Amazing concept!
I'm still not sure if I was steering them properly, but the gather/scatter controls feel finer.
One frustrating aspect is that if birds are far away from each other, "gather" fails to put them on the closest safe spot even if they all fit on screen, some will shoot across the screen to "try and join others" apparently.
Seems like the only valid strategy is to keep them all in a cluster, which I found less satisfying than "divide and conquer" approach.