I've seen quite a lot of bird nearmisses, as a tower controller, and quite a few strikes. (And in one case a bird death apparently resulting from a loss of control/ground impact after a wake turbulence encounter. Oyster catcher vs B732.)
Different species of bird definitely exhibit different behaviour when an airliner is about to share their airspace, ranging from apparent oblivion, through random scattering, to an intelligent appearing and timely avoiding manoeuver. That last is rare. Usually the bird avoiding action, once it has perceived the aeroplane, occurs as or after the aeroplane passes.
I haven't particularly noticed if flocking makes a difference, although it appears that some birds flock together in a cohesive avoiding action (Starlings and pigeons, for example), others randomly scatter and others seem to become agitated, yet seem stoically to refuse (or unable) to break formation, like Canadian geese.
This would make an interesting study, for sure. (Is anyone doing it?)
I know from experience (mentioned several posts back) that some types of birds will immediately turn, together, if the aircraft heading toward them starts a turn the other way. It doesn't need to be a 60 degree bank. They start turning as soon as they register the bank...maybe 5 degrees, if that. And in one story above, concerning the Buzzard, the bird turned with the aircraft. Twice. (The dumbass.)