It is narrated from Sayyiduna Zayd bin Khalid (may Allah be pleased with him) that a man came to the Prophet (peace and blessings be upon him) and asked about lost property. He (peace and blessings be upon him) said: "Announce it for a year, then know its pouch and its tie and remember it. If its owner comes, give it to him; otherwise include it in your spending and make use of it." He asked about a stray sheep. He (peace and blessings be upon him) said: "It is for you, or for your brother, or for the wolf." He asked about a stray camel, and the face of the Prophet (peace and blessings be upon him) turned red. He (peace and blessings be upon him) said: "What do you have to do with it? It has its shoes and its water-skin with it; it can drink water and eat the leaves of trees. Leave it until its owner finds it."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب اللقطة / 12085