#6 is what I would use. I typically hunt quail and chukar with #7 1/2

Federal Premium copper coated 6's. they'll drop!

at this time of year,usually shots at grouse here in pa. are long.

so, i use low brass no. 7 and 1/2 as first shot and high brass no. 6 for second.
no need for 3 rd shot so i only load 2 shells..

i also use mod or imp.mod in my 12 ga.

you can use full choke and get away with just using 7 and 1/2 shot low brass and skip high brass but you must be a good shoot.........

We hunt wild birds in Mn., Ia., N & S Dakota and high base 5's or 6's is the shot of choice, using 4's on windy winter days.