Blue jays are so aggressive towards the other birds that come to feed at my kitchen window. We get cardinals, titmouse, chickadee, robins, and others. The blue jays are triple their size and don't care for the competition.
Jackdaws in the UK do it as well, but they definitely hang around like little gangs of urchins on people’s verges and front lawns; humans amuse them.
(They also grieve, despite what people say; I saw our local gang of six once, reduced to five, making odd quiet noises and unwilling to leave one of their gang that had been struck by a car and was quite obviously dead).
Now excuse me while I pack my box with five dozen liquor jugs.
Who doesn’t want to see something amazing like a parakeet in a random British back garden? All the other birds, that’s who!