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In 2009-2011, 27 Caspian Gulls Larus cachinnans were seen during standardized ESAS bird counts by IMARES and during pelagic trips by Pterodroma Adventures. The most westerly record was approximately 85km off Scheveningen, demonstrating that Caspian Gulls can occur at considerable distances from land. Both here, were birds were seen scavenging behind a beam trawler, and during the pelagic trips when chum was provided, Caspian Gulls were often foraging just behind the boat – where competition with other gulls is heaviest. As expected, the age distribution of the birds is heavily skewed to juveniles. The small number of adults is however surprising and either reflects a true lower abundance of adults at sea or an effect of lower detectability of adults in gull flocks. The fact that only recently the offshore occurrence of Caspian Gulls has been revealed is at least for the ESAS surveys undoubtedly an observer effect, but the absence of Caspian Gulls during Pterodroma Adventures pelagic trips in 2007-2008 remains puzzling.