Sayyidah Umm Kurz al-Ka'biyyah (may Allah be pleased with her) narrates from the Prophet (peace and blessings be upon him): "For a boy two sheep and for a girl one sheep are to be slaughtered in the aqiqah; it does not matter whether they are male or female." And I heard him (peace and blessings be upon him) say: "Leave the birds in their places."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الضحايا / 19336
Umm Kurz al-Ka'biyyah (may Allah be pleased with her) said that the Messenger of Allah (peace and blessings be upon him) said: "Leave the birds in their places." And someone other than him narrated from Sufyan: "Leave them in their nests."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الضحايا / 19337
Ibrahim bin Mahmud (may Allah have mercy on him) said: Someone asked Yunus bin Abd al-A'la (may Allah have mercy on him) what is meant by the saying of the Prophet (peace and blessings be upon him): "Leave the birds in their places." He said: Allah loves the truth. Imam al-Shafi'i (may Allah have mercy on him) explained it as follows: In the Jahiliyyah, when a person had some task to do, he would make the birds fly from their nests. If a bird flew to the right, he would go ahead with his task, and if it flew to the left, he would refrain from it. So the Messenger of Allah (peace and blessings be upon him) forbade this.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الضحايا / 19338