SUMMARYSalmonella carriage in 5888 gulls sampled by cloacal lavage was found to be 7-8 %. Marked geographical and seasonal differences in carriage rates were found.These differences appeared to be associated with human population density and seasonal differences in the reported incidence of human salmonellosis. The maximum duration of salmonella excretion in 17 laboratory-maintained gulls was 4 days and the number of salmonellae excreted was never more than 170 per gram of faeces. On the basis of this study it is suggested that gulls are not important factors in the aetiology of human salmonellosis.

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JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact support@jstor.org.. Wiley and Nordic Society Oikos are collaborating with JSTOR to digitize, preserve and extend access to Ornis Scandinavica. Shedden, C. and Thomas, C. 1984. Scandinavian Herring Gulls wintering in Britain. -Ornis Scand. 15: 79-88.Biometric information was obtained from 13000 Herring Gulls Larus argentatus caught and ringed in northern England and southern Scotland outside the breeding season between 1978 and 1983. Morphological differences between males and females and between British and Scandinavian Herring Gulls have been used to identify both the sex and race of the birds. We describe the wintering distribution of the Scandinavian birds in Britain, their age and sex ratios and their time of arrival in and departure from Britain. Scandinavian Herring Gulls start to arrive in Britain in small numbers in September. The proportion of Scandinavian birds increases to a peak in December-January and the birds depart abruptly in late January or early February. Very few Scandinavian Gulls penetrate to the west side of Britain, while on the east side there is considerable regional variation in the proportion of Scandinavian birds. Between 70% and 80% of the adult Scandinavian birds examined were female. The proportion of adults amongst Scandinavian birds was much higher than amongst British birds.