Near heart attack here - switched on the cam just in time to see what looked like somebody jumping off the ledge - and could see only three chicks. The two up front wouldn't move for the longest time, and with the light shining in, it was hard to tell if there was anybirdie in front of them. Finally one did move enough and the fourth one, farther down, moved to signal its presence. Oh dear, think I'll go back to watching the two bunnies racing around out on the lawn - not nearly so traumatic!