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 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 House Sparrow Passer domesticus has declined in urban areas across Europe since the late 1970s and is now listed as a species of conservation concern. Recent research into the causes of decline suggests that breeding populations may be influenced by a number of urban habitat features. These include pollution levels, insect abundance, nest site availability and the presence of predators. In this Research Report, we examine how the presence of certain features within the urban environment relates to the location of House Sparrow colonies.

This report documents analysis of Wetland Bird Survey data for the Stour and Orwell SPA, identifying changes in counts over a 10-year period for Knot, Dunlin and Black-tailed Godwit. Through this, it shows the value of the SPA for these species.

This report presents the results from a large-scale survey of wintering birds on a representative sample of lowland farmland in Britain – the Winter Farmland Bird Survey. The aims of the Winter Farmland Bird Survey were three-fold: first, to provide information on the distribution and abundance of a suite of farmland bird species across the whole of lowland Britain; second to describe the distribution and abundance of agricultural habitats in winter; and, third to identify the habitat preferences of farmland birds in winter across a wide geographic area and to investigate the importance of regional and seasonal differences. This report draws together much of the work undertaken on the Winter Farmland Bird Survey project, including published and unpublished work. It includes preliminary analyses that aimed to assess the strengths and weaknesses of the dataset (Supplementary Analysis, Chapter 9), and considers broad habitat associations (Chapters 2, 3), the importance of stubble fields (Chapter 4), landscape-level habitat associations (Chapter 5), regional similarities in drivers of distribution (Chapter 6), possible population-level responses of birds to winter habitat availability (Chapter 7) and investigating possible linkages between farmland and gardens (Chapter 8).