Migrant bird. Compare with the Black Tern: note the dark saddle (with a few new grey feathers), the pale wing panel, the longer legs, the large white patch between the nape and the ear-coverts, the reduced black crown.
Migrant bird. Compare with the Black Tern: note the dark saddle (with a few new grey feathers), the pale wing panel, the longer legs, the large white patch between the nape and the ear-coverts, the reduced black crown.