A real swift day. Calm, sunny most of the day and warmer. All four swifts were out before 8am. Around lunch time I had my first screaming swifts flying and screaming round the house. I am sure they were the four from our house. Impossible to photograph but I will keep trying. Only one clip. It’s not in focus but does show a parasitic common swift louse fly. They stay dormant in the nest all year waiting for the swifts return. It is not thought that they cause them any harm. Not seen them before in these two nests. Hard to see but a white small mark on the swifts back.