Includes annex: Results for Northwest England.

To support delivery of the latest census of the breeding seabird population of Britain and Ireland, a previous Natural England commissioned report (Ross et al. 2016) reviewed the survey methods in order to make recommendations for the most cost-effective survey design for quantifying (urban) gull abundance in UK and Ireland. Within that report, recommendations were made on the expected necessary coverage, with reference to previous analogous bird surveys across similar geographic scales.

This report builds on Ross et al. (2016) using computer simulations to examine how survey coverage affects the precision of population estimates. This work will provide a first step towards improving the population estimates of urban gulls, assuming surveys go ahead in the future.