Pliny the Elder [1st century CE] (Natural History, Book 10, 74): Thrushes build their nests of mud in an almost continuous mass on the tops of trees, and breed in retirement. The eggs grow to full size in the uterus in ten days from pairing - [Rackham translation]

Isidore of Seville [7th century CE] (Etymologies, Book 12, 7:): The thrush [turdus] is named from its tardiness [tarditas], for at the very beginning of winter it returns. The turdela is a larger thrush, as it were. It is thought to produce mistletoe by means of its droppings. - [Barney, Lewis, et. al. translation]

Thomas of Cantimpré [circa 1200-1272 CE] (Liber de natura rerum, Birds 5.115): Thrushes are birds, as Pliny says, of small body indeed, but of great foresight: for, building nests in the tops of trees with mud almost woven together, that is to say continuously, they breed in seclusion from copulation, and it is surprising that ten days after copulation the eggs ripen in the womb and then give birth. ... Indeed, these birds signify those who, capable of all good, having conceived in the heart a good purpose, immediately put their hands to its accomplishment, and bring back salutary fruits. - [Badke translation/paraphrase]