The effects of released gamebirds and their managementSubmitted by editor on 15 October 2020.
By Dr Rufus Sage
Releasing pheasants and red-legged partridges for shooting is more common in the UK than in other European countries. Conservation NGOs like the GWCT and the RSPB, and GOs like Natural England are interested in the ecological consequences of this activity. There has been a reasonable amount of research by various organisations and the GWCT has maintained a bibliography of published and unpublished material over the years. This was strengthened by a formal literature search process undertaken for a review report commissioned by Natural England earlier in 2020 by Joah Madden at Exeter University and myself.
The paper in Wildlife Biology provides a summary of effects, a simple numerical synthesis and there is an unpublished online appendix providing more details. The paper uses the literature itself to define topics and then attaches a simple categorisation to each (positive, neutral or negative). It avoids weighting or ranking them based on the number of papers or by an assessment of importance which can introduce an element of subjectivity.
Broadly speaking management of habitats for releases in and around woodlands, and planting game crops and maintaining field margins on farmland, tends to improve those habitats for a range of other wildlife. The birds themselves tend to cause negative effects on local ground flora, soils and some invertebrates, especially where pheasant releases take place in woodlands. The paper highlights more complicated indirect issues as well, such as the potential effect of gamebird releases on predator populations, and illegal killing of birds of prey. The first of these is not yet well enough understood for conclusions to be drawn and the extent to which raptors are killed alongside releasing is unclear, but any cases have a clear negative effect. Contributing factors such as the size of releases, or the scale at which an effect might operate are identified.
Pheasants in a rearing facility just before release into an open topped release pen in woodland
The approach used resulted in a very approximate balance of negative and positive/neutral effects of releasing. There are clear knowledge gaps and I anticipate a push for new research to address some of these in the near future. A key issue is the fact that numbers released in the UK have steadily increased for 50 years now (probably not in 2020!) and the suggestion is being made that they have reached unsustainable levels. On the other hand, it is clear that larger shoots have the resources to do some large scale and valuable management work in woodlands and on farmland that benefits a range of wildlife species.
It is important to remember the wider context in which these findings sit – all modern economic land-use activities in our intensively farmed and densely populated country tend to have negative ecological effects associated with them, and some have few if any positive ones. Releasing and shooting also has clear economic and social benefits (which the paper doesn’t go in to). The GWCTs approach is to publish a wide range of research-based good practice guidelines, provide courses and on the ground advice and to highlight and discourage bad practice.