Unless you have some real ass on a .177, don't use it. It's cruel. Use a .22 pellet rifle (or better) and use pellets. Likewise, make sure it has some ass behind it too. As you rightly point out, they will associate the person who is killing/attacking them. They can retaliate. This can include shitting all over the place, attack you when you exit your house, calling in others to do the same, or even steal and pilfer stuff from around your house. They can be very cool birds or super assholes.