If the birds are roaming freely then they are either; feral birds and a public nuisance which should mean that state wildlife officers do not care if you kill them or they do belong to someone then that person is guilty of failure to contain and control his animals.
Either way I can certainly sympathize with the person who has been shooting these birds.
I work a rotating shift and I cannot imagine trying to sleep during the day with those obnoxious birds screeching outside my house.
Screeching, damaging auto paint with claws and feces...