It is narrated from Abdullah bin Umar (may Allah be pleased with them) that the Messenger of Allah (peace be upon him) said: "There are five animals which it is not sinful for a person in the state of Ihram to kill: the crow, the kite, the scorpion, the mouse, and the biting dog."
Hadith Referenceمسند الإمام الشافعي / كتاب الحج / 910
Hadith Takhrijأخرجه البخاري، جزاء الصيد، باب ما يقتل المحرم من الدواب (1826)، (3315) ومسلم، الحج، باب ما يندب للمحرم وغيره قتله من الدواب في الحل والحرم (1199)۔
It is narrated from Ibn Abi Ammar: He said, I saw Ibn Umar (may Allah be pleased with them) at the place of Baida, in the state of Ihram, shooting a crow with an arrow.
Hadith Referenceمسند الإمام الشافعي / كتاب الحج / 911
Hadith Takhrijإسناده صحيح: أخرجه البيهقي في المعرفة السنن والآثار (3235) وعبد الرزاق (8383). وابن أبي شيبة (15735)۔
It is narrated from Rabi'ah bin Abdullah bin Hudair that he saw Umar bin Khattab (may Allah be pleased with him) at the place of Suqya, in the state of Ihram, removing ticks from his camel and throwing them into the dust.
Hadith Referenceمسند الإمام الشافعي / كتاب الحج / 912
Hadith Takhrijإسناده صحيح أخرجه البيهقي: 5 / 212 - وفي المعرفة السنن والآثار له (3240)۔ وعبد الرزاق (8409)۔ وابن أبي شيبة (15274) - ومالك في الموطأ، الحج، باب ما يجوز للمحرم أن يفعله۔
Maimun bin Mehran narrated that I was with Ibn Abbas (may Allah be pleased with them) when a man asked him: "I caught a louse and dropped it, then searched for it but could not find it." Ibn Abbas (may Allah be pleased with them) replied: "This is a lost thing for which there is no need to search."
Hadith Referenceمسند الإمام الشافعي / كتاب الحج / 913
It is narrated from Maymun bin Mehran, he said: I was sitting with Ibn Abbas (may Allah be pleased with them) when a man came and sat down. I had not seen a man with longer hair than him. He said: I have entered into Ihram while having this hair. Ibn Abbas (may Allah be pleased with him) said: Tie up the hair above your ears. The man then said: I kissed a woman other than my wife. Ibn Abbas (may Allah be pleased with him) said: "Your mouth has committed adultery." The man then said: I saw a louse and threw it away. Ibn Abbas (may Allah be pleased with him) said: "This is such a lost thing that there is no benefit in searching for it."
Hadith Referenceمسند الإمام الشافعي / كتاب الحج / 914
Hadith Takhrijإسناده صحيح: أخرجه البيهقي 5 / 213 - وفي المعرفة السنن والآثار له (3243)۔