 307 Squadron was named after the Polish city of Lwów, and was nicknamed "Eagle Owls".The nickname "Lwowskie Puchacze" (NOM) – "Lwów Eagle Owls" was chosen for the night fighter squadron, as the eagle owl is a nighttime avian predator that is present in Poland.The Squadron inherited the traditions of the Polish pre-war 6th Aviation Regiment, that was stationed in Lwów (now Lviv), with a history dating back to the defence of Lwów and Galicia from invading Ukrainian forces in the Polish-Ukrainian War of 1918–1919.