Another country boy pilot who made a similar observation was P47 Thunderbolt ace Robert S. Johnson. He hailed from Oklahoma and I seem to recall his mentioning in his memoir that bird hunting had helped his shooting enemy planes tremendously. Wish it helped me. I got two shots yesterday on the last day of duck season and missed both...
I have never been bird hunting but those that I know who have say if you can hit a grouse, you can shoot anything.