About me

I began life at WWT as a student in 1993, conducting a breeding bird survey of the Cotswold Water Park. This was in part to also facilitate planning for a student expedition to Argentina to search for Brazilian Merganser, in which I participated in June – October 1993. Soon after I returned to work for WWT on Ruddy Ducks and Pink-footed Geese in 1994-95 before getting a full-time post as Ringing Assistant in 1995.

Since then I have worked on a range of waterbird conservation projects, with a focus on population monitoring. Current priorities include Baer’s Pochard conservation, waterbird monitoring in East Asia, conservation and monitoring of European seaducks, and goose and swan monitoring and management in the UK.


My role since 2006 has been Head of Monitoring Unit in the Conservation Science Department at WWT. I am responsible for the delivery and development of waterbird monitoring activities. This encompasses three core work areas: Integrated Waterbird Monitoring, Capacity Building for Waterbird Monitoring, and Indicators & Assessments. All of these work areas and projects are focused on two priority regions: Northwest Europe and East Asia.

I also represent, or have represented, WWT on a number of relevant bodies: African-Eurasian Waterbird Monitoring Partnership Strategic Working Group, Wetland Bird Survey Steering Committee, Goose & Swan Monitoring Partnership Steering Group, UK Avian Population Estimates Panel, SPA/Ramsar Scientific Working Group, Defra’s Hunting Bag Statistics Working Group, Defra’s Brent Goose Management Review Group, BTO Cannon-netting Technical Panel, and inputs to the production of outputs such as Birds of Conservation Concern, State of the UK’s Birds, and Waterbird Population Estimates.

I have contributed to a number of training courses in monitoring techniques, primarily in China but also Nigeria, Kenya, Botswana, Georgia and Azerbaijan, and through courses for international delegates held at WWT Slimbridge.

I also coordinate two expert groups tasked with overseeing the implementation of species action plans – the EAAFP Baer’s Pochard Task Force and the AEWA European Seaduck International Working Group (who focus on Long-tailed Duck and Velvet Scoter).

I have also been the Chair of the IUCN-SSC/Wetlands International Duck Specialist Group since 2010.


I have over 15 years’ experience in the design, implementation, data analysis and reporting of waterbird monitoring activities, such as counts (including the coordination of large volunteer-based surveys), assessments of breeding success, maintenance of marked populations, and observations of individual birds.

I have extensive fieldwork experience with waterbirds, particularly wildfowl and shorebirds, including surveys and ringing. I have held a UK ringing licence since 1988 and a cannon-netting licence since 1997.


Brides, K., K.A. Wood, R.D. Hearn & T.P.M. Fijen. 2017. Changes in the sex ratio of the Common Pochard Aythya ferina in Europe and North Africa. Wildfowl 67: 100-112.

Eaton, M.A., N.J. Aebischer, A.F. Brown, R.D. Hearn, L. Lock, A.J. Musgrove, D.G. Noble, D.A. Stroud & R.D. Gregory. 2015. Birds of Conservation Concern 4: the population status of birds in the United Kingdom, Channel Islands and the Isle of Man. British Birds 108: 708-746.

Frederiksen, M., R.D. Hearn, C.R. Mitchell, A.Þ. Sigfússon, R.L. Swann & A.D. Fox. 2004. The size and dynamics of Icelandic-breeding goose populations: a reassessment of the evidence. Journal of Applied Ecology 41: 315-334.

Guillemain, M., C. Calenge, J. Champagnon & R.D. Hearn. 2017. Determining the boundaries and plasticity of migratory bird flyways: a Bayesian model for Eurasian Teal Anas crecca in Western Europe. Journal of Avian Biology.

Guillemain, M., O. Devineau, M. Gauthier-Clerc, R.D. Hearn, R. King, G. Simon & M. Grantham. 2011. Changes in ring recovery rates over the last 50 years: shall we continue to ring ducks? Journal of Ornithology 152: 55-61.

Guillemain, M., J. Elmberg, M. Gauthier-Clerc, G. Massez, R.D. Hearn, J. Champagnon & G. Simon. 2010. Wintering French Mallard and Teal are heavier and in better body condition than 30 years ago: effects of a changing environment? Ambio 39: 170-180.

Guillemain, M. & R.D. Hearn. 2017. Ready for climate change? Geographic trends in the protection status of Critical Sites for Western Palearctic ducks. Biodiversity and Conservation 26: 2347-2360.

Guillemain, M., R.D. Hearn, R. King, M. Gauthier-Clerc, G. Simon & A. Caizergues. 2009. Comparing the migration of Eurasian Teal Anas crecca from two main wintering areas of Western Europe: a long-term study from Essex, England, and the Camargue, France. Ringing & Migration 24: 273-276.

Hearn, R.D. 2015. International Single Species Action Plan for the Conservation of the Baer’s Pochard (Aythya baeri), 2015-2019. CMS Technical Series No. 37. EAAFP.

Hearn, R.D. 2015. The troubled Baer’s Pochard Aythya baeri: cause for a little optimism? BirdingASIA 24: 78–83.

Hearn, R.D., A.L. Harrison & P.A. Cranswick. 2015. International Single Species Action Plan for the conservation of the Long-tailed Duck Clangula hyemalis, 2016–2025. AEWA Technical Series.

Kershaw, M., R.D. Hearn & P.A. Cranswick. 2001. The role of ringing in integrated population monitoring of Anatidae in the United Kingdom. Ardea 89(1):209-220.

Lehikoinen, A., K. Jaatinen, A. Vähätalo, P. Clausen, O. Crowe, B. Deceuninck, R.D. Hearn, C.A. Holt, M. Hornman, V. Keller, L. Nilsson, T. Langendoen, I. Tománková, J. Wahl & A.D. Fox. 2013. Rapid climate driven shifts in wintering distributions of three common waterbird species. Global Change Biology 19: 2071-2081.

Madsen, J., N. Bunnefeld, S. Nagy, C. Griffin, P. Defos du Rau, J.-Y. Mondain-Monval, R.D. Hearn, A. Czajkowski, A. Grauer, F.R. Merkel, J.H. Williams, M. Alhainen, M. Guillemain, A. Middleton, T.K. Christensen & O. Noe. 2015. Guidelines on Sustainable Harvest of Migratory Waterbirds. AEWA Conservation Guidelines No. 5, AEWA Technical Series No. 62. Bonn, Germany.

Mitchell, C., R.D. Hearn & D.A. Stroud. 2012. The merging of populations of Greylag Geese breeding in Britain. British Birds 105: 498-505.

Musgrove, A.J., N.J. Aebischer, M.A. Eaton, R.D. Hearn, S.E. Newson, D.G. Noble, M. Parsons, K. Risely & D.A. Stroud. 2013. Population estimates of birds in Great Britain and the United Kingdom. British Birds 106: 64-100.

Musgrove, A.J., G.E. Austin, R.D. Hearn, C.A. Holt, D.A. Stroud & S.R. Wotton. 2011. Overwinter population estimates of British waterbirds. British Birds 104: 364-397.

Patterson, I.J. & R.D. Hearn. 2006. Turnover of individuals in a local population of Pink-footed Geese Anser brachyrhynchus. Wildfowl 56: 52-64.

Patterson, I.J. & R.D. Hearn. 2006. Month to month changes in age ratio and brood size in Pink-footed Geese Anser brachyrhynchus in autumn. Ardea 94: 175-183.

Pavon-Jordan, D., A.D. Fox, P. Clausen, M. Dagys, B. Deceuninck, K. Devos, R.D. Hearn, C.A. Holt, M. Hornman, V. Keller, T. Langendoen, Ł. Ławicki, S.H. Lorentsen, L. Luigujoe, W. Meissner, P. Musil, L. Nilsson, J.-Y. Paquet, A. Stipniece, D.A. Stroud, J. Wahl, M. Zenatello & A. Lehikoinen. 2015. Climate-driven changes in winter abundance of a migratory waterbird in relation to EU protected areas. Diversity and Distributions (2015): 1–12.

Peng, H., G.Q.A. Anderson, Q. Chang, C. Choi, S.U. Chowdhury, N.A. Clark, X. Gan, R.D. Hearn, J. Li, E.G. Lappo, W. Liu, Z. Ma, D.S. Melville, J.F. Phillips, E.E. Syroechkovskiy, M. Tong, S. Wang, L. Zhang & C. Zockler. 2017. The intertidal wetlands of southern Jiangsu Province, China – globally important for Spoon-billed Sandpipers and other threatened waterbirds, but facing multiple serious threats. Bird Conservation International: 1-18.

Stanbury, A.J., A. Brown, M.A. Eaton, N.J. Aebischer, S. Gillings, R.D. Hearn, D.G. Noble, D.A. Stroud & R.D. Gregory. 2017. The risk of extinction for birds in Great Britain. British Birds 110: 502-517.

Swann, R.L., I.K. Brockway, M. Frederiksen, R.D. Hearn, C. Mitchell & A. Sigfússon. 2005. Within-winter movements and site fidelity of Icelandic Greylag Geese Anser anser. Bird Study 52: 25-36.

Tao, X., J. Lei, R.D. Hearn & G. Lei. 2017. Report on the coordinated survey for wintering waterbirds of the Central and Lower Yangtze in 2015. WWF China, Wuhan.