I remember I said about other macaws species but honestly I don't remember his reaction
I was a child then (10-13 y/o), so such answer would be too complicated for me

Normally I would explain only physical differences because that's what I was asked. But as a child I was just too shocked how somebody doesn't see any differences and the next question was "do budgies have waves and macaws not?" I answered "Yes but budgies not always have waves" (that's how we call their wings pattern) and it was enough

I had no energy to mention ino mutation
I met somebody who confused lovies and budgies too
Once time children called my budgie "canary"