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Measuring the Effect of Unmanned Aerial Vehicles (UAVs) on Seabirds From Onboard and Ground-Based Video at Raine Island, Great Barrier Reef, Australia

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Thesis(2.79 MB)

Date

2023

Authors

Supervisor

Breen, Daniel
Hinchliffe, Graham
Zhang, Jingjing

Item type

Thesis

Degree name

Master of Science (Research)

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Publisher

Auckland University of Technology

Abstract

Conservation science requires innovative approaches to study wildlife without disturbing the species it seeks to preserve. Video and photogrammetry from unmanned aerial vehicles (UAVs or drones) can efficiently survey animals, vegetation and topography over large, difficult to access and sensitive environments. This information can be analysed in geographic information systems (GIS) to estimate changes in population size, density, distribution, diversity and behavior. Observing organisms and habitats from above can avoid the potential effects of trampling and a human presence in ground-based surveys and provide data from an alternate perspective. However, the drones themselves can have impacts, particularly for easily disturbed species like nesting and roosting seabirds. This study assesses the ability of drone based aerial video and still images to monitor seabird disturbance during surveys flown at 8 heights between 20 and 120m. The results are compared to estimates made from a ground-based video camera and to counts of birds leaving the ground made by three ground-based human observers. Still images sampled from the drone videos were orthorectified in ArcPro GIS and subsampled to count flying birds over the same areas of ground viewed from different heights. Three second videos preceding each still image assisted in distinguishing flying birds in each image from bird shadows and other artefacts. The counts of flying birds made from the drone videos and images were comparable to counts made by ground observers but recorded smaller numbers of flying birds, particularly at lower altitudes. The counts of flying birds made from the ground-based video camera provided a good overall view of flying birds, but estimates were confounded by resampling the same birds when the drone’s course directly approached the camera. The three survey methods each had advantages and biases and I make recommendations for conducting future research. For the ground-based observer and drone video methods, there was a general decrease in counts of flying birds when the drone was flown at greater heights. In these trials, only roosting birds took flight and most birds returned to the ground within a few minutes. The results suggest that, when necessary, flying a drone at least 60m above seabird colonies causes less disturbance. However, seabird responses to the drone varied greatly and there are other factors that require further investigation including the effects of type of drone and how it is flown, different seasons, population densities and species and the impact of less obvious physiological, feeding and reproductive effects on seabirds.

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http://hdl.handle.net/10292/16931

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