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	(Ross's Gull header by Dave Hawkins)

Related Articles • Caspian Gulls in Suffolk, UK • A putative Heuglin's Gull L.heuglini in Norfolk, UK • Baltic and Heuglin's Gulls • 3rd yr Lesser Black-backed Gulls • Caspian Gull Photo Essay • Yellow-legged Gulls on Canaries • Identification of Juvenile Yellow-legged Gulls L. michahellis • Thayer's Gull - good species or not? • Thayer's Gull Photo Essay More Identification Articles on Surfbirds >> Gulls: A Guide to Identification, 2nd Edition Amazon.com Amazon.co.uk Latest Birding Books >> Latest Book Reviews >> Stay on top of all the latest world birding news every week. It's Free and Private! subscribe unsubscribe Photo © Roy Harvey		Table of Contents >> Introduction | Plates 22-46 | Acknowledgements 1. Bird A. Adult hybrid Yellow-legged x Herring Gull, Zeebrugge, May 2001 (©Laurent Raty). Colour-ringed as a chick at Rotterdam, The Netherlands, on 20 June 1992. Green ring on right leg, with white code "AH6". In 2001, this bird was paired with a Lesser Black-backed Gull, and successfully reared three young (backcrosses). It returned to the Zeebrugge colony in spring 2003. Strangely enough, its upperparts were darker grey than in Yellow-legged Gull, and it did not choose one of the parent species to mate with. Note also the very broad white scapular and tertial crescents. 2. Bird A, in flight. Zeebrugge, May 2001 (©Laurent Raty). The primary pattern is identical to that of some Yellow-legged Gulls 3. Bird A. Maine-et-Loire, France, 10 January 2003 (©Alain Fossé). Interestingly, "AH6" was also recorded outside of the breeding season, namely in France on 24 December 2001 and 10 January 2003. On both dates, its head was immaculately white. For more photographs and further details, see http://www.digimages.info/goeargleu/goeargleu.htm#AH6 and http://www.lpo-anjou.org/baguage/goeargleu_bag.htm. Compare also with photos 45-46. 4-5. Bird B. Adult hybrid, Zeebrugge, 22 April 2000 (©Leo Janssen). This bird wore a metal ring, but it was never read in the field. Compare the colour of the upperparts with that of nearby Herring and Lesser Black-backed Gulls. Note also the broad white tertial and scapular crescents. 6 Bird B. Zeebrugge, 22 April 2000 (©Leo Janssen). Display call. 7. Bird B. wing pattern. Zeebrugge, 22 April 2000 (©Leo Janssen). Note how the black pattern reaches far up towards the primary coverts on the outermost four primaries, yet this is combined with a rather narrow black band on p5 (broadest on the outer web), and a large white mirror on p10, showing only very little or no black near the tip. 8. Bird B. Zeebrugge, April 2001 (©Peter Adriaens). Probably the same bird as in photos 4-7, but one year later. The primary pattern has not changed. 9-10. Bird B. Zeebrugge, June 2001 (©Peter Adriaens). Primary moult has not started yet, while it had in all Herring and Yellow-legged Gulls on this date. The white trailing edge to the secondaries is very broad, much broader than the white tips to the inner primaries. Note the question mark in the grass on the left of the bird, in photo 9! 11-12. Bird B. Zeebrugge, August 2001 (©Peter Adriaens). Even this late in the season, the white tertial crescent is still very broad. In photo 10, it can be seen that primary moult has finally started (inner two primaries are missing). 13. Bird B(?). Zeebrugge, 1 May 2002 (©Koen Verbanck). Possibly the same bird as in photos 4-12, but one year later. If it is the same, the amount of black on p5 has decreased. 14-15. Bird C. Fourth summer presumed hybrid, Zeebrugge, June 2001 (©Laurent Raty). A slightly paler grey bird, quite similar to Yellow-legged Gull, but note the broad white scapular and tertial crescents, as well as the relatively large white primary tips (particulary for a 4th-summer bird). 16-17. Bird C. in flight. Zeebrugge, June 2001 (©Laurent Raty). Black marks on primary coverts, combined with absence of a white mirror on p9, and presence of but a small one on p10 are indications that this is not a full adult. The black band on p5 is slightly interrupted at the shaft, which is probably rare in fourth summer Yellow-legged Gull. The white trailing edge to the secondaries is very broad. Primary moult has not started yet. 18. Bird D. Adult presumed hybrid, Zeebrugge, May 2002 (©Peter Adriaens). Another slightly paler grey bird, similar to Yellow-legged Gull and yellow-legged Herring Gull. Note the broad white scapular and tertial crescents, and (compared to Yellow-legged Gull) the rather large white primary tips. 19. Bird D. in flight. Zeebrugge, May 2002 (©Peter Adriaens). This bird's primary pattern was most similar to that of a Herring Gull -- but the upperparts were darker grey than in any local Herring Gull. Primary moult has already started (p1 has been shed). Birds from eastern Baltic countries can look exactly like this (though with slightly narrower tertial crescent), but are certainly not expected to hold a territory in Belgium in May... 20-21. Bird D. in flight. Zeebrugge, May 2002 (©Peter Adriaens). At least on the left wing, the black band on p5 is incomplete. Table of Contents >> Introduction | Plates 22-46 | Acknowledgements