Glen,
in contrast to birds, mutlicopters don't have any instinct of avoiding selfdistructive encounters with other aircraft.
And there are possibilities to predict at least the probability of a bird strike depending on the weather, the times and the surrounding environment. You can almost be sure, that multicopters don't adhere to these schemes.
And yes, they ARE (at least some of them) autonomous. The producers are advertising the ability of programming a path for them at home and then flying it without any further control inputs.
And they ARE (many of them) able to "return home" autonomously when battery starts getting low.
And especially helicopters (when firefighting, when doing MEDEVAC, EMS or any other low level airwork they're used for) are flying at or at least often at the same altitude levels.
The first mid-air is waiting to happen...
We pilots have to learn a bunch of rules, a load of procedures and payed a good part of a fortune only to be allowed using our airspace. And there are those owners of multicopters who bought them at some internet store for a few bucks, didn't have to learn anything, just plug a cam to those things and start flying in the same airspace without even knowing that there ARE rules that apply.
I don't want to propose to forbid multicopters, but the buyers at least have to learn a little bit about the rules that apply, the danger their toys may become for others and the consequences that may occur if something happens.
Thracian