Head & Principal Ecologist

Gavin leads the BTO’s Terrestrial Ecology team, which currently comprises up to 15 analytical and field research staff, conducting and supervising pure and applied research on terrestrial bird ecology.
Terrestrial bird ecology at a range of spatial scales, from territories to landscapes, via field experiments and analyses of large-scale, long-term datasets. Research at the BTO has considered migration ecology, cause of decline in woodland birds and methods of population trend analysis, but has focused primarily on farmland birds, contributing directly to government policy on the environment.
A major three-year project on the demography of farmland birds (1996-1999), involving detailed analyses of extensive data sets held by the BTO and other organizations, helped to identify causes of decline. Subsequent large-scale projects have tested the hypotheses identified using landscape-scale field experiments and have also considered the likely efficacy of management solutions (2001-2007).
More recently, research has focused on testing the agri-environment solutions to farmland bird conservation problems and on measuring the effects of current issues in farmland such as the disappearance of set-aside. A parallel research direction is considering bird-habitat modelling, considering both habitat types per se and habitat heterogeneity.
Planned future research directions include further work on heterogeneity and habitat interactions, the ecology of predation and the design and testing of agri-environment solutions to the farmland bird conservation problems that still remain.
Other Information
Member of the Editorial Board of Bird Study. Member of the British Ornithologists’ Union’s council.
BA Natural Sciences (Zoology), University of Cambridge 1990 PhD Aspects of Vocal Communication in the Carrion Crow, University of Leicester 1995
Recent BTO Publications
- Macgregor, C.J., Pearce-Higgins, J.W., Siriwardena, G.M., Wilson, M.W. & Robinson, R.A. 2025. Assessment of recent Hen Harrier population trends in England through population modelling. BTO Research Report 774:
- Hawkes, R.W., Mason, L.R., Conway, G.J., Siriwardena, G.M., Grice, P.V., Cole, A.J. & Peach, W.J. 2025. Landscape context influences efficacy of protected areas and agri-environment scheme delivery for breeding waders. Journal of Applied Ecology 62: 1114-1126 doi:10.1111/1365-2664.70039
- Pirzio-Biroli, A., Crowley, S.L., Siriwardena, G.M., Plummer, K.E., Schroeder, J. & White, R.L. 2024. Not in the countryside please! Investigating UK residents’ perceptions of an introduced species, the ring-necked parakeet (<em>Psittacula krameri</em>). NeoBiota 93: 1-24 doi:10.3897/neobiota.93.110122
- Bateman, I.J., Binner, A. Addicott, E.T., Balmford, B., Cho F.H.T., Daily, G.C., De-Gol, A., Eisenbarth, S., Faccioli, M., Ferguson-Gow, H., Ferrini, S., Fezzi, C., Gannon, K., Groom, B., Harper, A.B., Harwood, A., Hillier, J., Hulme, M.F., Lee, C.F., Liuzzo, L., Lovett, A., Mancini, M.C., Matthews, R., Morison, J.I.L., Owen, N., Pearson, R.G., Polasky, S., Siriwardena, G., Smith, P., Snowdon, P.P., Tippett, P., Vetter, S.H., Vinjili, S., Vossler, C.A., Watson, R.T., Williamson, D. & Day, B.H. 2024. How to make land use policy decisions: Integrating science and economics to deliver connected climate, biodiversity, and food objectives. Proceedings of the National Academy of Sciences 121: doi:10.1073/pnas.2407961121
- Groh, C., Siriwardena, G.M. & McMahon, B.J. 2024. Diversity in Irish and British avifauna assemblages: What can variation in diversity profiles reveal about the forces that drive assemblage composition and structure?. Ecology and Evolution 14: doi:10.1002/ece3.70143
- Cooper, J.E.J., Plummer, K.E., Middlebrook, I. & Siriwardena, G.M. 2024. Using butterfly survey data to model habitat associations in urban developments. Journal of Applied Ecology 61: 773-783 doi:10.1111/1365-2664.14583
- Boetzl, F.A., Sponsler, D., Albrecht, M., Batáry, P., Birkhofer, K., Knapp, M., Krauss, J., Maas, B., Martin, E.A., Sirami, C., Sutter, L., Bertrand, C., Bosem Baillod, A., Bota, G., Bretagnolle, V., Brotons, L., Frank, T., Fusser, M., Giralt, D., González, E., Hof, A.R., Luka, H., Marrec, R., Nash, M.A., Ng, K., Plantegenest, M., Poulin, B., Siriwardena, G.M., Tscharntke, T., Tschumi, M., Vialatte, A., Van Vooren, L., Zubair-Anjum, M., Entling, M.H., Steffan-Dewenter, I. & Schirmel, J. 2024. Distance functions of carabids in crop fields depend on functional traits, crop type and adjacent habitat: a synthesis. Proceedings of the Royal Society B: Biological Sciences 291: doi:10.1098/rspb.2023.2383
- Barton, M.G., Henderson, I., Border, J.A. & Siriwardena, G.M. 2023. A review of the impacts of air pollution on terrestrial birds. Science of The Total Environment 873: doi:10.1016/j.scitotenv.2023.162136
- Cooper, J.E.J., Plummer, K.E. & Siriwardena, G.M. 2023. Using species-habitat models to predict bird counts from urban development plans. Landscape and Urban Planning 230: doi:10.1016/j.landurbplan.2022.104629
- Plummer, K.E., Dadam, D., Brereton, T., Dennis, E.B., Massimino, D., Risely, K., Siriwardena, G.M. & Toms, M.P. 2023. Trends in butterfly populations in UK gardens – new evidence from citizen science monitoring. Insect Conservation and Diversity 17: 345-357 doi:10.1111/icad.12645