Wet walk across the barrage & back this morning. Wet weather had brought the Swifts down, although not as many as one would hope – I guestimate 30+, some flying across the barrage at head height. Similar with Sand Martins and a few House Martin, a number of the former landing to rest on the pontoons by the environment building. A pair of Ravens were sitting on the railings by the ‘sails’, and there were a number of Pied Wags including juvs.