Musnad Ahmad 25:1066

Hashim narrated to us, Abu Mu'awiyah—meaning Shayban—narrated to us, from Layth, from 'Abd al-Malik, from 'Ikrimah, from Ibn 'Abbas, who said: The Messenger of Allah (peace and blessings of Allah be upon him) used to be optimistic and did not practice *tatayyur* (taking omens from birds or bad luck). He liked every good name.