02 Dec Annual Aerial Census
The Welgevonden Game Reserve Annual Aerial Census was conducted over three days during September 2011.
The count is done using a helicopter with a pilot and data capturer in the front two seats and an observer on each side in the rear two seats.
The pilot and data capturer also act as observers, especially to observe below the helicopter. On Welgevonden we fly with the doors off for better visibility and endure the cold with flight suits, beanies, gloves and goggles. The googles used have a yellow tint which helps improve visibility.
The Reserve is divided into three sections, and counted over a period of three days by flying east/west transects of 400m. Therefore, 200 m on each side of the helicopter are counted with each flight line. In this manner, the census is conducted over the entire Reserve.. The cut-line at the end of each day is either a road, in a valley or on top of a ridge in areas where it is unlikely that large numbers of animals will cross during the night. The size of the Reserve forces us to make this compromise even though it may introduce negligible error. .
During the flight the counters call the species and numbers to the data capturer via a headset and microphone, who feeds it into a laptop computer. The GPS reading is also automatically taken with each entry and plotted onto a map. With this method results and distribution maps are immediately available and the helicopter flight line is also mapped.
When animals that are difficult to see (eg. kudu ) or large herds of animals (eg. impala) are observed, the animals are circled to make sure all are counted and that there are not some animals hiding in the bush where they were not immediately visible.
Each day consists of about three sessions of 1½ to 2 hours each. Between each session, a break of more or less 45 minutes is taken to refuel the helicopter and to give the counters a time to rest and get something to eat and drink. The first sessions start at about 7am, and normally the last session finishes between 2-3 pm.
The principle of any aerial game count is not necessarily to count every individual animal on the property, which is nearly impossible except on a relatively small area, but to have a consistent count over a number of years in order to determine the trends in a population. The simplified principle being that the error in counting needs to remain constant during each count which will then give a person an idea of a trend within the population of each species.
For the counters the rare and charismatic species are often a highlight to be seen from the air. Animals such as serval, caracal, leopard, python, brown hyeana, aardvark, lion, ratel or honey badger, etc. have been observed.
Other observations of alien plants, erosion sites, potentially problematic sewerage systems, old farm rubble and wire, exposed water pipes and power cables are also GPS recorded for attention later.
The figures of the animals counted over the last four years are given in the table below corrections have been made for known numbers and introductions close to the census. Please note that the lion numbers are managed, the elephant population is contracepted, a leopard study has been undertaken and we have known individuals using the Reserve, additional buffalo have been introduced as well as impala, wildebeest and zebra.
Welgevonden Game Reserve Annual Aerial Census Results: