If you see pigeons on power lines and there is a bridge or overpass nearby there's a pretty darn good chance that's where they are roosting. Wait until after dark and head in with a fish net and a flashlight. Don't shine the light directly on them.....SCOOP em up!!
Here is my question......describe if you don't mind how you are using these pigeons for training? Clip wings? Use and keep alive for later reuse? Kill/freeze/thaw use???