A trip to Farmoor Reservoir, Oxfordshire, with Andy J. produced the goods. The juvenile American Black Tern(above) and juvenile White-winged Tern(below) were both present, along with a juvenile (Eurasian) Black Tern to compare with the American. The American looks quite a lot darker than its European counterpart, with obvious grey flanks, and it was good to have both to compare and study for a long period.
More photos below of American Black Tern in flight, with a Black-headed Gull, and White-winged Black Tern and American Black Tern together:
A large number of hirundines were also present, plus three Swifts.
Yesterday morning I saw my first Arctic Tern of the year at Frampton on the Sailing Lake, a juv., along with a juvenile Black Tern and four Common Terns (3 ad. 1 juv.)