Certainly not, if there’s any chance of endangered species visiting your berry patch

I agree here. What if the bird population wasn’t endangered and considered a pest?

To be clear this is hypothetical. I haven’t done anything.

You can’t guarantee that only “pest” birds (which still may be native, protected species) will visit your feeder, or that they won’t carry some illness or parasite to pass on to your cat.

I’ll counter with. I have a vet. I am interested in birdwatching and the cats are only outside supervised.

Good points.

Ask your vet if they think it’s a good idea to let your cat eat random wild birds during an outbreak of H5N1 ¯\_(ツ)_/¯

I like bird watching too, and it’s easier to do without a predator scaring them off.