Last night we (Stour Ringing Group) ringed the Barn Owl chicks at Swineham, which I will write about later. However, about an hour after we had finished I sat in the dark with my recording gear, sound recording the adults coming back and forth with food. In this recording you can initially hear standard begging calls that occur once every second or so, and then as you can see on the sonagram at 13 seconds an adult enters the box, the squabbling begins and the begging calls speed right up.