It is narrated from Sayyiduna Ibn Amr, may Allah be pleased with him, that the Noble Prophet, peace and blessings be upon him, said: "Whoever kills even a sparrow unjustly, Allah Almighty will question him about it on the Day of Resurrection."
Hadith Referenceمسند احمد / مسند المكثرين من الصحابة / 6550
Hadith Gradingحکم دارالسلام:إسناده ضعيف لجهالة صهيب مولي ابن عامر