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. 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.

Waterbirds in the UK presents the summarised results of the annual WeBS report, and full data available via the WeBS Report Online. It provides a single, comprehensive source of information on the current status and distribution of waterbirds in the UK for those interested in the conservation of the populations of these species and the wetland sites they use.

This report examines the movements and habitat use of Herring Gulls Larus argentatus breeding in the Morecombe Bay SPA.

Capsule: The use of call-broadcasting significantly increases the number of Tawny Owls Strix aluco detected in winter point counts, but requires careful survey design to avoid introducing potential sources of bias into population estimates. Aims: To examine Tawny Owl response to call-broadcasting to aid survey design in national monitoring efforts. Methods: A nocturnal survey was undertaken at 36 survey points over three nights in winter in Thetford Forest, England. Each survey consisted of four consecutive five-minute segments: a passive count, followed by three counts with the use of call-broadcasting. Results: Few (4%) Tawny Owls were recorded during passive surveys, whereas the greatest response was during the first and second call-broadcast segments (49% and 36%, respectively). New detections declined to 11% in the final segment. Response was fastest at dusk, although time of night did not significantly affect the number of individuals detected. Male owls accounted for 79% of detections. Conclusion: Our results show that ten minutes of call-broadcast surveying will detect 85% of responsive Tawny Owls, thus vastly improving detection compared to passive listening alone. However, simultaneous counts of geographically separated detections should be used to provide a minimum count and reduce potential double-counting of mobile individuals.