Al-Sha'bi (may Allah have mercy on him) narrates from the Prophet (peace and blessings be upon him) in marfu' form that he (peace and blessings be upon him) said: "Whoever leaves an animal in a place of destruction, and then a man revives it, it belongs to the one who revived it."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب اللقطة / 12114