By chance, my review paper of Pheasant impacts was published at the same time as a BTO study to which I refer in the British Birds article: Pringle, H., Wilson, M., Calladine, J. & Siriwardena, G.M. (2019). Associations between gamebird releases and general predators. Journal of Applied Ecology.
Pringle et al. add another piece of evidence to the narrative that releasing 43 million Pheasants into the countryside each year has ecological impacts which government should look at. Previous work has shown that the UK has high densities of generalist predators and scavengers such as Red Foxes and Carrion Crows compared with other European countries. We also have a lot more Pheasants living and dying in the countryside, and dead Pheasants feed those generalist predators.
The BTO study shows that the comparison between the UK and the rest of Europe holds true within the UK too – places with loads of released Pheasants have higher densities of avian scavengers and predators.
I see that in the Guardian article last week, which covered both the BTO paper and my review paper, Jonathan Reynolds, head of predation control studies at GWCT, is quoted as saying of the BTO paper, ‘This study reports correlations only (ie not cause and effect) and they are very weak. We endorse the recommendation in the paper for more detailed and incisive research that looks at the hypotheses properly.‘.
Scientist says ‘more research needed’ shock! And just a quick pedantic point, when Jonathan Reynolds is quoted as saying ‘not cause and effect’ that is a bit misleading isn’t it? He might mean that correlations do not prove cause and effect (because they don’t) but he knows full well that the absence of correlations would be evidence against any cause/effect relationship and so the presence of correlations is evidence for cause and effect.
Presumably GWCT will be calling for an experimental approach to look at this question in more detail which ceases all Pheasant releases in large areas of the country for many years to see what happens compared with control regions? They will, won’t they?
GWCT have alluded to the possibility of increased predator numbers being caused by high Pheasant release numbers on their website but when more supportive evidence is added they have to downplay it because it would be very embarrassing for GWCT members and supporters if all those Pheasants and Red-legged Partridges were causing the high densities of Carrion Crows that GWCT members and supporters then had to kill under the general licences to protect Pheasants masquerading as livestock, wouldn’t it?
My BB Pheasant article puts it like this ‘Who should investigate the issues? The GWCT might seem the obvious organisation but has so far proved unwilling to tackle the most difficult issues, perhaps through fear that the information revealed might be akin to shooting its own funders in the foot.‘.