CAMPHUYSEN CJ & VREEZE F DE (2005) Black-legged Kittiwakes Rissa tridactyla nesting on an offshore platform in The Netherlands. LIMOSA 78 (2): 65-74.

In summer 2000, personnel of Wintershall AG reported chicks of gulls on the offshore platform L8-P in the Southern Bight (65 km NW of the island of Texel, The Netherlands). The gulls turned out to be Black-legged Kittiwakes, a cliff-nesting seabird that had never bred in The Netherlands before. A visit by Wintershall staff in 2001 confirmed the presence of at least 3 nests.
      L8-P is an uninhabited gas-exploitation platform at 53°38.5'N, 04°34'E, in 32 m deep water, an area known as the Frisian Front (a separation zone between turbid water of the Southern Bight and clear, saline water of the Central North Sea). No information was received since then and a visit planned for 2004 had to be cancelled. On 22 June 2005, however, a full day was spent on the island and a colony census could be conducted successfully. On eight different locations, with most nests (62.2%) along the east and southeast side of the platform (Fig. 1), 45 apparently occupied nests were found. Of these, 22 nests were empty, eight contained a single egg, and 15 held two eggs. The mean egg size was 55.84 x 39.98 mm, with no difference between single egg and double egg clutches. Samples of guano and nest material were taken, and these suggested that the birds fed mainly on small sandeels Ammodytes spp. and Sprat Sprattus sprattus (calculated fish length 5-15 cm; Table 2). The nests were built of a mixture of natural materials (seaweeds such as Fucus vesiculosus, Euteromorpha spp., Flustra foliacea, and Ascophyllum nodosum) and all kinds of plastics and nylon.
      Mean clutch size was low, perhaps typical for a newly established colony, but the prospects for this site seem promising, except for a limitation of nest sites. The food situation is likely to be excellent, as previous observations on seabirds in this part of the North Sea have shown. The results show that the birds focussed on natural prey rather than on discards (in sharp contrast with the prey remains of large Larus gulls found on the helicopter deck of the same site. The few available data suggest exponential growth of the colony. If the Kittiwakes on L8-P turn out to be successful breeders, one might expect a near-future colonisation of a number of nearby unmanned platforms that have not yet been colonised. Black-legged Kittiwake Rissa tridactyla

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