Mufti Muhammad Taqi Uthmani (Daamat Barakaatuh) writes:
In the time of Hadhrat Umar (Radiyallahu Anhu), Hadhrat Amr ibn ‘Aas (Radiyallahu Anhu) was sent to conquer Egypt by Hazrat Umar (Radiyallahu Anhu). The army reached the city of Cairo and laid siege on it which lasted for approximately six months. Hazrat Amr ibn ‘Aas (Radiyallahu Anhu) erected a large tent in front of the city. When it was time to dismantle the tent, Hazrat Amr ibn ‘Aas (Radiyallahu Anhu) saw that a pigeon had laid an egg on top of the tent. He feared that if the army dismantled the tent, then in the process the pigeon egg could break. Not wishing to cause the least amount of pain to this creation of Allah Ta’ala (i.e. the pigeon), Hadhrat Amr ibn ‘Aas (Radiyallahu Anhu) commanded that the tent remain as is until the egg hatches and the chick is able to fly. Thus, the tent remained in that condition until the egg hatched and the baby bird was able to fly. (Jawaahir Paare)