Originally Posted by JANJ
On my monitor the left tern shows a greyish uppertail with white sides.
If I understand you right Sean - by saying that 'all the primaries' should be black on a Saunderīs Tern - you really mean that Saunderīs has a 'wider' black area on outer
primaries compared to Little Tern.
As staded in an earlier post I find it difficult to be sure of the identification of these two in this image (no disrespect Adrian
). I for once canīt see the head pattern properly, because thatīs what I want to see before I draw any conclusions. We also have to consider that Little Terns in the area might show grey central tail (but paler rump) and intergrades occcur.
Any more Adrian?
I will re-phrase what I wrote..as it was bad. Yes I meant that the black area on the outer primaries is wider in adults in full breeding plumage in Saunder's than Little. In 1st year birds, it is often most of the primaries that are black if memory serves (which it often doesn't).
Now I couldn't see the greyish upper tail on the left-hand bird in the first photo, but in the reposted photos..the bid on the right does appear to have some grey on the rump and inner tail.
You mention that Little might have a greyish central tail and paler rump. Agreed..but in winter plumage in Little it should be all white, though of course these birds are coming into, if not in breeding plumage and often Little has all grey rump and upper tail as Saunders. Moreover Ist year saunder's often have white rumps and tails. I hadn't considered intergrades.
The face pattern on the second posting looks good for the two species. The bird on the left in the second posting is definitely Little, the bird on the right is most likely Saunders, but I guess one still can't rule out a 1st winter Little Tern coming into breeding plumage for the first time.
I had not mentioned leg color, but as Jan points out it is the same in winter, both have dark legs and bill, attaining only bright orange legs in Little in the summer, with as Howard points out Saunder's having dirty yellowish. Although the right-hand bird has dark legs it is not clear in the photo on my screen and it could be that the bird has not yet attained ful-breedng plumage, as the bill still looks a litle dark at the base.
I haven't seen Saunders Little Tern in 10 years, so admittedly a bit rusty too. Still great photos.