I use digital video through a 120 degree webcam facing due north. i use ufo id and have been observing the sky for months. i did not witness the occurrence. this is the only occurrence i have been able to video tape to date. days that followed no objects were observed. in attached videos numerous opaque circles are observed flying straight, in circles reversing course extremely fast. the weather during that time clear skies with infinite visibility, temperature 28 c. there were no birds or aircraft during that time.