Dont know what state your in but here its illegal to kill Doves with a airgun so you might look into that before you start shooting them..they are a federally protected bird except for the Eurasion Doves.
Myself I like .22 its plenty for Crows plus if you want you can extend your range over the .25 generally unless your into pcp airguns then I would use a .25.. Crow Mag pellets as said if accurate in your gun really smack critters hard.
