The use of Remotely Piloted Aerial Systems (RPAS) for wildlife monitoring

There are many methods to estimate wild ungulate populations. One of these is represented by observations from vantage points usually employed in medium-low covered forest areas to estimate cervids. This method is subject to some limitations, such as the risk of double counting and the necessity to a high number of operators due to the small size of the observable areas. Such limitations could be reduced by integrating the “vantage points method” with Remote Piloted Aircraft System (R.P.A.S.) surveys. This study reports some experiences carried out mainly to check the suitability of R.P.A.S. use in the specific case of Roe deer (Capreolus capreolus) and Wild boar (Sus scrofa). The investigation was conducted in various areas with a high density of Roe deer and in the absence of disturbing elements. The first experimental phase concerned the definition of technical parameters useful to characterize the research system. For this purpose, the acoustic emission of the aircraft (dB) and shots of the underlying ground were recorded at intervals of 10 m up to 70 m above the ground. In the second phase, operating flights were carried out on an area of around 90,000 m2 consisting of seven contiguous grazing areas separated by hedges and woody plants. The ability to fly over the natural visual barriers (land orography, trees, hedges, etc.) allowed to conduct a census over all the study area, despite its size and its characteristics. Only two operators can do all the flights in an average time of about 10-15 minutes with a R.P.A.S. speed of approximately 3 m· s-1. The analysis of the aerial pics taken at dusk from 50 to 60 meters has identified many Roe deer grazing in different areas and has verified the absence of any animal alarm reactions to the passage of the aircraft. As for Wild boar, animal species with more pronounced nocturnal activity, the tests were conducted using a thermal imaging camera installed on board the R.P.A.S.