Probably not, but HSS starts generating light before the shutter starts to move. Comparable to the preflash me thinks - enough time for the bird to react.
So, you'ld have to be a bit lucky. I would suggest to take an educated guess on where the bird is most likely to be settling and set things up accordingly. Agreed, one would miss quite often but sometimes you'ld nail it. I really don't see an alternative if automatic preflash is not an option. Perhaps an old TTL flash might do a better job since it doesn't generate a preflash (but you'ld have to find a way to fool the flash sensor to sense how much light is generated). Hey - this is actually a good idea to dust of the old analog camera . Without kidding, perhaps an older automatic flash that runs in standalone mode is the solution? There are Metz flashguns out there that read the reflected light and cuts of the light when done without camera intervention... that might work.Now, to doing it with manual flash settings. Here is a challenge! There is no way you could ever calculate the correct settings and make the adjustments in the very brief time you have
If it allows 3 times the reach, that thing would be pretty efficient (3 x reach = 8 x the light!). I don't own a BB, but googling brings up values varying from 1 to 3 stops - and that is quite astonishing in my book.The Better Beamer isn't terribly efficient; it's a fiddly damn thing to set up and you still spray a lot of light around where you don't need it, but is does make quite a difference to your reach. Wild guess: 3 x more reach?