Monitoring of inter-annual incidence rates and within-colony spatial heterogeneity in exposure to tick-borne infectious agents in a long-lived seabird - follow up

Seabirds in arctic colonies can be exposed to infectious agents that can be transmitted by vectors, such as ticks, or by direct contacts among individuals. Earlier studies have shown that the exposure to specific infectious agents can vary in space at a hierarchy of scales, but factors affecting the circulation of these agents and their negative effects on hosts are not well identified, despite their importance for the understanding the emergence of diseases in wild populations, notably of a species like the Black-legged kittiwake (Rissa tridactyla) which is classified as endangered (EN) on the Norwegian red-list of threatened species. The study has implications for the understanding of factors affecting the circulation of tick-borne infectious agents at high latitudes, notably in the context of climate change, with potential implications for health and seabird conservation. The aim of the project is to continue to study on the long term the dynamics of immunity against tick-borne infectious agents and its spatial variability within a colony of this species exposed to parasitism by the tick Ixodes uriae. More specifically, the aim of the project is to monitor inter-annual incidence rates and within-colony spatial heterogeneity in seroprevalence estimated by repeated determination of serology status in parallel to acquiring data on the demography of the species (annual survival). In order to enable meaningful comparisons, 220 adult individuals of the study species will be sampled/resampled and individually colour-ringed over the 2 year course of the study. Care to adhere to the demands for replacement, reduction and improvements was taken for the design of the study and will be for its implementation. The species was chosen notably because qualitative and quantitative data are required for addressing questions of conservation concern and for increasing public awareness on issues of negative demographic trends and potential emergence of diseases, thus it would not be possible to replace it. Care will be taken to subject the birds to the most limited distress when conducting the manipulation that will consist in the capture of the birds, ring marking and a small blood sample. Modelling will be done to optimize the use of data. Efforts to make use of proper statistical methodology for the data analyses and to ensure high detection rates in the field are made to reduce the number of animal used. The design used is specifically refined to enable exploring at the same time disease agent exposure and the demography of the birds.