#7 steel is terrible on duck and pheasant, you'll wound more than you cleanly kill unless they're inside 15-20yds.
#7 steel will not reliably penetrate all the way thru a quail lengthwise.Quail is the largest bird i'd hunt with #7 steel, doves are good with #7 steel.
Pheasant/duck..#4 steel is the smallest you should use, #5 steel works on close decoying ducks.#3's are best for pheasant/duck.