BTO Research Reports are scientific papers that have been self-published by the BTO. The following is a full list of the published BTO research reports. Most are free to download, and links to Abstracts are included where possible.
Numbers missing from the list are those allocated but which were never produced or which have not been published. BTO recognises that, particularly in respect of commercially sensitive cases, a period of confidentiality is appropriate for some projects. However, in the interests of scientific development and dissemination of information, we encourage clients to permit publication as soon as it is reasonable to do so.
- If you wish to purchase a physical copy of a report please contact researchreports@bto.org.
- More information about our Annual Service reports to JNCC 1992-2005.
Assessment of recent Hen Harrier population trends in England through population modelling
This study uses a population modelling approach to explore the effects of changes in rates of productivity, survival, and settlement on population growth in the English population of Hen Harriers.

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Modelled changes to seabird presence and abundance across the MarPAMM region in response to predicted changes in climatic and oceanographic variables
Author: Bennett, S., Rhoades, J., Boersch-Supan, P., Humphreys, E.M., Davies, J. & Upton, A.
Published: 2025
As part of the suite of work for the BTO Northern Ireland Science Plan 2023—2028 for DAERA/NIEA, BTO was asked to provide an analysis and associated report to investigate climate change related change in seabird populations in and around Northern Ireland. In this report, we update previously estimated projections of change in seabird populations (Davies et al. 2023) based on newly available datasets, including data from Seabirds Count and updated NEMO and C3S oceanographic data. We also discuss the reliability of existing Interreg VA/MarPAMM projected changes, and the likely extent to which climate change is already driving alterations to seabird abundance. Overall, the population of seabirds in the Interreg VA/MarPAMM region is predicted to decline in presence and abundance by 2050 under climate change.
10.06.25
Research reports Research reports

Scientific support to the trial of Spoor AI at the European Offshore Wind Deployment Centre
Author: Brighton, C.H., Clarke, J.A. & Boersch-Supan, P.H.
Published: 2025
This report assesses the capability of a Spoor AI camera system with both mono-vision (single-camera) and stereo-vision capabilities for bird monitoring deployed at the European Offshore Wind Deployment Centre in Aberdeen Bay using both theoretical considerations and onshore and offshore field trials.
25.04.25
Research reports Research reports

A review of existing methods to collect data on seabird flight height distributions and their use in offshore wind farm impact assessments
Author: Feather, A.P., Burton, N.H.K., Johnston, D.T. & Boersch-Supan, P.H.
Published: 2025
This document presents a review of existing methods for collecting seabird flight height data and their potential to produce flight height distributions that might be used in CRMs. The strengths, weaknesses, and limitations of different methods are identified and sources of measurement and sampling error, uncertainty and bias assessed. Best practice recommendations are provided for prominent methods and how data might be best utilised to inform stakeholders is considered.
15.04.25
Research reports Research reports

Assessment of recent Hen Harrier population trends in England through population modelling
Author: Macgregor, C.J., Pearce-Higgins, J.W., Siriwardena, G.M., Wilson, M.W. & Robinson, R.A.
Published: 2025
This study uses a population modelling approach to explore the effects of changes in rates of productivity, survival, and settlement on population growth in the English population of Hen Harriers.
14.03.25
Research reports Research reports

Bat distribution and activity in the Skell Valley catchment, 2024 Report
Author: Newson, S.E. & Crisp, G.
Published: 2025
This report presents the main findings from survey work delivered using passive acoustic monitoring devices deployed across the Skell Valley catchment. Through the surveys that we support we aim to improve knowledge and understanding of species distribution and activity, covering a range of taxonomic groups, including birds, bats, small terrestrial mammals and insects. Through the approach we provide robust datasets that can be used to inform better decision-making processes.
07.03.25
Research reports Research reports
