John Calladine

Senior Research Ecologist

John is responsible for managing, developing and undertaking research projects relevant to Scotland, in particular the development of BTO Scotland’s portfolio of studies related to forest and moorland management.

Interests & Responsibilities

  • Direct and extensive experience of working on a range of applied conservation research and survey projects.
  • Extensive experience of interpreting survey results and reviewing for applied conservation purposes.
  • Involvement with practical land management issues and how they influence nature conservation interests.

Recent and current studies include: (i) long-term monitoring associated with moorland management; (ii) the bird communities in new native-type woodlands; (iii) bird-habitat relationships and the influence of restructuring the interface between conifer plantations and moorland and other aspects of plantation management; (iv) the development of survey methods for the monitoring of Short-eared Owls and for birds of alpine habitats in Scotland; (v) bird communities in short-rotation forestry energy crops; (vi) population changes in breeding waders on machair; (vi) reviews of the populations of predatory birds and the ecology of urban gulls in Scotland; (vii) studies on the winter ecology of some seed-eating birds; and (viii) studies on upland habitat selection by breeding Whinchats.

Other Information

An active bird ringer Honorary Lecturer in the School of Biological & Environmental Sciences, University of Stirling (since 2005)


BSc (Hons) Ecology, University of Lancaster, 1979-1982 MSc (by research) ‘Colony attendance, nest site selection and breeding performance in the Herring and Lesser Black-backed Gull: implications for conservation management’, 1993-95. Honorary Lecturer in the School of Biological & Environmental Sciences, University of Stirling (since 2005)

Recent BTO Publications

Calladine, J., Southall, C., Wetherhill, A. & Morrison, N. 2024. Use of dwarf shrubland–grassland mosaics by a nomadic predatory bird, the Short-eared Owl Asio flammeus. Journal of Ornithology Link to publication View at journal website (DOI: 10.1007/s10336-024-02174-z)
van Bemmelen, R., Moe, B., Schekkerman, H., Hanssen, S.A., Snell, K., Humphreys, L., Mäntylä, E., Hallgrimsson, G.T., Gilg, O., Ehrich, D., Calladine, J., Hammer, S., Harris, S., Lang, J., Vignisson, S., Kolbeinsson, Y., Kimmo, N., Sillanpää, M., Sittler, B., Sokolov, A., Klaassen, R., Phillips, R. & Tulp, I. 2024. Synchronous timing of return to breeding sites in a long-distance migratory seabird with ocean-scale variation in migration schedules. Movement Ecology View at journal website (DOI: 10.1186/s40462-024-00459-9)
O'Hanlon, N.J., van Bemmelen, R.S.A., Snell, K.R.S., Conway, G.J, Thaxter, C.B., Aiton, H., Aiton, D., Balmer, D.E., Are Hanssen, S., Calladine, J.R., Hammer, S., Harris, S.J., Moe, B., Schekkerman, H., Tulp, I. & Humphreys, E.M. 2024. Atlantic populations of a declining oceanic seabird have complex migrations and weak migratory connectivity to staging areas. Marine Ecology Progress Series 730 : 113-129 View at journal website (DOI: 10.3354/meps14533)
Calladine, J., Hallgrimsson, G.T., Morrison, N., Southall, C., Gunnarsson, H., Jubete, F., Sergio, F. & Mougeot, F. 2024. Remote tracking unveils intercontinental movements of nomadic Short-eared Owls Asio flammeus with implications for resource tracking by irruptive specialist predators. Ibis Link to publication View at journal website (DOI: 10.1111/ibi.13304)
Calladine, J., Fuller, R., Hodkinson, D., Franks, S. & Boyle, J. 2023. Changes in breeding wader populations of the Uist machair and adjacent habitats between 1983 and 2022. Scottish Birds 43 (part 2) : 132-140
Calladine, J., Border, J., O’Connell, P. & Wilson, M. 2022. Modelling important areas for breeding waders as a tool to target conservation and minimise conflicts with land use change. Journal for Nature Conservation Link to publication View at journal website (DOI:

Other Publications

Calladine, J. 2004. Lesser Black-backed Gull. pp 226-241 in: Mitchell, P.I, Newton, S.F., Ratcliffe, N. & Dunn, T.E. (eds) Seabird Populations of Britain and Ireland. T.& A.D. Poyser, London.

Calladine, J., Baines, D. & Warren, P. 2002. Effects of reduced grazing on population density and breeding success of black grouse Tetrao tetrix in northern England. Journal of Applied Ecology 39: 772-780.

Calladine, J., Buner, F. & Aebischer, N.J. 1999. Temporal variations in the singing activity and detection efficiency of Turtle Doves Streptopelia turtur: implications for surveying. Bird Study 46: 74-80.

Calladine, J. 1997. A comparison of Herring Gull Larus argentatus and Lesser Black-backed gull Larus fuscus nest sites: their characteristics and relationships with breeding success. Bird Study 44: 318-326.

Calladine, J. 1997. The detection efficiency of color-banded Herring Gulls Larus argentatus and Lesser Black-backed Gulls Larus fuscus at the breeding colony: practical implications for the determination of adult survival rates. Colonial Waterbirds 20: 41-46.

Calladine, J. & Harris, M.P. 1997. Intermittent breeding in the Herring Gull Larus argentatus and the Lesser Black-backed Gull Larus fuscusIbis 139: 259-263

Wanless, S., Harris, M.P., Calladine, J. & Rothery, P. 1996. Modelling responses of herring gull and lesser black-backed gull populations to reduction of reproductive output: implications for control measures. Journal of Applied Ecology 33: 1420-1432.

Calladine, J., Harris, M.P., Taylor, S. & Wanless, S. 1995. The status of the Eider on the Isle of May and other Forth islands. Scottish Birds 18: 1-10.

Harris, M.P. & Calladine, J. 1993. A check of the efficiency of finding colour-ringed Kittiwakes Rissa tridactyla Ringing and Migration 14: 13-116.

Calladine, J., Dougill, S., Harding, N. & Stroud, D.A. 1990. Moorland birds on the Campsie Fells, Touch Hills and west Ochill Hills, Stirling: Habitats, distribution and numbers. Forth Naturalist and Historian 13: 3-69.

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