Pigeons seize the magpie's nest: turtledoves seize the magpie's nest. Metaphor occupies other people's residence or improper handling.
Pigeons occupy a magpie's nest: turtledoves don't build nests, but they often seize magpies' nests. Metaphor is to seize someone else's house.
Magpie laughs and pigeons dance: Magpies crow and pigeons fly. Used to be used as holiday information.