Arctic Tern are very similar to Common tern and can be difficult to
separate. Here are some pictures that might help things along....
A) Adult Arctic Tern, 30
August 2007, Tjeldstø, Norway.
Note the short beak, short legs and long tail streamers (they project
beyond the wing tips)
B) Juvenile Arctic Tern,
30 August 2007, Tjeldstø, Norway
Note the dark beak, rounded head and short legs. Little in the way of
gingery brown tones on the back.
C) Juvenile Arctic Tern,
probably fresher than the bird in B), this bird has orange on the beak,
but the beak length and shape is still correct for Arctic Tern.
Juvenile,
Tjeldstø,
Øygarden 28 September 2005 (digiscoped)