Musnad Ahmad 145:1

Uthman ibn Umar narrated to us, Abd al-Hamid and Muhammad ibn Bakr narrated to us, they said: Abd al-Hamid ibn Ja'far informed us, my father narrated to me, from Tamim ibn Mahmud, from Abd al-Rahman ibn Shibl: "That the Messenger of Allah (peace and blessings of Allah be upon him) forbade three things: the pecking of the crow, the spreading of the beast of prey, and that a man should designate a specific place in the mosque—Uthman said—just as a camel designates its place."