Guest blog – A Pheasant Surprise? Possible Implications of In-Combination Effects on the Gamebird Shooting Industry by Richard Wilson

Richard Wilson is a professional ecologist with 20 years’ experience undertaking surveys for a range of clients, His specialist knowledge is in invertebrate and avian ecology, and his technical knowledge informs Environmental Impact Assessments, including when relevant, Appropriate Assessment.

His professional background has led to a keen interest in EU and UK law in the context of nature conservation. He is a full member of the Chartered Institute of Ecology and Environmental Management, a Chartered Environmentalist through the Society for the Environment and a Member of the Royal Entomological Society. He can be followed on Twitter (@ecology_digest).

He has written two previous Guest Blogs on Mark’s website: In Favour of the EU (in March 2015); and the Walshaw Moor blogs (1-68) (in May 2018). Both involved commentary on EU law in relation to nature conservation.

Mark’s two blogs of the 5th November 2020 (; and are of particular interest to me because I have had a long-standing interest in how nature conservation interacts with law and policy. Working within the planning sector, I, along with many other ecologists, engage with the Habitat Regulation Assessment process, which I will refer to hereon as as Appropriate Assessment.

A quick overview: An Appropriate Assessment is required when, “…a plan or project which are not directly connected with, or necessary for, the conservation management of a habitat site [European Protected Site], require consideration of whether the plan or project is likely to have significant effects on that site. (Article 6(3) of the Conservation of Natural Habitats and of Wild Fauna and FloraDirective 1992 (consolidated version: May 2013); ‘the Habitats Directive’.

Appropriate Assessments are therefore not new; having been a legal requirement for Member States since the mid-1990s and are currently transposed into domestic law by Regulation 63 of the Conservation of Habitats and Species Regulations 2017. The case-law and guidance has evolved substantially since then, there have been books written on it, and Courts have issued judgements such as ‘the Wealden Case’ (in 2017), which dealt with in-combination effects in relation to nitrogen emissions on the Ashdown Forest Special Protected Area (SPA). This Case, I believe, may have relevance to the current action by Wild Justice and are discussed further below.

Ecologists, including myself, who undertake such assessments on behalf of those who build houses, construct roads, erect powerstations or windfarms will be familiar with the approaches required to enable the competent authority to make lawful decisions.

So Wild Justice’s action over the release of gamebirds, and in particular pheasant and red-legged partridge is of professional interest, sufficient to warrant reaching the end of Mark’s second Blog of the 5th November (No. 16 in his series relating to gamebird releases). Mark quipped that if the reader got to end, they’d be interested (I am) and heroic (not so sure!).

My original intention was to add to the narrative on the 500 metre buffer with the additional point of in-combination effect(s) by way of a comment to Mark’s 16th post on this subject. However, the comment began to expand, and Mark has kindly agreed to let me submit a guest blog which is presented and offered as an additional voice and view of where the outcome of Defra’s gamebird review is currently at.

Mark’s various points are, in my opinion, broadly valid but whilst reading his last two blogs, it occurred to me that there was an additional consideration which has seemingly not been commented on elsewhere (or it has escaped my attention (at least)). This is, I think, an important point for Defra to consider if they intend to retain no more than a 500 m buffer and resolve, even in an interim manner, with a General Licence. This is a legal obligation and not one of policy or politics, and an obligation that has been in existence for many years: in-combination effects.

The requirement to consider in-combination effects is a consequence of the Conservation of Habitats and Species Regulations 2017:

63.—(1) A competent authority, before deciding to undertake, or give any consent, permission or other authorisation for, a plan or project which—

(a) is likely to have a significant effect on a European site or a European offshore marine site (either alone or in combination with other plans or projects), and

(b) is not directly connected with or necessary to the management of that site,

must make an appropriate assessment of the implications of the plan or project for that site in view of that site’s conservation objectives.

…and I think that considering in-combination effects is very relevant to the debate on gamebird releases. Why?

In the Wealden Case referred to above, the competent authority (Lewes District Council and the South Downs National Park Authority) was found to have not accurately assessed the predicted impacts of vehicle traffic emissions on the Ashdown Forest SPA as they only looked at their planning document; and not the neighbouring (Wealden District Council) planning document. Each document individually concluded that the emissions fell below the relevant threshold, whereas in-combination, they exceeded the threshold.

And whilst I understand there are nuances, such as at what point does the magnitude of a predicted impact become so tiny as to, even in-combination, negate the need to consider in-combination effects, the wider point that in-combination effects require consideration remains valid.

It is therefore not as straightforward as simply assessing the potential effects of an impact (or impacts) from a shoot in isolation of other shoots. Indeed, other projects/ plans, even if in terms of their operation, they are quite different to gamebird management require inclusion if the magnitude is sufficient to be measured and there is a realistic risk of significant adverse effect.

Thus, in the context of gamebird management, how could this play out?

As far as I understand, gamebirds defecate and in doing so, release nitrogen into the soil. In areas within 500 m, it is common ground that there are likely to be localised effects which may, or may not, be significant. Beyond 500 m, it is contended (by Defra and the shooting industry) that these effects are minimal and of no consequence; but this is disputed as conveyed by Mark in his 16th Blog. So, whilst it may be the case in a few, some, or more circumstances that effects don’t extend beyond 500 m, this isn’t a settled consensus. Hence, I suppose, why Natural England is going out to consultation.

But I would also argue that in the real world, land management (of whatever objective) tends not to operate in serene isolation. Down the road (in common parlance) or within the sphere of influence (in EIA parlance), it is not unreasonable to believe there could be a recently consented development which causes, for example, nitrogen emissions such as a new factory, processing plant or other infrastructure that emits airborne nitrogen. The development’s EIA has assessed that it emits 0.5 cubic units of nitrogen and the critical threshold for the nearby European Protected Site is 0.7 cubic units. These emissions will disperse downwind (mostly), and towards the sensitive habitats within the European Protected Site.

Mark used a heathland example (good choice!!) so I will unashamedly use this good choice (there are others) and give it the name Hypothetical Heathland Special Area of Conservation (SAC). The SAC’s sensitive habitats include an area of mire and bog with an important population of sundews and butterworts (which contribute to the designated feature), plus a vegetation community, that is highly sensitive to nitrogen inputs. 

Common butterwort (Pinguicula vulgaris): an example of a nitrogen-sensitive plant that grows in a nitrogen-sensitive habitat. Photo by Jörg Hempel, CC BY-SA 3.0 DE <>, via Wikimedia Commons

The new development is emitting nitrogen but the assessment, through modelling, concluded that the emissions (0.5 cubic units) falls below the recognised threshold of 0.7 cubic units because of dispersal.

In our scenario, there is a shoot located 500 m (nearest boundary, straight-line distance) from the SAC; and a second a few kilometres east of that one, and 600 m from the SAC. Each individual shoot adds 0.15 cubic units of nitrogen (so individually, well below the threshold of 0.7). But, the in-combination effects, with the consented development and each other result in total emissions of 0.8 cubic units of nitrogen, exceeding the threshold by around 12 %. It can be predicted with a high degree of certainty that the favourable conservation status of the SAC (its integrity) will be compromised (based on no mitigation).

Ah, I hear you cry, but both shoots are more than 500 m away from the SAC. Correct! And the pheasants themselves may mostly remain within 500 m (disputed!). But even so, and this may all be true (or mostly true, sufficient for the purpose of this illustrated example), this is not the end of the assessment.

The shoots are incontrovertibly at least 500 m away from the SAC, but that doesn’t mean the effects are constrained to within 500 m as Appropriate Assessment doesn’t just consider direct effects such as habitat loss directly caused by pheasants gobbling other vegetation, invertebrates or reptiles; but also the indirect effects. Indirect effects are secondary effects such as nitrogen emissions causing vegetation changes within the SAC; or may not be immediately obvious such as the inevitable pets arriving as a consequences of house building and thus, on sensitive adjacent habitats and ground nesting birds such as the Thames Basin Heath SPA.

So, to illustrate how, even if a shoot and most pheasant, remain within 500 m from a European Protected Site, let us return to the Hypothetical Heathland SAC.

There are two watercourses that feed the mire and bog and they flow from the shoots into it. The watercourses carry with it elevated levels of nitrates from the pheasants’ ablutions and enter the mire system. It is realistic to predict this could result in adverse effects on the SAC, by increasingly making it more difficult for those specialist plants that cannot tolerate nitrogen in the soil from surviving. Further, the increased nitrogen may allow other plants to arrive; e.g. grasses and taller herbaceous species which outcompete the more sensitive flora and gradually changes the habitat, affecting the fauna. The Hypothetical Heathland is also a SPA for its breeding nightjar population. The changes in habitat reduce the area suitable for breeding nightjar and so the SPA’s integrity is compromised too.

The integrity of the SAC and SPA is compromised, and it can be said that it is no longer in favourable conservation status. There is a legal obligation to maintain (or enhance) a European Protected Site’s favourable conservation status.

It can be demonstrated that even if gamebird management largely remains at a distance of 500 m (which may not be the case, but it is what Defra currently think is the worse case), this doesn’t equate to no significant effect.

Defra has also communicated that they intend to nullify the issue and meet its legal obligations by issuing an interim General Licence (GL) to accommodate all the necessary ramifications, subject to the results of a consultation. I have read this to mean a single over-arching, national (England) document covering all shoots, all in-combination effects arising from all plans and projects, everywhere, from Northumberland and Cumbria, south to Kent and Cornwall.

My immediate thinking is that the quickest way to achieve this would be to issue a GL that requires a substantially reduced number of gamebirds that are released below a threshold that is clearly going to shift the ‘emissions’ to a level that are tiny. But this number may be so small to accommodate all scenarios, that it becomes unworkable from the gamebird managers’ perspective. And if they are less cautious, will some protected sites remain vulnerable? In other words, what may be reasonable for a Yorkshire European Protected Site, may be wholly unreasonable for one in Northamptonshire, and in Hampshire but for entirely different reasons.

If this is the way Defra intend to deliver the GL, it will be very interesting to see how they derive the threshold; or if it is not, it will be equally interesting to see how they approach this conundrum.

And, as the example of a German woodshed described in Case-Study 2, and a larger project in Case-Study 3 (see here) attests to, it is also worth noting that Appropriate Assessment involve projects on entirely different scales and the consideration of a range of receptors. Thus, for a shoot with 10,000 to 20,000 birds, is the same approach applicable for 100,000 or 200,000 birds?

Thus, a catch-all approach may not be the sunny uplands that Defra aspires to; or the shooting industry wants. And this assumes that a singular threshold that is acceptable to the shooting industry can be achieved in a timeframe that enables the 2021 gamebird season to operate. Is it plausible that too high a threshold (regardless of buffer distance, and this has not been resolved yet either!) is reached, to the satisfaction of the shooting industry but which falls short of the legal threshold for at least one or a handful of protected sites?

In researching this blog, I happened across an example of a real-life application of the Appropriate Assessment and decision-making process on a not wholly dissimilar project. I think it is worth presenting it as a conversational point.

A proposed free-range poultry shed housing 16,000 birds in Shropshire, England was submitted for planning permission. This poultry shed is located approximately 700 m east of the nearest protected site, in this instance, the Midland Meres & Mosses Phase 2 *Ramsar Site in Staffordshire (see Figure 2).

Location of Midland Meres & Mosses Phase 2 Ramsar Site in relation to proposed (in 2017) poultry shed. OS Map & Ramsar Site polygon from; location of proposed shed from Shropshire Council Planning Portal: Reference: 17/01961/EIA

[*Astute readers will note that a Ramsar site is not a European Protected Site. However, for the purposes of Appropriate Assessment, Ramsar sites are included as part of Natural England’s legal requirement to secure compliance under Regulation 9 of the Conservation of Habitats and Species Regulations 2017]

As part of the planning application process, Natural England was consulted and responded stating that insufficient information had been submitted owing to a lack of assessment (i.e. an Appropriate Assessment) relating to the Ramsar site. The applicant undertook further baseline work, referencing Natural Resource Wales’ Guidance Note (GN 20): Assessing the impact of ammonia and nitrogen on designated sites from new and expanding intensive livestock units (which includes poultry). It also included modelling dispersal of ammonia (which contains nitrogen) and submitted this to inform the subsequent Appropriate Assessment. The Appropriate Assessment was completed, concluding that there WERE, in the absence of mitigation, likely significant effects on the Ramsar site’s integrity (Section 2.6 of the Appropriate Assessment, following their Table 2) as the ammonia deposition within the Ramsar site exceeded the threshold, albeit slightly (see Section 6 of the Ammonia deposition modelling report). With mitigation, it was considered possible to reduce the nitrogen emissions to below the threshold.

This real-world example illustrates the following points:

  • Land management involving lots of chickens can be more than 500 m from a European Protected Site and require (in the statutory authority’s opinion, to ensure legal compliance with Regulation 9) an Appropriate Assessment.
  • The exceedance of a threshold can be slight, and it remains the case that an Appropriate Assessment is necessary.
  • Published guidance, by a statutory authority, specifically related to free range poultry (how dissimilar are chickens to pheasant and red-legged partridge?) requires a mandatory detailed assessment if the land parcel is located within 250 m of a protected site; or if between 250 m and 5 km, potentially a detailed assessment if, in the instance of ammonia deposition, a threshold of 1 % is exceeded (based on an initial assessment). See Section 3 of the GN 20 Guidance document for details.

In my opinion, reliance on a GL and for it to be applicable solely within a buffer of 500 m could prove problematic when statutory guidance advises a requirement to screen sites within up to 5 km. Further, there is a wider debate on the regulation of agricultural ammonia emissions (see Anker et al., 2019), which I believe gamebird management may be included.

Writing this blog has been a useful reminder to me that Appropriate Assessment is not straightforward and requires considered thought and an eye for detail. I am not saying that releasing many thousands (or tens of thousands) of birds in a discrete location will always definitely have an adverse significant effect on all European Protected Sites. But equally, I don’t think it is reasonable to conclude that they always don’t, or that any effects are absolutely restricted to within a 500 m buffer. The Appropriate Assessment process is not an arcane piece of legislation; nor is it there to frustrate plans or projects, providing an obstacle course for practitioners to navigate for the sake of it. In my opinion, it is there to ensure that the detail is looked at, a closer scrutiny is undertaken when our most important greenspaces’ integrity are potentially threatened so as to ensure that when the competent authority grants permission for an activity, it does so with reasoned certainty and a high level of confidence.

Should society settle for less?


14 Replies to “Guest blog – A Pheasant Surprise? Possible Implications of In-Combination Effects on the Gamebird Shooting Industry by Richard Wilson”

  1. It seems clear that a fixed 500m threshold can’t possibly work. Releasing 30,000 birds 600m away from a vulnerable site is a greater concern than releasing 1,000 birds 400m away. There are so many variables, including number of birds, distance, sensitivity of the site, and landscape factors that influence the behaviour of released birds – where they move to after they are released.

    If 500m comes in as a threshold then I can see some large estates simply moving those release pens that fall within that distance and releasing higher numbers of birds beyond 500m to compensate. Those birds will then distribute themselves across the available habitat as previously. These things can only be assessed adequately (and so legally) on a case by case basis, not by inventing a hypothetical threshold and claiming that it will somehow magically work for every site and situation in the country.

    1. Ian,

      I wouldn’t say at this stage that a fixed 500 m buffer couldn’t possibly work; but it is a conundrum that Defra will have to answer satisfactorily and this may well prove to be extremely challenging. It might simply be easier to extend the buffer out.

      And your analogy of an estate moving their pens to a threshold beyond 500 m won’t necessarily solve the riddle. If the numbers of gamebirds released are large enough, even moving 1 km away may (I emphasise ‘may’) be insufficient if the magnitude of the impact is still likely to cause adverse effects. And of course, it might introduce another in-combination effect with another project that had been screened out previously.

      1. Hi Richard – Yes, that was my point really. Any fixed threshold will have workarounds that may still threaten protected sites and so result in legal challenge. The only way this can be done properly is to ensure that Schedule 9 applies to these birds wherever they are released. Then have a carefully worded GL that permits releases that are clearly non-problematic. Everything else will need to be assessed case by case. Anything else is just delaying the inevitable legal battle, though perhaps that is deliberate – just playing for time?

  2. Politicians like simple ‘solutions’. In a different context the mantra of building on brown-field land ignores the complication that often sites that are designated as brown-field are ecologically richer and more valuable than much green-field farmland. As you clearly outline, real life is often not amenable to such simplicity and in the case of land management, different projects can interact to produce combined effects that need to be assessed if we are to avoid unwittingly damaging precious habitats.

    The answer to your final question is a resounding no – we should not accept anything less than the authorities basing the authorisation of potentially harmful activities on adequate assessments of appropriate scope that enable them to reach their decision with reasoned certainty and a high level of confidence that the environment is protected.

  3. Richard – great blog! And it really got me thinking about how Appropriate Assessment applies to the South Pennines SAC which covers huge areas of Grouse Shooting Moor including Walshaw, where a designated feature is blanket bog. Over the years Natural England have issued management plans which in SSSI language authorise Operations Likely to Damage those protected sites. Burning blanket bog is an obvious one (but contentious), also with absolutely no conservation benefit rutting and compaction of peat from over use of vehicles, reinforcement of tracks with stone, bridge construction, construction of shooting butts using cut turfs, drainage channels and pipes around butts to prevent flooding. And no doubt a lot more. Given the arguments you lay out, how can any of this be legal?

  4. Of course in combination/ cumulative impact is not limited to like added to like. The impacts of additional nitrogen emmision adds to other background impacts. If you add nitrogen impacts to noise impacts and development impacts then you could easily cross the threshold where combined impact becomes significant.
    Much more challenging to assess but still required by law.

  5. “As far as I understand, gamebirds defecate (OK so far) and in doing so, release nitrogen into the soil” I think that should be “on to”. The fate of the nitrogen is moot, and dependent on many factors all of which are variable. For practical purposes the least variable is gravity.

    If we are to argue in the real world, it would be good to know what is hidden under the hood of the SCAIL software in the Finemere thing. In particular – does the it allocate deposition according to Met wind data; are there controls to remove the degree of spurious accuracy shown in the outputs. Because in the real world I doubt me that anyone, even in the digital age, can reduce fertiliser application by amounts required by the implied accuracy.

    The Anker paper I found very depressing – it shows how far down the rabbit hole it is possible to fall until an Alice v Major _ de Coverly shoot-out is required. When nitrogen deposition thresholds are calculated to the nearest 10g per hectare (ie one thousandth of a gram per square metre) from the assumed output of a standard bird with standard genetics fed on a standard diet and assuming that the deposition is from ammonia emission that magically travels west against a westerly prevailing wind to deposit itself uniformly over the area in question then there is something seriously wrong with the Reality.

    I can’t find a definition – anywhere – of a cubic unit of nitrogen. The nearest I can imagine is microgrammes of N per cubic metre.

    Another point – reactive nitrogen – and it must be reactive-N we are discussing as (di)nitrogen is irrelevant – is a very slippery customer. Blink and it’s gone somewhere – probably combined with some carbon as organic matter as you can’t have the latter without it – or leached into drainage. Whereas the phosphorus in poop will be a very long term legacy wherever it is dumped & I suspect will cause the most lasting real-world impact from high concentrations of livestock

    1. Hi Filbert, and thanks for your comment

      I take your point about ‘on to’ versus ‘into’ regarding faeces and soil and not a point I was anticipating getting pulled up on! May be I slipped in to common parlance?

      I am not the person to ask what is under the hood of SCAIL so am afraid, I cannot respond to this element of your comment.

      I used cubic units merely for ease of reading and to numerically illustrate my point. I thought that by using ‘cubic units’ at least provides the more informed reader the ability to insert the appropriate one, but still get the substantive point across.

      I am aware that P has a longer lasting legacy than N in soils but I cannot comment in more detail; other than to say that I recognise that N (in some form, eg as ammonia) would appear to me (and Shropshire Council at least: – to be a consideration. Perhaps it would have been more accurate for me to have used ‘ammonia’ as opposed to ‘nitrogen’?

      Best wishes


      1. Into / on to: it’s a small point but relevant – key measure to reduce ammonia emissions from manure spreading on bare land. Spreading eg FYM on grass stubble after silage cuts guarantees most of the crop-available N will be lost as ammonia.

        The SCAIL software may be useful as the needs of the farming elements of the Clean Air Strategy emerge – but it needs to be based on realistic scenarios of field situations / operations otherwise it’s GIGO

        N in all reactive forms is up for consideration but what I am puzzled by is the apparent disinterest in P or its possible absence from EI regs – when as the 2nd limiting element it determines the environmental impact of elevated N.

        Fenemere / Finemere: it’s a small typo but relevant – one is in Shropshire and my version is in Buckinghamshire. Duh!

  6. I understand why DEFRA would want to streamline the Likely Significant Effect (LSE) and Appropriate Assessment (AA) process. I don’t quite understand why the taxpayer is stumping up for the staff time and the proposed research to inform the process

    My understanding is that it is the ‘Proposer’ who is (at their own expense) required to demonstrate to the Competent Authority beyond reasonable scientific advice that there will be no LSE. If there is LSE then again the evidence should be gathered and presented by the proposer (at their own expense) to inform the AA carried out by the Competent Authority.

    Now I know these principles have been stretched at times for example guidance and research provided on landscape assessment or peat management for say windfarm businesses, but I can at least see some Public Interest that might go some way to justify that spend.

    I struggle to see much public interest in facilitating the attempted shooting of 60 million pheasants and partridges.

      1. Who is ‘some’ and what is there evidence for those figures? The figure of 57 million comes from the GWCT and given the voluntary nature of the bag census, is likely to be a considerable underestimate. I’d suggest it’s well over 60 million and the rest.

  7. Brilliant! . . . Well! after reading this i will never look at a pheasant shit the same again! . . So much toxic potential.
    Maybe we should cut down any trees within 500m of protected sites to then? Preventing birds from roosting in them. Have you ever walked through a roost wood after pigeons have been eating rape in winter? Stood under a starling roost or rookery? It’s bad enough if you park your car under a tree for one night this time of year. Especially if birds been on the berries. How toxic? We could shoot all/more pigeons to help you out. As Paul reckoned we need to kill 80% a year to have any effect on numbers anyway. And don’t get me started on the 1000’s of geese that many turn up anywhere every winter. I think the poor old snake goggling pheasant is getting a bum deal. Folk always trying to drop him in the shit! .

    Are you and others really serious about killing pheasants and partridges in gardens under GL’s Mark? Would that mean year round? If so, it’s not the killing you have a problem with then? It’s us “toffs” shooters! As we have known all along. What would be your method of killing in the confines of a garden with your aversion to lead shot? How would you dispose of them? Would you eat them or put them in the food chain. Maybe Tim (who shared his wisdom on another pheasant topic) who only has time to “dispatch” 200 hundred pheasants a year in his garden. (a thousand if he had time) could help with advice. Would you also suggest a XL bird table like he had and feed them to kites and a visiting eagle as he said he did? . . . Fantastic!

Comments are closed.