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 [email protected].
- 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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Analysis of Wetland Bird Survey (WeBS) data for The Humber Estuary SSSI, SAC, SPA and Ramsar site: fourth appraisal — sector-level trends to winter 2021/22
Author: Bowgen, K.M., Austin, G.E., Wetherhill, A. & Woodward, I.D.
Published: 2023
This study updates previous reports that assessed population trends of waterbird species in different parts of the Humber Estuary, in order to identify areas where species were declining contrary to, or in excess of, the trend for the Humber Estuary as a whole and, furthermore, to identify sectors that support an increasing proportion of species that are declining across the Humber Estuary as a whole.
01.12.23
Research reports Research reports

Strategic study of collision risk for birds on migration and further development of the stochastic collision risk modelling tool (Work Package 1: Strategic review of birds on migration in Scottish waters)
Author: Woodward, I.D., Franks, S.E., Bowgen, K., Davies, J.G., Green, R.M.W., Griffin, L.R., Mitchell, C., O’Hanlon, N., Pollock, C., Rees, E.C., Tremlett, C., Wright, L. & Cook, A.S.C.P.
Published: 2023
Report by British Trust for Ornithology, Royal Society for the Protection of Birds and ECO-LG to The Scottish Government, Crown Estate Scotland and The Crown Estate.
01.10.23
Research reports Research reports

Analysis of wintering waterbird population trends for the Lough Neagh and Lough Beg Special Protection Area (SPA)
Author: El Haddad, H., Austin, G., Woodward, I. & Booth Jones, K.
Published: 2023
This analysis of Wetland Bird Survey (WeBS) data for the Lough Neagh and Lough Beg SPA provides details of wintering waterfowl population changes around the loughs and assists in identifying potential research questions to be pursued.
24.08.23
Research reports Research reports

Bioacoustics as a novel approach for detecting the presence of Brown Rats on seabird islands
Author: Newson, S.E., Else, R., Crymble, J., Gilbert, G., Tosh, D.G. & Booth Jones, K.A.
Published: 2023
Static acoustic bat detectors were deployed over a six-month winter survey season, to explore the possibility for using acoustics to detect and monitor the presence of Brown Rats on Rathlin Island in Northern Ireland. This report provides an overview of the survey coverage and main results from 2022/23.This research used the BTO Acoustic Pipeline to process and analyse sound recordings.
27.07.23
Research reports Research reports

Assessing movements of Lesser Black-backed Gulls using GPS tracking devices in relation to the Galloper Wind Farm
Author: Green, R.M., Thaxter, C.B., Johnston, D.T., Boersch-Supan, P.H., Bouten, W. & Burton, N.H.K.
Published: 2023
A programme of Lesser Black-backed Gull Larus fuscus tagging and tracking work was initiated within the Alde-Ore Estuary Special Protection Area during the 2019 breeding season, and continued throughout the 2020 breeding season, in order to fulfil requirements of the Galloper Wind Farm Ornithological Monitoring Programme and test key predictions of the Environmental Statement. The results from both the 2019 and 2020 breeding seasons of tracking are summarised within this report.
13.07.23
Research reports Research reports
