1. Questioning the validity of the native versus alien conceptual framework:
Fred Pearce, ‘The New Wild: why invasive species will be nature’s salvation’, Icon Books Ltd, 2016.
Matthew Chew and Andrew Hamilton, ‘The Rise and Fall of Biotic Nativeness: A Historical Perspective’, in David Richardson (ed) Fifty Years of Invasion Ecology: The Legacy of Charles Elton, Blackwell Publishing Ltd, 2011.
2. Grey squirrels do not reduce the bird
Newson, et al., “Potential impact of grey squirrels (Sciurus Carolinensis) on woodland bird populations in England”, Journal of Ornithology, 2010.
3. Red squirrels decline in the 18th century, before the greys were introduced:
Harris, et al., ‘Is culling of grey squirrels a viable tactic to conserve red squirrel populations?’, Bristol University, 2008.
Middleton, The Ecology of the American Grey Squirrel in the British Isles, 1930.
4. Suitable habitat for red squirrels:
Kenward and Holm, ‘On the replacement of the red squirrel in Britain:a phytotoxic explanation.’, Proceedings of the Royal Society, Biological Sciences, 1993.
5. Greys and reds coexisting when the habitat is suitable for the reds:
Bryce et al., ‘Can niche use in red and grey squirrels offer clues for their apparent coexistence?’, Journal of Applied Ecology, 2002.
6. Reintroductions of red squirrels from Scandinavia:
Hale, et al., ‘Patterns of genetic diversity in the red squirrel (Sciurus vulgaris L.): Footprints of biogeographic history and artificial introductions.’, University of Newcastle, 2003.
7. Grey squirrels not directly responsible for the pox in red squirrels:
Chantrey et al., ‘European red squirrel population dynamics driven by squirrelpox at a gray squirrel invasion interface’, Ecology and Evolution, 2014.
Simpson et al., ‘Causes of mortality and pathological lesions observed post-mortem in res squirrels (Sciurus vulgaris) in Great Britain’, BMC Veterinary Research, 2013.
8. Culling grey squirrels an inappropriate way to help red squirrels:
Harris, et al., ‘Is culling of grey squirrels a viable tactic to conserve red squirrel populations?’, Bristol University, 2008.