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

By using the BTO's ring-recovery database, this report analyses the dispersal movements of UK Barn Owls to inform placement of mitigation measures along the route of the HS2 rail-link.

This report explores means by which a standardised trend analysis of data from the Wetland Bird Survey (WeBS) can aid rapid assessment of condition for non-breeding waterbird SPAs in England. For supporting material please contact Natural England.

This report was commissioned by Natural England to inform the design and implementation of future census efforts for breeding urban gulls, and to make recommendations for the most cost-effective survey strategy for delivering urban gull population estimates for the UK and Republic of Ireland, as well as any specified key sites.

Every year, volunteers across the UK take part in the BTO/RSPB/JNCC Breeding Bird Survey (BBS), recording breeding birds in randomly selected 1-km squares (stratified regionally by observer availability) to robustly monitor population trends of some UK bird species. However, the chances of randomly selected squares containing rarer bird species and the habitats of interest that only cover a small proportion of the landscape are low, limiting our ability to monitor population changes. The work reported here examines options for increasing coverage of rare species and of assemblages occupying certain habitats of interest within the BBS framework, by including additional strata based on habitat type. It also assesses the benefits and risks of including an additional stratum based on accessibility to increase volunteer uptake in large regions with low observer density and many inaccessible areas. Volunteer recruitment is often difficult in these regions because randomly selected unmonitored BBS squares may require long drives, difficult walks and over-night camping.

The purpose of this work was to develop a method for analysing digital aerial ornithology survey data, to derive species-specific flight heights. The focus of this work has been to develop an approach to analysis, rather than analysing a comprehensive dataset to derive generic flight height values. Although the project has been successful in developing such an approach to analysis, the BTO and Steering Group for the work emphasises that the values presented in this report are not intended to be used to inform assessments. Any party undertaking an ornithological collision risk assessment should seek advice from the relevant regulators and statutory nature conservation bodies on appropriate flight height values and avoidance rates to use. This report does not constitute such statutory advice.

The height at which seabirds fly is a key factor in determining how these birds interact with offshore wind farms. Of particular interest is the need to accurately predict flight heights, in order to feed these data into the predictive 'Collision Risk Models' used to identify the potential impacts of wind farms on seabird populations. Flight height data have traditionally been generated volunteer observers in boat surveys, but different methods are now being used to estimate the flight heights of birds. The relative suitability of methods estimating flight heights had not been rigorously appraised. This report details and compares the different methods for estimating flight heights, evaluating the relative merits and disadvantages of each method.