I'm sure you understand that the birds feasting on the berries had nothing to do with the problems the shrubs are having now.* These guides should help you narrow down what is going on.
I always recommend using organic methods and natural control products first.*
Let me know what seems to fit.
When weeding, the best way to make sure you are removing a weed and not a valuable plant is to pull on it. If it comes out of the ground easily, it is a valuable plant.