White-winged black tern at Tyttenhanger GPs, London Colney, Herts (Tue 12 Sep 2017)

White-winged black tern at Tyttenhanger GPs, London Colney, Herts (Tue 12 Sep 2017)

White-winged black tern at Tyttenhanger GPs, London Colney, Herts (Tue 12 Sep 2017)

White-winged black tern at Tyttenhanger GPs, London Colney, Herts (Tue 12 Sep 2017)

White-winged black tern at Tyttenhanger GPs, London Colney, Herts (Tue 12 Sep 2017)

White-winged black tern at Tyttenhanger GPs, London Colney, Herts (Tue 12 Sep 2017)

White-winged black tern at Tyttenhanger GPs, London Colney, Herts (Tue 12 Sep 2017)

White-winged black tern at Tyttenhanger GPs, London Colney, Herts (Tue 12 Sep 2017)

White-winged black tern at Tyttenhanger GPs, London Colney, Herts (Tue 12 Sep 2017)

White-winged black tern at Tyttenhanger GPs, London Colney, Herts (Tue 12 Sep 2017)

White-winged black tern at Tyttenhanger GPs, London Colney, Herts (Tue 12 Sep 2017)

White-winged black tern at Tyttenhanger GPs, London Colney, Herts (Tue 12 Sep 2017)

White-winged black tern at Tyttenhanger GPs, London Colney, Herts (Tue 12 Sep 2017)

White-winged black tern at Tyttenhanger GPs, London Colney, Herts (Tue 12 Sep 2017)

White-winged black tern at Tyttenhanger GPs, London Colney, Herts (Tue 12 Sep 2017)

White-winged black tern at Tyttenhanger GPs, London Colney, Herts (Tue 12 Sep 2017)

White-winged black tern at Tyttenhanger GPs, London Colney, Herts (Tue 12 Sep 2017)

White-winged black tern at Tyttenhanger GPs, London Colney, Herts (Tue 12 Sep 2017)

White-winged black tern at Tyttenhanger GPs, London Colney, Herts (Tue 12 Sep 2017)

White-winged black tern at Tyttenhanger GPs, London Colney, Herts (Tue 12 Sep 2017)

White-winged black tern at Tyttenhanger GPs, London Colney, Herts (Tue 12 Sep 2017)

White-winged black tern at Tyttenhanger GPs, London Colney, Herts (Tue 12 Sep 2017)

White-winged black tern at Tyttenhanger GPs, London Colney, Herts (Tue 12 Sep 2017)

White-winged black tern at Tyttenhanger GPs, London Colney, Herts (Tue 12 Sep 2017)

White-winged black tern at Tyttenhanger GPs, London Colney, Herts (Tue 12 Sep 2017)

White-winged black tern at Tyttenhanger GPs, London Colney, Herts (Tue 12 Sep 2017)

White-winged black tern at Tyttenhanger GPs, London Colney, Herts (Tue 12 Sep 2017)

White-winged black tern at Tyttenhanger GPs, London Colney, Herts (Tue 12 Sep 2017)

White-winged black tern at Tyttenhanger GPs, London Colney, Herts (Tue 12 Sep 2017)

White-winged black tern at Tyttenhanger GPs, London Colney, Herts (Tue 12 Sep 2017)

White-winged black tern at Tyttenhanger GPs, London Colney, Herts (Tue 12 Sep 2017)

White-winged black tern at Tyttenhanger GPs, London Colney, Herts (Tue 12 Sep 2017)

White-winged black tern at Tyttenhanger GPs, London Colney, Herts (Tue 12 Sep 2017)

White-winged black tern at Tyttenhanger GPs, London Colney, Herts (Tue 12 Sep 2017)

White-winged black tern at Tyttenhanger GPs, London Colney, Herts (Tue 12 Sep 2017)

White-winged black tern at Tyttenhanger GPs, London Colney, Herts (Tue 12 Sep 2017)