251.Whoever kills a sparrow or anything bigger than that without a just cause, Allah will hold him accountable on the Day of Judgement. The listeners asked, O Messenger of Allah, what is a just cause? He replied, That he will kill it to eat, not simply to chop off its head and then throw it away.
(Nisai, Hakim).
(The Lawful and Prohibited in Islam (arb: Al Halal Wal Haram Fil Islam) by. Yusuf Qaradawi).