Amat, J. A. and Green, A. J. (2010) Waterbirds as bioindicators of environmental conditions. Pp. 45–52 in Hurford, C., Schneider, M. and Cowx, I., eds. Conservation monitoring in freshwater habitats. Dordrecht, The Netherlands: Springer.
BirdLife International (2015) European Red List of Birds. Luxembourg: Office for Official Publications of the European Communities.
Black, J. M. and Rees, E. C. (1984) The structure and behaviour of the Whooper Swan population wintering at Caerlaverock, Dumfries and Galloway, Scotland: an introductory study. Wildfowl 35: 21–36.
Bowler, J. M. (1994) The condition of Bewick’s Swans Cygnus columbianus bewickii in winter as assessed by their abdominal profiles. Ardea 82: 241–248.
Burton, N. H., Rehfisch, M. M., Clark, N. A. and Dodd, S. G. (2006) Impacts of sudden winter habitat loss on the body condition and survival of redshank Tringa totanus. J. Appl. Ecol. 43: 464–473.
Cadbury, C. J. (1975) Populations of swans at the Ouse Washes, England. Wildfowl 26: 148–159.
Davis, J. B., Guillemain, M., Kaminski, R. M., Arzel, C., Eadie, J. M. and Rees, E. C. (2014) Habitat and resource use by waterfowl in the northern hemisphere in autumn and winter. Wildfowl Special Issue No. 4: 17–69.
Dirksen, S., Beekman, J. H. and Slagboom, T. H. (1991) Bewick’s Swans Cygnus columbianus bewickii in the Netherlands: numbers, distribution and food choice during the wintering season. Wildfowl Supplement No. 1: 228–237.
Evans, M. E. and Kear, J. (1978) Weights and measurements of Bewick’s Swans during winter. Wildfowl 29: 118–122.
Frost, T. M., Austin, G. E., Calbrade, N. A., Mellan, H. J., Hearn, R. D., Stroud, D. A., Wotton, S. R. and Balmer, D. E. (2017) Waterbirds in the UK 2015/16: The Wetland Bird Survey. Thetford, UK: British Trust for Ornithology, the Royal Society for the Protection of Birds and the Joint Nature Conservation Committee, in association with the Wildfowl and Wetlands Trust. Accessible at http://www.bto.org/volunteer-surveys/webs/publications/webs-annual-report
Hoare, J. M., Pledger, S., Keall, S. N., Nelson, N. J., Mitchell, N. J. and Daugherty, C. H. (2006) Conservation implications of a long-term decline in body condition of the Brothers Island tuatara (Sphenodon guntheri). Anim. Conserv. 9: 456–462.
Inger, R., Harrison, X. A., Ruxton, G. D., Newton, J., Colhoun, K., Gudmundsson, G. A., McElwaine, G., Pickford, M., Hodgson, D. and Bearhop, S. (2010) Carry-over effects reveal reproductive costs in a long-distance migrant. J. Anim. Ecol. 79: 974–982.
Laubek, B. (1995) Habitat use by Whooper Swans Cygnus cygnus and Bewick’s Swans Cygnus columbianus bewickii wintering in Denmark: increasing agricultural conflicts. Wildfowl 46: 8–15.
Litvin, K. and Vangeluwe, D. (2016) The Bewick’s Swan is a paradox. Swan News 12: 12.
McFadden, D. (1973) Conditional logit analysis of qualitative choice behavior. Pp. 105–142 in Zarembka, P., ed. Frontiers in econometrics. New York, USA: Academic Press.
Meek, E. R. (1993) Population fluctuations and mortality of Mute Swans on an Orkney loch system in relation to a Canadian pondweed growth cycle. Scot. Birds 17: 85–92.
Meier-Peithmann, W. (2011) Change of feeding ecology of Whooper Swan, Bewick’s Swan and Mute Swan Cygnus cygnus, C. bewickii, C. olor during the period 1965-2010 at the Dannenberger Elbbogen (N Germany). Vogelwelt 132: 57–79.
Merne, O. J. (1972) Bewick’s Swans feeding on waste potatoes and other agricultural crops. Brit. Birds 65: 394–395.
Nakagawa, S. and Schielzeth, H. (2013) A general and simple method for obtaining R 2 from generalized linear mixed-effects models. Method. Ecol. Evol. 4: 133–142.
Nagy, S., Petkov, N., Rees, E. C., Solokha, A., Hilton, G., Beekman, J. and Nolet, B. (2012) International Single Species Action Plan for the Conservation of the Northwest European Population of Bewick’s Swan (Cygnus columbianus bewickii). AEWA Technical Series No. 44. Bonn, Germany: AEWA. Accessible at http://www.unep-aewa.org/sites/default/files/publication/ts44_ssap_bewicks_swan.pdf
Newton, I. (1980) The role of food in limiting bird numbers. Ardea 68: 11–30.
Newton, I. (2013) Bird populations. London, UK: Harper Collins.
Noordhuis, R., van der Molen, D. T. and van den Berg, M. S. (2002) Response of herbivorous water-birds to the return of Chara in Lake Veluwemeer, The Netherlands. Aquat. Bot. 72: 349–367.
Owen, M. and Cadbury, C. J. (1975) The ecology and mortality of swans at the Ouse Washes, England. Wildfowl 26: 31–42.
Owen, M. and Kear, J. (1972) Food and feeding habits of swans. Pp. 58–77 in Scott, P. and The Wildfowl Trust, eds. The swans. London, UK: Michael Joseph.
Owen, M., Wells, R. L. and Black, J. M. (1992) Energy budgets of wintering barnacle geese: the effects of declining food resources. Ornis Scand. 23: 451–458.
Peig, J. and Green, A. J. (2009) New perspectives for estimating body condition from mass/length data: the scaled mass index as an alternative method. Oikos 118: 1863–1891.
Pinheiro, J., Bates, D., DebRoy, S., Sarkar, D. and R Core Team (2017) nlme: Linear and nonlinear mixed effects models. R package version 3.1-131. Accessible at https://CRAN.R-project.org/package=nlme.
Ponting, J. (2014) Factors affecting the feeding distribution of Bewick’s (Cygnus columbianus bewickii) and Whooper (Cygnus cygnus) Swans wintering on the Ouse Washes, Norfolk. BSc. Thesis. Cardiff, UK: Cardiff University, School of Biosciences.
Poorter, E. P. R. (1991) Bewick’s Swans Cygnus columbianus bewickii, an analysis of breeding success and changing resources. Lelystad, the Netherlands: Ministerie van Verkeer en Waterstaat, Rijkswaterstaat, Directie Flevoland.
R Development Core Team (2018) R: a language and environment for statistical computing. [3.5.1]. Vienna, Austria: R Foundation for Statistical Computing. Accessible at http://www.R-project.org/
Rees, E. C. (2006) Bewick’s swan. London, UK: T. and A. D. Poyser.
Rees, E. C. and Beekman, J. H. (2010) Northwest European Bewick’s Swans: a population in decline. Br. Birds 103: 640–650.
Rees, E. C., Kirby, J. S. and Gilburn, A. (1997) Site selection by swans wintering in Britain and Ireland; the importance of habitat and geographic location. Ibis 139: 337–352.
Richards, S. A., Whittingham, M. J. and Stephens, P. A. (2011) Model selection and model averaging in behavioural ecology: the utility of the IT-AIC framework. Behav. Ecol. Sociobiol. 65: 77–89.
Scott, D. K. (1978) Social behaviour of wintering Bewick’s Swans. PhD thesis. Cambridge, UK: University of Cambridge.
Sherry, T. W., Johnson, M. D. and Strong, A. M. (2005) Does winter food limit populations of migratory birds. Pp. 414–425 in Greenberg, R. and Marra, P. P., eds. Birds of two worlds: The ecology and evolution of migration. Baltimore, USA: Johns Hopkins University Press.
Siriwardena, G. M., Calbrade, N. A. and Vickery, J. A. (2008) Farmland birds and late winter food: does seed supply fail to meet demand? Ibis 150: 585–595.
Stillman, R. A., Wood, K. A., Gilkerson, W., Elkinton, E., Black, J. M., Ward, D. H. and Petrie, M. (2015) Predicting effects of environmental change on a migratory herbivore. Ecosphere 6: art. 114.
Tijsen, W. and Koffijberg, K. (2015) Thirty years of goose and swan counts in the north of the province of Noord-Holland. Limosa 88: 83–95.
van Gils, J. A. and Tijsen, W. (2007) Short-term foraging costs and long-term fueling rates in central-place foraging swans revealed by giving-up exploitation times. Am. Nat. 169: 609–620.
Wahl, J. and Degen, A. (2009) Rastbestand und Verbreitung von Singschwan Cygnus cygnus und Zwergschwan C. bewickii im Winter 2004/05 in Deutschland. Vogelwelt 130: 1–24.
Warton, D. I., Duursma, R. A., Falster, D. S. and Taskinen, S. (2012) smatr 3 – an R package for estimation and inference about allometric lines. Method. Ecol. Evol. 3: 257–259. Accessible at https://CRAN.R-project.org/package=smatr
Wood, K. A., Newth, J. L., Hilton, G. M., Nolet, B. A. and Rees, E. C. (2016) Inter-annual variability and long-term trends in breeding success in a declining population of migratory swans. J. Avian Biol. 47: 597–609.
Wood, K. A., Nuijten, R. J. M., Newth, J. L., Haitjema, T., Vangeluwe, D., Ioannidis, P., Harrison, A. L., Mackenzie, C., Hilton, G. M., Nolet, B. A. and Rees, E. C. (2018a) Apparent survival of an Arctic breeding migratory bird over 44 years of fluctuating population size. Ibis 160: 413–430.
Wood, K. A., Newth, J. L., Hilton, G. M. and Rees, E. C. (2018b) Has winter body condition varied with population size in a long-distance migrant, the Bewick’s Swan (Cygnus columbianus bewickii)? Eur. J. Wildlife Res. 64: 38.