Musnad Ahmad 456:22

Sufyan narrated to us, from Yahya ibn Sa'id, from Yazid, the freed slave of al-Munba'ith. Yahya said: Rabi'ah informed me that he said, from Zayd ibn Khalid. I asked Rabi'ah, and he said: He informed me from Zayd ibn Khalid: The Prophet, peace and blessings of Allah be upon him, was asked about a stray camel. He became angry, and his cheeks turned red, and he said: "What do you have to do with it? It has its footwear and its water skin; it reaches the water and eats the trees until its owner comes to it." He was asked about a stray sheep, and he said: "Take it, for it is either for you, or for your brother, or for the wolf." He was asked about lost property (luqatah), and he said: "Identify its container and its tie, then announce it for a year. If its owner is identified, [give it to him]; otherwise, mix it with your wealth."