PETER THEOBALD says:
You will soon see if shooting at flighting pigeons a distance away from their roost is having any effect on them landing, by watching the reactions of birds you have just fired at.
If they just carry on into the wood and continue to land, you have cracked it.
Smaller woods are likely to be affected more than large ones, but for it to work at all, you need a decent wind, the stronger the better, and preferably for it to be blowing from the wood.
The stronger the wind, the closer you will be able to get to the wood without disturbing it.
If the wind is blowing towards the wood, you will certainly need to be half a mile away, quite apart from the fact that pigeons seldom approach their roosting wood downwind.