JANSEN FH & REMEEUS A (1978) To a definite establishment of the Mediterranean Gull Larus melanocephalus in The Netherlands?. LIMOSA 51 (3): 88-106.

Mediterranean Gull Ichthyaetus melanocephalus = Larus melanocephalus In section 3 records from various periods are presented in several ways (Fig. 1-5) to show the establishment of the Mediterranean Gull in The Netherlands. It shows distribution in all seasons ~ including breeding cases~ and waterside attachment. . 2. In section 4.1 records from personal sources are .presented as proof for regular occurence of Mediterranean Gulls in autumn at Scheveningen. The chance to see a Mediterranean Gull varies between 0 and 17%. 3. In section 4.2 details about a wintering Mediterranean Gull at Scheveningen are given, including the remarkable change in head and bill patterns, described in section 4.2.1 (Fig. 9). Determination of age seems impossible, unless the,black bill is only a winter fieldmark, though not always present (Fig. 10). . 4.. In section 4.2.2 a sequence of displays of two Mediterranean Gulls, apparently a couple, 'is described with the aid of Fig II. 5. In section 5 a new survey of. records, collected by Mayaud (1954, 1956) and Schewarewa (1956), is made (Fig. 13) and used for analyses of non-breeding and breeding distribution (Fig. 12). As migration system a westward spread based on statistical principals is suggested. 6. There are enough arguments for the opinion thatthe Mediterranean Gull has obtained a strong foothold in NW-Europe and The Netherlands and it is recommended to lend the Mediterranean Gull the status of 'resident as a species' or atleast 'non-breeding resident'.

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