Our back garden now has a disputed border of blackbirds going down its centre, more or less following the line of the path. The males chase each other looking menacing, circling around a plant. The violence sometimes erupts into a head to head with the two leaping into the air, beak to beak, facing each other like the rampant supporters of a coat of arms.
I haven't seen our regular blackbird, White-tail, since January. Perhaps his absence has left a power vacuum and new blood is moving in.
Next door's hens have started to wander into our garden again, so I expect that 'our' garden will now become the territory of the cockerel and his hens.