Hadith 4884
عَن أنس قَالَ: إِنْ كَانَ النَّبِيُّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ لَيُخَالِطُنَا حَتَّى يَقُولَ لِأَخٍ لِي صَغِيرٍ: «يَا أَبَا عُمَيْرٍ مَا فَعَلَ النُّغَيْرُ؟» كَانَ لَهُ نُغَيْرٌ يَلْعَبُ بِهِ فَمَاتَ. مُتَّفَقٌ عَلَيْهِ
Anas (may Allah be pleased with him) narrates that the Prophet (peace and blessings of Allah be upon him) did not act formally with us (he lived among us informally), to the extent that he would say to my younger brother: "Abu Umair! What did the little bird do?" Abu Umair had a small bird with which he used to play, and it died. Agreed upon.