RE: Pellets - Highly recommend the following: H&N Terminator and Predator Polymag. (Checkout
https://www.pyramydair.com/)
For birds, for some of them you'll need to make sure your point of aim tries to avoid going thru their wing feathers.
For example with Quail, it's astounding how much of a wallop some of them can take with a pellet if it hits the wing feathers. And definitely a Crows wing feathers are super tough. For better success, place the pellet at like the shoulder/neck junction just a little in front of where the wing doubles back when they have their wing folded in. Dove are significantly less of a problem regarding the wing feathers thwarting your shot.