Well, I assume it’s not “abandoned”, as such, while it’s in operation so I wouldn’t think it’s free to claim. If it’s being flown recklessly I might try to capture it with the justification that it threatened the personal safety of myself and those around me. I do not know if that justification would fly (heh) and I’m pretty sure I’d be on the hook for proving it.

But that’s really all assuming; I’m not a lawyer, just a layman with an interest in logical systems.

Edit:

I should add that I generally think about the regulations for small drones (<.55 pounds and some other things) rather than the <55-pound ones because I have looked into flying one. I still think it’s maybe not the best idea to net a 30+ pound piece of flying machinery but the pilot certainly has more things to worry about.

Any delivery drone flying at 8 feet above the ground in your backyard is delivering to you, and would be probably implicitly considered to have your consent.

Actively trying to take it down would be in legal gray area, but you'd be probably in the clear if in court it was proven it was there intentionally and not in distress.

If it fell in "aircraft in distress" case you're fucked because it was operating legally.