The choke of a shotgun determines the spread or "pattern" of the shot at various ranges. If you shooting at close range such as quail, a wider choke is in order so the shot spreads more quickly. For waterfowl where you will be shooting heavier loads of shot at farther targets a tighter choke is needed.
I use number 8 shot and a modified choke when quail hunting.
I use number 2 shot and full choke for ducks/geese.
I use number 8 shot and an Improved Cylinder for early season dove(local birds) and number 6 shot with the full choke on late season dove(migratory, jet powered high fliers).
Now that I have said all that let me confuse the issue by saying that 10 different hunters might give 3 different shot choke combos for the same applications.