Aerial wildlife surveys have been used for many decades in Australia and abroad and are a useful, relatively quick tool for monitoring population size and distribution of wildlife. Despite the costs of running the aircraft, they are also a very cost-effective means of collecting data.
In Australia, aerial surveys have been used to look at deer, camels, donkeys, goats, horses, pigs, water buffalo, kangaroos, marine species, rock wallabies, waterbirds and malleefowl.
Aerial surveys typically involve flying predetermined transects. Increasingly, remotely powered aircraft (drones) are being employed in place of traditional manned aircraft.
A South Australia-based consultancy, EcoKnowledge, has recently conducted an aerial census of wild fallow deer in Tasmania using conventional aircraft (helicopter). The report on that is due out in mid-2020.
EcoKnowledge has also contributed to a research paper which was published in Wildlife Research in October, title Estimating kangaroo density by aerial survey: a comparison of thermal cameras with human observers. This is the first study to directly compare population data derived from thermal imaging with data collected by human observers during the same flight. This is of great interest to the Australian Deer Association because advances will make wildlife surveys more reliable and more affordable — ultimately enabling better management decisions.
The study had some interesting, but not surprising, results; the key points being:
Kangaroo density estimates obtained from the thermal camera data were about 30 per cent higher than human estimates.
The thermal survey was even more effective in wooded habitats.
The human survey was more effective in open habitats (possibly due to interference from sunlight and to animals flushing).
It was not possible to distinguish between species of macropods in the thermal imagery.
While it is clear that thermal survey techniques still need some refining, if researchers take their limitations into account they are already a useful and powerful survey tool.
It is entirely possible that conventional aerial survey techniques are underestimating animals in some habitats by a significant number.
As the technology evolves, and powerful computer algorithms for assessing the data are developed and refined, thermal cameras will almost certainly revolutionise wildlife surveys as a management tool.
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