Musnad Ahmad 30:1946

Aswad ibn Amir narrated to us, he said: Hammad narrated to us, from Abu al-Muhazzam, from Abu Hurairah, he said: The Messenger of Allah (peace and blessings of Allah be upon him) said: "The people of Medina shall surely leave Medina, while it is at its best, fertile and abundant in produce." It was said: "Then who will eat it?" He said: "The birds and the beasts of prey."