LEFT: adult Mediterranean Gull, March 18 2003.

Mediterranean Gulls used to breed in a restricted area in the countries north of the Mediterranean, the Black Sea and east to Dagestan. When Karel Voous wrote his Atlas of European Birds (1965) the distribution of this species was so limited that he suggested that it might be heading for extinction. Since the late 1980’s this species has spread north and the world population has increased spectacularly. It now breeds regularly in Belgium, the Netherlands, England, Ireland, Hungary and Poland. After the breeding season, Mediterranean Gull disperse westwards and can be found south along the Moroccan Atlantic coast and along the coasts of the Mediterranean. Large flocks congregate at the beaches of Boulogne-sur-Mer (NW France) from August to October, later moving southwards. In early spring tens of thousands can be seen at Cambrils on the north-eastern coast of Spain.

Most images on this page were taken at Le Portel / Boulogne-sur-Mer, France (50.42. 20 N,01.34.03 E).  Le Portel is known to be one of the best sites to see Mediterranean Gulls with numbers exceeding 3.000 individuals during some autumns. As can be seen in the images, many individuals are colour ringed or metal ringed, and come from Mediterranean Gull populations from all over Europe. Colour-ringing Mediterranean Gulls started in The Netherlands in 1989 with only a handful of birds. Twenty years on thousands of birds have been colour-ringed and at the start of 2008 there are tens of projects all over Europe.

Mediterranean Gull is a medium sized gull, with an intense black head in adult summer and rather pale grey upper-parts. Easy clues for identification and ageing in Mediterranean Gull are the median coverts and outer primaries. Most of the description below follows P.J. Grant: "Gulls, a guide to identification".

1CY MEDITERRANEAN GULL

In juvenile plumage, the head is uniform pale buffish-brown with slightly darker ear-coverts and a pale throat. Juvenile birds have a blackish smudge in front of the eye and white crescents above and below the eye. The brown colour of the head extends onto the neck, forming a barred collar running down along the sides of the breast to the flanks. The under-parts and rump are white. The scapulars and mantle feathers are deep brown with an inconspicuous dark sub-terminal band and a silvery-white fringe, creating a scaly pattern.

The pattern of the scapulars is repeated on the lesser coverts, lower lesser coverts, median coverts, inner three to four greater coverts and upper tertials which also show brown centres and neat silvery-white fringes. They contrast strongly with the central and outer greater coverts, which are predominantly grey, forming a pale bar in the dark inner-wing in flight, as the secondaries are dark blackish-centred as well (but with broad white tips). The inner primaries are largely white-grey, the grey slightly decreasing in the primaries outwards, reduced to parts of the inner-webs in the outer primaries P9 and P10. The under-wing coverts are all-white, but there are neat black tips on the under-wing greater primary coverts. The white tail has a clear-cut black sub-terminal band, widest on t1-2, very thin on the outer rectrices (t6 can be completely white). The iris is dark brown, the legs are usually very dark horn, the bill is blackish.

The complete juvenile plumage lasts for only a short period in Mediterranean Gulls as they start to moult soon after fledging. This post-juvenile moult is a partial moult into so-called "first winter" plumage that starts from the moment the birds leave their colonies in July and will be finished by late September. This moult includes most of the head and body feathers. The head and under-parts become almost completely white, with a dark mask of variable size and intensity behind the eye extending as very narrow streaks over the nape. The eye-crescents are white and the dark smudge in front of the eye contrasts more than in full juvenile plumage. The second generation wing-coverts, mantle and scapular feathers are plain pale grey. The rich brown centres of the juvenile wing-covert centres bleach to a foxy brown and the white fringes quickly wear away. In most birds at least some wing-coverts are included in the post-juvenile moult. The extent of this covert moult is variable, in a few birds nearly all are moulted, in others all juvenile coverts are retained until the next complete moult that starts in May of the next year. All juvenile feathers show wear by September, contrasting with the recently moulted second generation feathers. The base of the bill starts to turn paler and the legs turn slightly paler as well.

Note that the comments on moult are based on observations of juveniles from and in Western Europe. More easterly fledged Mediterranean Gulls may postpone their moult to first winter until later in the autumn and very fresh looking juveniles may be encountered well into October.

2CY MEDITERRANEAN GULL

The next moult in Mediterranean Gull is again a partial moult, from February to April and includes body and head resulting in a so-called "first summer" plumage. Most noticeable is the replacement of head feathers: the head becomes much darker with some birds developing a full hood, but many only have some black flecking. The remiges and rectrices remain juvenile and by April have become bleached and abraded. Some individuals include inner wing-coverts in this partial moult, but the juvenile outer wing-coverts are retained and therefore very abraded. The colour of bare parts become more adult-like, with the bill-base turning paler red-orange. Most birds have extensive black on the bill tip, most prominent on the lower mandible. This is the most variable plumage in Med Gull since the appearance of 2cy birds depends on the combination of the extent of the post-juvenile moult, and bleaching and wear in the winter quarters

From May to September, the first complete moult takes place, into so-called "second winter" plumage. The head pattern resembles the pattern in first winter birds, with a blackish mask behind the eye. The mantle, scapulars, tertials and all wing-coverts are replaced with plain pearl-grey feathers. The secondaries are as in adult birds, pale grey with a white tip. The second generation primaries are much paler than the first juvenile primaries, but still not nearly all-white as in adults. After finishing this complete moult a 2cy Mediterranean Gull in autumn has a diagnostic wing-tip pattern with a variable amount of black on P5-P10. P5 has only a small black sub-terminal spot, becoming gradually larger on the outer primaries as the black patch "eats up" the white along the edge of the outer-web, most prominent on P9-P10. In some birds, the outer greater primary coverts and rarely the alula coverts may show dark markings as well. The bill is orangey-red with a dark sub-terminal band. The legs are dull red or more obvious orangey-red. As with 2cy birds there is individual variation in this age group but it is less pronounced and mostly involves the amount of black in the outer primaries and the colour of the bill.

3CY MEDITERRANEAN GULL
Next moult in Mediterranean Gull is again a partial moult, from February to April and includes body and head, bringing birds in so-called "second summer" plumage. Most noticeable is the replacement of head feathers: the head becomes darker with birds developing a full hood, some still show limited flecking. The white tips of the primaries become slightly worn. The colour of bare parts become adult-like, with the orbital ring and bill turning coral red, the bill often with a thin black bill-band. The legs are scarlet red. The iris turns deep reddish-brown.

From late summer to September, a complete moult takes place, into so-called "third winter" or "adult winter" plumage. The head pattern resembles the pattern in first winter birds, with blackish mask behind the eye. The mantle, scapulars, tertials and all the wing-coverts are replaced for plain pearl-grey feathers. The secondaries are completely white. The adult primaries are shiny pearly-grey, flashing white at a distance. There is a black line along the outer-web of P10 (and sometimes on P9 as well). Secondaries, under-wing and tail all completely white. The bare part coloration in adult plumage: Iris brown, orbital ring red or orangey-red, the bill red or orangey-red with a black bill-band and a yellowish tip and the legs dull reddish or dark.

The next moult in Mediterranean Gull is again a partial moult, from February to April and includes body and head, bringing birds in so-called "second summer" plumage. Most noticeable is the replacement of head feathers: the head becomes darker with most birds developing a full hood, some still show limited flecking. The white tips of the primaries become slightly worn. The colour of bare parts become adult-like, with the orbital ring and bill turning coral red, the bill often with a black bill-band of varying width. The legs are scarlet red. The iris turns deep reddish-brown. As with 2CY birds there is individual variation in this age group but it is less pronounced and mostly involves the amount of black in the outer primaries and the fullness of the hood.

From June to September, a complete moult takes place, into so-called "third winter" or "adult winter" plumage. The head pattern resembles the pattern in first winter birds, with blackish mask behind the eye. The mantle, scapulars, tertials and all the wing-coverts are replaced for plain pearl-grey feathers. The secondaries are completely white. The adult primaries are shiny pearly-grey, flashing white at a distance. There is a black line along the outer-web of P10 (and sometimes on P9 as well). Secondaries, under-wing and tail all completely white. The bare part coloration in adult plumage: Iris brown, orbital ring red or orangey-red, the bill red or orangey-red with a black bill-band and a yellowish tip and the legs dull reddish or dark. There is some variation in 3cy and 4cy wing-tip patterns.

ADULT MEDITERRANEAN GULL

The next moult in Mediterranean Gull is again a partial moult, from December to March-April and includes body and head, leaving birds in so-called "adult summer" plumage. The head develops a jet-black hood, extending down the nape. Adult birds have broad and contrasting white crescents above and below the eye. The bare part coloration in adult plumage: Iris brown, orbital ring coral red, the bill scarlet red often with a thin black bill-band and a yellowish tip and the legs red.

Adult Mediterranean Gulls have established several new colonies on the northern borders of their distribution. They now breed regularly as far west as Britain and north to the Netherlands and Poland. Ring recoveries demonstrate that in spring adults may do a tour of Europe visiting colonies on the way and moving on quickly when the local breeding circumstances are not completely satisfactory. A nice example is white 24R, a bird ringed as adult on the nest in the Netherlands in May 1998. As so many Mediterranean Gulls, this individual has usually spent the period from late-summer to early spring at Le Portel. In between it has looked for breeding locations in the Netherlands, Belgium and Hungary. Despite intensive searches in the Zandvliet colony, it doesn't seem likely that 24R has ever bred here. In four consecutive years, this colony was visited early in the breeding season when it also functions as a roost, but there have been no records after late April. The sightings in Hungary in 1999, when it was definitely breeding, and at the end of the breeding season in 2007 are interesting. There are no sightings from the breeding season in other years but it seems that this bird has permanently switched to breeding in eastern Europe. This life-history also demonstrates how easily birds may travel within Europe. The sightings in July 2007 show that they navigate without difficulty to the main moult and feeding-location of Le Portel in NW France, where autumn groups always include some eastern Mediterranean Gulls from Italy, Poland, Hungary and even the Ukraine.

A summary of the records for White 24R/9AP with thanks to P.L. Meininger, R. Flamant and C. Duponcheel of the Mediterranean Gull colour-ring programme:

• ringed May 27 1998 to July 01 1998 at Hellgatsplaten, the Netherlands (3 records)
• from July 23 1998 to February 27 1999 at Le Portel, France (27 records)
• from April 03 1999 to April 14 1999 at Zandvlietsluis, Belgium (7 records)
• June 17 and 18 1999 at Mekszikópuszta, Hungary (2 records)
• from July 30 1999 to March 07 2000 at Le Portel, France (12 records)
• from April 08 to 12 2000 at Zandvlietsluis, Belgium (3 records)
• from July 25 2000 to March 10 2001 at Le Portel, France (26 records)
• from April 17 to 23 2001 at Zandvlietsluis, Belgium (5 records)
• from July 25 2001 to October 10 2001 at Le Portel (11 records)
• April 01 to 17 2002 at Zandvlietsluis, Belgium (4 records)
• from July 26 2002 to March 15 2003 at Le Portel (17 records)
• March 23 2003 at Berendrecht, Belgium (close to Zandvlietsluis), re-ringed 9AP
• from July 30 2003 to October 16 2003 at Le Portel, France (8 records)
• from February 10 2004 to February 27 2004 at Le Portel, France (4 records)
• from July 30 2004 to October 26 2004 at Le Portel, France (12 records)
• February 23 2005 at Le Portel, France
• from July 28 2005 to February 2 2006 at or near Le Portel, France (37 records)
• from July 27 2006 to November 3 2006 at Le Portel, France (19 records)
• July 10 2007 at Mekszikópuszta, Györ-Sopron, Hungary
• from July 19 2007 to February 19 2008 at Le Portel, France (15 records)

Biometry (measurements in mm’s) wing: 282-311, tail: 113-127, bill: 31-38, tarsus: 48-58; n = 21 (Dwight, 1925);

Impression of a mixed resting flock of Mediterranean Gulls, with Black-headed, Herring, Common, Great Black-backed, Lesser Black-backed and Yellow-legged Gulls in the evening of 06 February 2003, at the Rolo Parking of Boulogne/Mer, NW France.

Where do coloured ringed Mediterranean Gulls come from:

Small group of adult Mediterranean Gulls on the beach of Le Portel - NW France, preparing to leave this wintering quarter for the breeding grounds. Considering the green ringed bird in the front, these adults breed among others in Belgium and northern France. March 2003.