A friend recently sold a Parker #3 frame 12 gauge with no safety. I'd say that was definitely a fowling piece and not a pigeon gun. I agree. Lack of a safety is not definitive of a pigeon gun, a pointer only.
I'm not saying live pigeons were never shot with 20 gauge guns. I'm sure it happened and happened often back in the day. Ladies, young shooters, and men that liked a 20 bore probably did it. I'm saying that they weren't used in serious competition amongst men who shot pigeons as a near religion back in the day or now either one. I argee. If you look at the above published information, you see there was almost for sure a need for smaller guns for smaller people. No offense intended before, just trying to illustrate this point. If I were serious, I'd not go to the ring with a 20 bore. If having expensive fun, well, one shoots what makes one smile.
I've read of some sparrow shooting matches here in the US as well. The ring owner down in Indiana used to do a starling match every year though I never did get to shoot in it. He'd cannon net them on a big horse farm where they gathered in huge flocks to feed on waste grain. When I was in Texas, we had a straling "gathering" problem. It would take about 80# dead on the ground to convince them to move along.
Destry
