A birder in New York State (eastern USA) photographed this Tern:
https://plus.google.com/u/0/phot ... 5897978668358994097
He believes it is
S. hirundo longipennis which I agree with. This would be the first record for Eastern USA. Since HK birders have a lot of experience with this race and NA birders rarely (Alaska) encounter it, he would like some comments on the ID.