I read an excellent study on flying around birds and how not to bother them. Seems they are bothered a lot more from angle of approach, I've found this true. Trying to avoid flying directly overheard and using an appropriate approach angle seems to make a big difference in leaving them undisturbed.
Here's the study if you haven't seen already:
Approaching birds with drones: first experiments and ethical guidelines
Here's the study if you haven't seen already:
Approaching birds with drones: first experiments and ethical guidelines