Stephen Baillie

Stephen Baillie


Senior Research Fellow


To undertake, develop and supervise research on processes determining avian distributions and abundances, from local to continental scales, primarily using high quality citizen science data colleced by BTO and smilar oganisations.  I have particular interests in population dynamics and in studies of year-round abundance, migration routes and phenology.


BSc (Hons) Zoology, University of Aberdeen, 1972-76
PhD, Population dynamics of the Eider (Somateria mollissima) in North-East Scotland, University of Aberdeen, 1976-1980

Other information

Honorary Reader in Biological Sciences, University of East Anglia
Chair of European Union for Bird Ringing (EURING) Atlas Committee
Member of EuroBirdPortal steering group
Researcher at BTO since 1980
Former BTO Director of Science (1987-2014), during which time I led the establishment of the Breeding Bird Survey and BirdTrack, the scientific development of demographic monitoring (Ringing, Nest Records, Constant Effort Sites, Retrapping Adutls for Survival) and BTO's use of the internet to gather scientific data and disseminate the results.

Research Interests/Responsibilities

Patterns of avian abundance arise from variation in reproductive rates and survival, and at smaller scales also from dispersal.  I have had a long term involvement in the development of BTO's Integrated Population Monitoring Programme, where we use our volunteer-based demographic monitoring schemes to provide measures of breeding success and survival for a wide range of species (for current trends see  My current work focusses on the use of Integrated Population Models to understand these demographic processes within a coherent statistical framework.  I am interested in the ways in which environmental conditions and competitive interactions (density-dependence) interact to determine large-scale abundance patterns.  A second major research interest is the use of Citizen Science data to study year-round patterns of occurence, abundance, migration and phenology at national and continental scales.  This research involves leading analyses of BirdTrack data and collaboration with European colleagues to develop a continental approach through the EuroBirdPortal project, which is bringing together similar datasets from across Europe.  I lead BTO's input to EuroBirdPortal which will soon deliver close to real tme continental-scale outputs.  In a related initiative I am working with colleagues in EURING to develop a European Migration Atlas based on ring recoveries and tracking data.  This will be based on data from the EURING databank which is hosted by BTO.  Tracking technologies are rapidly advancing our knowledge of avian movement patterns.  I am collaborating with BTO volunteer, Graham Geen, on an extensive review of tracking studies to evaluate their potential impacts on birds and as an input to the European Migration Atlas.  Large-scale studies of avian ecology offer opportunities for substantial advances in our understanding of year-round patterns of avian occurence and abundance and of the demographic processes that underpin them. Such knowledge is essential for increasing our understanding of the impacts of environmental and climate change, and how these can best be managed. 

Current Research Student

Marina Jiminez-Munoz, School of Mathematics, Statistics and Actuarial Science, University of Kent. Co-supervised with Drs Diana Cole, Eleni Matechou and Rob Robinson.  Research project on spatially explicit integrated population models.

Selected Publications

  • du Feu, C.R. Clark, J.A., Schaub, M., Fiedler, W. & Baillie, S.R. (2016) The EURING Data Bank – a critical tool for continental-scale studies of marked birds, Ringing & Migration, 31:1, 1-18.
  • Johnston, A., Robinson, R.A., Gargallo, G., Julliard R., Van Der Jeugd, H. & Baillie, S.R. (2016) Survival of Afro-Palaearctic passerine migrants in western Europe and the impacts of seasonal weather variables. Ibis. DOI: 10.1111/ibi.12366.
  • Newson, S.E., Moran, N.J., Musgrove, A.J., Pearce-Higgins, J.W., Gillings, S., Atkinson, P.W., Miller, R., Grantham, M.J. and Baillie, S.R. 2016. Long-term changes in the migration phenology of UK breeding birds detected by large-scale citizen science recording schemes. Ibis 158 (3): 481-495.
  • Eglingon, S.M., Julliard, R., Gargallo, G, Jeugd, H.P., Pearce-Higgins, J.W.,  Baillie, S.R. & Robinson, R.A. (2015). Latitudinal gradients in the productivity of European migrant warbers have not shifted northwards during a period of climate change.  Global Ecology and Biogeography 24 (4), 427-436.
  • Morrison, C.A., Baillie, S.R., Clark, J.A., Johnston, A., Leech, D.I. & Robinson, R.A. (2015).  Flexibility in the timing of post-breeding moult in passerines in the UK. Ibis 157 (2), 340-350.
  • Ockendon, N., Johnston, A., & Baillie, S. R. (2015). Rainfall on wintering grounds affects population change in many species of Afro-Palaearctic migrants. Journal of Ornithology 155 (4), 905-917.
  • Ambrosini, R., Borgoni, R., Rubolini, D., Sicurell, B., Fiedler, W., Bairlein, F., Baillie, S.R., Robinson, R.A., Clark, J.A., Spina, F. & Saino, N. (2014). Modelling the Progression of Bird Migration with Conditional Autoregressive Models Applied to Ringing Data. PLos ONE 9 (7): e102440. DOI: 10.1371/journal.pone.0102440.
  • Johnston, A., Newson, S.E., Risely, K., Musgrove, A.J., Massimino,D., Baillie, S.R. & Pearce-Higgins, J.W. (2014). Species traits explain variation in detectability of UK birds. Bird Study 61 (3), 340-350.
  • Robinson, R. A., Morrison, C. A., & Baillie, S. R. (2014). Integrating demographic data: towards a framework for monitoring wildlife populations at large spatial scales. Methods in Ecology and Evolution 5 (12) 1361-1372.
  • Siriwardena, G. M., Baillie, S.R., Fuller, R.F. & Robinson, R.A. (2014). How can functional space for farmland birds best be studied? A comment on Butler and Norris (2013).  Agriculture Ecosystems & Environment 192, 8-11.
  • Thorup, K., Korner-Nievergelt, F., Cohen, E.B. & Baillie, S.R. (2014). Large-scale spatial analysis of ringing and re-encounter data to infer movement patterns: A review including methodological perspectives.  Methods in Ecology and Evolution 5 (12), 1361-1372.
  • Newson, S. E., Massimino, D., Johnston, A., Baillie, S. R., & Pearce-Higgins, J. W. (2013). Should we account for detectability in population trends?. Bird Study, 60 (3), 384-390.
  • Buckland, S.T.,  Baillie, S.R., Dick, J. McP., Elston, D.A., Magurran, A.E., Scott, E.M., Smith, R.I., Somerfield, P.J., Studeny, A.C. and Watt, A. (2012). How should regional biodiversity be monitored?  Environmental and Ecological Statistics, 19, 601-626.
  • Newson, S.E., Johnston, A., Renwick, A.R., Baillie, S.R. & Fuller, R.J. (2012). Modelling large-scale relationships between changes in woodland deer and bird populations.  Journal of Applied Ecology, 49, 278-286.
  • Robinson, R.A., Baillie, S.R. & King, R. (2012). Population processes in European Blackbirds Turdus merula : a state-space approach. Journal of Ornithology, 152, Supplement 2, 419-433.
  • Furness, R.W., Mable, B., Savory, F., Griffiths, K., Baillie, S.R. & Heubeck, M. (2010). Subspecies status of Common Eiders Somateria mollissima in Shetland based on morphology and DNA. Bird Study 57, 330-335.
  • Magurran, A.E., Baillie, S.R., Buckland, S.T., Dick, J. McP., Elston, D.A., Scott, E.M., Smith, R.I., Somerfield, P.J. & Watt, A.D. (2010). Long-term datasets in biodiversity research and monitoring: assessing change in ecological communities through time. Trends in Ecology and Evolution 25: 574-582.
  • Newson, S.E., Rexstad, E.A., Baillie, S.R., Buckland, S.T. & Aebischer, N.J. (2010). Population change of avian predators and grey squirrels in England: is there evidence for an impact on avian prey populations? Journal of Applied Ecology 47: 244-252. 
  • Thaxter, C.B., Joys, A.C., Gregory, R.D., Baillie, S.R. & Noble, D.G. (2010). Hypotheses to explain patterns of population change among breeding bird species in England. Biological Conservation 143, 2006-2019.
  • Baillie, S.R. & Schaub, M. (2009). Understanding changes in bird populations – the role of bird marking. Ringing & Migration 24, 189-198.
  • Baillie, S.R., Robinson, R.A., Clark, J.A. & Redfern, C.P.F. (2009). From individuals to flyways: the future of marking birds for conservation. Ringing & Migration 24, 155-161.
  • Newson, S.E., Ockendon, N., Joys, A., Noble, D.G. & Baillie, S.R. (2009). Comparison of habitat-specific trends in the abundance of breeding birds in the UK. Bird Study 56, 233-243.
  • Freeman, S.N., Noble, D.G., Newson, S.E. & Baillie, S.R. (2007) Modelling population changes using data from different surveys: the Common Birds Census and the Breeding Bird Survey. Bird Study 54, 61-72.
  • Baillie, S.R., Balmer, D.E., Downie, I.S. & Wright, K.H.M. (2006). Migration Watch – an Internet survey to monitor spring migration in Britain and Ireland. Journal of Ornithology, 147, 254-259.
  • Newson, S.E., Woodburn, R.J.W., Noble, D.G., Baillie, S.R. & Gregory, R. D. (2005). Evaluating the Breeding Bird Survey for producing national population size and density estimates. Bird Study, 52, 42-54.
  • Gregory, R.D. & Baillie, S.R. (2004)  Survey design and sampling strategies for breeding bird monitoring.  In: Anselin, A. (ed.) Bird Numbers 1995, Proceedings of the International Conference and 13th Meeting of the European Bird Census Council, Pärnu, Estonia. Bird Census News 13 (2000): 19-31.
  • Gregory, R.D., Baillie, S.R. & Bashford, R.I. (2004)  Monitoring breeding bird in the United Kingdom.  In: Anselin, A. (ed.) Bird Numbers 1995, Proceedings of the International Conference and 13th Meeting of the European Bird Census Council, Pärnu, Estonia . Bird Census News 13 (2000): 101-112.
  • Baillie, S.R. & Doherty, P.F.Jr. (2004). Analysis using large-scale ringing data. Animal Biodiversity and Conservation, 27, 371-373.
  • Robinson, R.A., Green, R.E., Baillie, S.R., Peach, W.J. & Thomson, D.L. (2004) Demographic mechanisims of the population decline of the song thrush Turdus philomelos in Britain. Journal of Animal Ecology 73, 670-682.
  • Siriwardena, G.M., Wernham, C.V. & Baillie, S.R. (2004). Quantifying variation in migratory strategies using ring-recoveries. Animal Biodiversity and Conservation, 27, 299-317.
  • Peach, W.J. & Baillie, S.R. (2004). Estimating adult survival rates from between-year recaptures in the British Trust for Ornithology Constant Effort Sites Scheme. Studies in Avian Biology, 29, 71-74.
  • Robinson, R.A., Green, R.E., Baillie, S.R., Peach, W.J. & Thomson, D.L. (2004). Demographic mechanisms of the population decline of the song thrush Turdus philomelos in Britain. Journal of Animal Ecology, 73, 670-682.
  • Wernham, C.V., Toms, M.P., Marchant, J.H., Clark, J.A., Siriwardena, G.M. & Baillie, S.R. (eds.) (2002). The Migration Atlas: movements of the birds of Britain and Ireland. T. & A.D. Poyser, London.
  • Baillie, S.R. (2001). The contribution of ringing to the conservation and management of bird populations: a review. Ardea, 89 (special issue), 167-184.
  • Baillie, S.R., Sutherland, W.J., Freeman, S.N., Gregory, R.D. & Paradis, E. (2000). Consequences of large-scale processes for the conservation of bird populations. Journal of Applied Ecology, 37, (supplement 1), 88-102.
  • Fewster, R.M., Buckland, S.T., Siriwardena, G.M., Baillie, S.R. & Wilson, J.D. (2000). Analysis of population trends for farmland birds using generalized additive models. Ecology, 81, 1970-1984.
  • Paradis, E., Baillie, S.R., Sutherland, W.J. & Gregory, R.D. (2000). Spatial synchrony in populations of birds: effects of habitat, population trend and spatial ecology. Ecology, 81, 2112-2125.
  • Siriwardena, G.M., Baillie, S.R., Crick, H.Q.P. & Wilson, J.D. (2000). The importance of variation in the nesting success of seed-eating birds in determining their population trends on farmland. Journal of Applied Ecology, 37, 128-148.
  • Paradis, E., Baillie, S.R., Sutherland, W.J. & Gregory, R.D. (1999). Dispersal and spatial scale affect synchrony in spatial population dynamics. Ecology Letters, 2, 114-120.
  • Baillie, S.R. & North, P.M. (eds.) (1999). Large-scale studies of marked birds. Proceedings of EURING 97 Conference. Bird Study, 46 (supplement).
  • Gregory, R.D. & Baillie, S.R. (1998). Large-scale habitat use of a group of declining British birds. Journal of Applied Ecology, 35, 785-799.
  • Paradis, E., Baillie, S.R., Sutherland, W.J. & Gregory, R.D. (1998). Patterns of natal and breeding dispersal in birds. Journal of Animal Ecology, 67, 518-536.
  • Siriwardena, G.M., Baillie, S.R., Buckland, S.T., Fewster, R.M., Marchant, J.H. & Wilson, J.D. (1998). Trends in the abundance of farmland birds: a quantitative comparison of smoothed Common Birds Census indices. Journal of Applied Ecology, 35, 24-43.
  • Baillie, S.R. (1995). Uses of ringing data for the conservation and management of bird populations - a ringing scheme perspective. Journal of Applied Statistics, 22, 967-987.
  • Peach, W.J., Baillie, S.R. & Underhill, L.G. (1991). Survival of British Sedge Warblers Acrocephalus schoenobaenus in relation to west African rainfall. Ibis, 133, 300-305.
  • Baillie, S.R. (1990). Integrated population monitoring of breeding birds in Britain and Ireland. Ibis, 132, 151-166.

Contact details

Email: stephen.baillie [at]
Twitter: @stephenrbaillie
Google Scholar:
Telephone: 01842 750050
Fax: 01842 750030
Postal address: British Trust for Ornithology, The Nunnery, Thetford, IP24 2PU, UK.