Sayyiduna Ibn Abbas (may Allah be pleased with them both) said: At Kura' al-Ghamim, the leg of a wild donkey was given as a gift to the Messenger of Allah (peace and blessings be upon him). He (peace and blessings be upon him) returned it to the one who gave it and, apologising, said: "We are in a state of ihram."
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 10948