Sources : Starling
Pliny the Elder [1st century CE] (Natural History, Book 10, 35): ...starlings also migrate in a similar way to neighboring districts; but these do not moult their plumage, and do not go into hiding, being often seen in the places where they forage for winter food. It is a peculiarity of the starling kind that they fly in flocks and wheel round in a sort of circular ball, all making towards the centre of the flock. - [Rackham translation]
Thomas of Cantimpré [circa 1200-1272 CE] (Liber de natura rerum, Birds 5.113): Starlings are small birds, as Pliny says, and they are always ready to fly. They are dark in color. They fly in a group in a kind of ball, all tending towards the middle, and this because of the hawks who lie in wait for them. They gather together in the evening in immense, murmuring crowds. Liber rerum: Silent at night, the red dawn stirs them to a murmur; finally, they fly in groups for food. - [Badke translation/paraphrase]