Here's three I've taken birds with that maybe new to the list. I live close to New York state and have hunted turkeys there since the 80s. I also hunted alot of grouse with bird dogs in the fall and trained them to behave after. Belgium Browning superlight 20ga O/U improved/mod 3", Rosi side by side 20ga improved/modified 3", Remington 1100 20ga 2 3/4", all with no sixs.
Oh yeah bonus gun, killed spring gobbler back in 1968 with 16 guage knickerbacher sided by side. Who knows what the chokes were, we didn't even wear camoflage then except for head net(some of us) and I was considered an innovator when I used a black garabage bag to keep my butt dry. I also tried a cople of 10ga that weighed a few back then.
Today I use 870s in 20 or 12 and occasionally my 1100 that I used for most of the years in between. 3" shells 5s backed by 6s.