Yes they are magpies and jays
Yes. Some of them.
Some birds eat grass but most eat seeds.
Some but not all. Some bats and birds both eat bugs.
Yes, some pet cats do eat birds and rabbits.
Some baby birds (robins) eat worms, but to some birds, worms are VERY toxic!
Some birds, like falcons, eat smaller birds, but large birds who aren't birds of prey don't
some birds eat peanuts
The goliath spider and the tarantula eats birds, but they eat small types of birds.
Some birds do eat their own feces for a second round of digestion, but this is only in a certain minority of birds (such as some owl species).
Yes, many birds of prey eat small mammals.
Some birds can eat bugs? and some eat seeds? and some eat meat?
Yes, some birds will catch and eat butterflies.