The foraging pattern, microhabitat utilisation and community impact of Nucella lapillus was investigated by field observations and field interventions. Detailed recording sampling and experimental data were taken once every week (for two-three years), from each shore level (low, mid, upper), on each of six study shores varying in wave-exposure from very sheltered to very exposed. Results were compared in relation to those relevant environmental factors that affect dogwhelk activity, growth and survival. It was apparent that Nuce/la lapillus feeding and refuging patterns are detennined by a myriad of different factors including changes in the tidal cycle (and related environmental consequences), wave action, shore level, shore topography and exposure. On a local scale, prey size and availability, as well as microhabitat composition and availability, were important. In contrast to the North-Western Atlantic, populations of Nucella lapillus in North Wales do not seem to have keystone effects on the community structure of sessile assemblages, including their main prey item Semibalanus balanoides.