Id of a large tern

[David]

When I was in the Cadiz area in hte second week of September I did some bird watching at the saltmarshes at Barbate and  I spotted a large tern.  It was stood on a mud bank in the middle of the Rio Barbate with some other waders and gulls.
I thought it was a Caspian Tern in non-breeding plumage but I have just been going through my bird notes and sketches and realise that it wasn't.  The crown was not all black.  Most of the head was white and only had black at the rear of the crown and part way down the nape.  The black also extended in a strip to the eye.
I have noted that it had a stout bright orange bill, white under plumage, soft grey wings with black primaries.  The legs were black.  In flight its tail was white.  I have also noted that stood close by were some Sandwich Terns and it was noticeably larger.
I think this tern could have ben a Royal Tern (Sterna maxima) in non-breeding plumage.  What do you all think?

Regards
David

[john]

An interesting record, but if you look on the 'rare birds in Spain' website there are a number of reports of  'odd' terns ('hybrid'?) terns knocking around which are very similar to Royal Tern.  I fear that a more detailed description or better still good photos are needed to make a definitive judgement,

John

[David]

John,

Thank you for your reply.  I looked at the Rare Birds in Spain website and found the hybrid terns that you mentioned.  The tern I spotted was not like the hybrid tern shown.

But on that website, above the description of the hybrids, was a description of a sighting of two Royal Terns in the Cadiz area in September.  The tern I saw looked just like the adult in the photograph so I think it may have been a Royal Tern.  Unfortunately, I did not have a camera with me so we will never know for certain.

David

[john]

I forgot about the report of Royal Tern in Cadiz - given this context it sounds like you may well have seen the same bird(s)!

John

[Peter]

I forgot about the report of Royal Tern in Cadiz - given this context it sounds like you may well have seen the same bird(s)!
John

I agree, based on the reports for Cadiz, also appears in the October rarity thread on here, that there was a good chance you saw Royal Tern David.

Peter

[Peter]

Due to the misplaced password Andy Paterson has asked I make the following remarks on this ID:

I agree it sounds like a Royal Tern on size differential alone, but it is worthwhile noting the following:

- that there is nothing on the darkness of the primaries being on the upper or lower surfaces in flight (varies according to whether Royal or Caspian and is good separation point),

- juv/1W Caspians have a more orange bill than the adults; juv./1W Royals are also less orange.

- the note by someone on hybrid Lesser Crested x Sandwich means nothing with regard to size as they are same as a Sandwich or a Lesser Crested, which are basically very similar whilst Royal is notably larger (a point made by your correspondent).

- bill shape and length can separate Lesser Crested from Elegant and Royal (size of this apart), just as bill shape can separate Caspian and Royal at all ages.

- Royal is considered to be a rarity by the Spanish Committee and on the evidence given would not get through.

- This points up the need for a good description as well as photos when a possible rarity is seen and memory can play tricks, not knowingly, but what is writtenm at the time exists, what wasn't doesn't..


Peter / For and on behalf of Andy Paterson