Unfortunately the wrybills proved elusive. They are calm little birds, almost tame, and despite all Adrian's efforts to 'twinkle' them in the right place, they simply parted to allow him to move among them, then filled in again behind him! They would not be herded!
So, Plan C. Moving very gently, and with great skill, Adrian began to work just on the SIPO. They did herd. He didn't want them to take off, or all his time would have been wasted and they might have ended up at the end of the shell bank again. Slowly, slowly he pushed them towards the net area until there were plenty in the right place. For a long while we waited. Nothing seemed to be happening, but then someone who was on the other end of the radio said that Adrian was waiting while a couple of SIPO moved themselves a bit, as they were too close to the actual cannons.