them into a much faster “chase plane”, following the census formation. In the back seat, the researcher sat armed with a camera and telephoto lens, to enable individual photos of all the elephants seen. With all planes being in constant radio contact it is simple to direct the chase plane to the appropriate side of the formation to begin their photography. Elephants have a lot of unique features, allowing them to be individually recognised. This information is invaluable for later study purposes, to ID herd movement, behavioural tendencies and herd composition.
Now having two formations of aircraft we began the census of both the western and eastern boundaries, and the flights moved inexorably inwards until they met in the middle. This reduced the likelihood of any herds being able to go unseen.
Aircraft comparison
By comparison to the helicopter census, the microlight version counted 150 elephants as opposed to the chopper seeing 70. In addition, every animal was captured on film.
The downside of the microlight format is having to recruit and coordinate sufficient volunteers and sort out the significant logistics of getting them all on-site at the appropriate time. Nonetheless, with the planning done, using microlight Trikes proved to be a highly successful method.
