I think AB makes a good point about the general advisability of treating working birds like a plane with regard to wind direction and giving them room to work and break down well out.
Fwiw, here's my take on working birds from the perspective of momentum as written for another board some years ago:
At its tactical core, calling ducks is about momentum: creating it, breaking it, maintaining it and, sometimes, just not getting in its way. So I take my calling cues by paying attention to the birds' momentum.
If the location and decoys are doing my job for me, and the birds want to come to the guns, I'll let 'em. Calling only enough to keep them coming if they waver and/or to put them "right there". Not getting in the way of birds that want to work was little doubt the inspiration for the old saw about calling only to tail feathers and wing tips.
By the same token, if the birds haven't shown me their intent, I'll call just enough to get our hat in the ring. And if they jump for it, chances are they can be finessed the rest of the way by tickling them "on the corners". Again letting the birds' momentum do most of the work.
But if birds blow off a simple greeting and drive on toward parts unknown, I've got nothing to lose and everything to gain by hitting them hard with the call. Here again, if they're quick to turn to it, they'll probably do most of the work from there on in.
And if they don't turn to, I really amp it up, watching for any little wink or blink of a wing suggesting the jackhammer will work if I can just crank it up a little louder and longer. When I can't get anything to flirt, I'm only out some wind. But when something will wink or blink, and I don't run out of wind, our chances of getting shooting out of it are excellent.
Wasn't always so, however, because when I'd worked that hard to break something off a flock or turn the bunch, I worried about over calling and backed off as they headed to us - only to lose them when I did. Took me a lot more such losses than I'm happy admitting to realize that even when I turned the whole flock and not just a bird or two from it, the real momentum was still headed toward whatever was drawing them away in the first place and might well stay that way. Many such birds are either coaxed all the way to the guns or lost, presumably to their prior destination.
If there's a "rule" to such things, it may be that the harder birds are to turn in the first place, the more likely the need to call to their faces until you call the shot. "Tails and tips" be damned.
Very often, too, we'll see that birds within hailing range appear deaf, because they're zeroed in on another nearby spot, and our best efforts aren't turning them. We can't break the momentum toward that location within their view, like we could toward a distant, perhaps less tangible, goal.
But it's often the case that we can then use their own momentum against such birds by letting those apparently locked on such a spot go to it, break down for it, and then, when their circling heads them our general direction, calling to their faces to keep them headed our way, perhaps thinking there might be a better deal just a little farther on. Or just caught up in the call.
Again, though, don't let up as they approach or pass a good shot hoping for a better one, because they've already shown that what they really want is over yonder.
And that's more than enough of that for a while. Lots and lots of other tactical stuff, including gosh knows how many under the label "most important thing" or "secrets" that probably aren't. But I think a fellow who really pays attention to momentum and calls accordingly has a far better foundation to build on than most.
If you think I'm wrong, you might be right.