Table 4. Disturbance effects on mixed flocks of waterfowl for UAVs launched from different take-off sites and flown at various approach angles.

UAVs were flown either directly perpendicular to a sitting flock of birds or in a tangential flight path running parallel to the main flock of birds. Survey location involved birds at either a large (Llangothlin) or small (Cargelligo) water body.

Location	UAV	No. of flights	Take-off location/direction	Angle of approach	Disturbance effects
Little Llangothlin Lagoon	Avian-P	2	close to shore/away from lake	Perpendicular to flock	Birds flew away from shore on take-off, no disturbance during flight
Little Llangothlin Lagoon	Avian-P	2	close to shore/away from lake	Parallel to flock	Birds swam away from shore on take-off. Birds flew during rapid descent to from 80 m to 60 m
Little Llangothlin Lagoon	Topodrone-100	2	700 m away from shore, out of sight/Towards lake	Parallel to flock	No Disturbance at altitudes above 60 m
Little Llangothlin Lagoon	Topodrone-100	2	700 m away from shore, out of sight/Towards lake	Perpendicular to flock	Birds flew away from shore on approach at 80 m but became acclimatised to the UAV. Birds flew when the UAV banked and dropped to 60 m.
Little Llangothlin Lagoon	Phantom	2	close to shore/vertical take-off	Perpendicular to flock	Birds were vigilant and swam slowly away from the UAV
Little Llangothlin Lagoon	Skylark II	2	close to shore/ directly at flock of birds	Parallel to flock	Birds flew away on take-off, and with banking at 60 m
Little Llangothlin Lagoon	Skylark II	2	700 m away from shore, out of sight/Towards lake	Perpendicular to flock	No disturbance
Lake Cargelligo Sewage Works	Skylark II	2	100 m away from shore out of line of sight/away from water	Parallel to flock	No disturbance at any altitude
Lake Cargelligo Sewage Works	Kraken-130	2	100 m away from shore out of sight/vertical take-off	Parallel to flock	Birds were vigilant and looked up at the UAV at altitudes below 60 m but did not move from their roost.