Guest Blog – Adders and Buzzards by Nicholas Milton



Nicholas MiltonNicholas Milton has worked for the BBC Natural History Unit, the RSPB, the Wildlife Trusts, Greenpeace and the Ramblers. He is a freelance journalist and writes about the environment, politics and the Second World War. He is also a marketing and communications consultant and is currently working with the international development charity Practical Action.

Nicholas Milton website.







Last month I wrote a comment piece for the Guardian on whether we can save the adder from extinction in middle England.  My argument was that the decline of the adder was due to many reasons including habitat destruction, persecution, inbreeding and the killing of young adders by pheasants but what was pushing the species over the edge was the spread of the buzzard. The article caused quite a storm.

It was not an easy article to write as I am a big fan of both species. My first job in conservation was working with Mark in the RSPB research department back in the early 1990s. Back then the buzzard was quite rare in middle England and its spread after decades of persecution is a great conservation success story. I still get a kick from seeing a buzzard while driving along in my home county of Warwickshire and my wife is forever telling me off for craning my neck to see one when I should be concentrating on the road.

Ironically it was also at the RSPB research department that I learnt about adders. As a young researcher working on the decline of farmland birds I had pinned up an adder skin above my desk. One day out of the blue I was asked to report to the RSPBs Director General, Ian Prestt. Not as bright as Mark and without a published paper to my name I was convinced I was going to be sacked. Instead to my surprise Ian asked me where I had got the adder skin. It turned out that Ian’s PhD had been on the adder and he asked if I would like to go and see a colony with him. Over the next year we went to see adders on many occasions, including memorably with the late Derek Ratcliffe.

Ian’s boundless enthusiasm and knowledge triggered in me the start of a lifelong love affair with Britain’s only poisonous snake. Since then I have continued to monitor adders at two colonies, one in Greater London where I used to live and one at a nature reserve in Oxfordshire (sadly one of the nearest sites to my home in Warwickshire where they went extinct many years ago). Both have always supported small populations of no more than 10-20 snakes. However, this year there has been a catastrophic decline and there are now no more than 3-4 snakes present at each.

adderIn the case of the Greater London site I put the decline down to the very wet winter and disturbance, it being a small water meadow near a public path. However, in the case of the reserve in Oxfordshire the decline is harder to explain as the site was unaffected by the floods and the warden has gone to great effort to create the right habitat for the species.

One evening after a visit when I had failed to find any snakes, I got into a long conversation with him about why the adder had disappeared from the reserve over the last few years. The site is located in the centre of red kite country in the Cotswolds and is patrolled almost constantly by both kites and buzzards. On a previous visit I had seen a buzzard with a snake in its claws and although I couldn’t tell the species, I strongly suspected it was an adder.

The warden told me that despite the presence of the kites, he also thought that it was the buzzard that had killed most of the adders. Apparently although mainly a scavenger, the buzzard is an intelligent bird and if it finds a snake will go back time and again looking for more. Given how vulnerable adders are when first emerging from hibernation and how common the buzzard has now become, we both concluded that it was the most likely cause for the disappearance of the adder from the reserve.

Of course implicating the buzzard in the decline of a species like the adder is manna from heaven for those gamekeepers and landowners would like to see buzzards taken off the protected list and culled. In the past few years under this government the buzzard has become the cause celebre when it comes to trying to reintroduce the control of birds of prey. That was why I was very careful in the article to state that for high profile shooting journalists like Patrick Laurie they have become a convenient excuse rather than a conservation cause. I also stated that as well as the buzzard we urgently needed research into the impact of pheasants killing young adders.
When I published the article I predictably got roundly attacked by conservationists but less predictably found myself in the deeply uncomfortable position of being supported by the shooting lobby. Many of the most vitriolic comments posted on the Guardian and sent to me via Twitter were understandably from people who wanted to protect the buzzard. In contrast Lucy King, the news editor of Shooting Times, stated on Twitter “such a pleasure to read such a calm and reasonably put piece” (although I’m still not sure if she was being sarcastic) while Patrick Laurie penned a memorable blog about me entitled The Evil Gamekeeper. In this he railed against the fact I had described him as a gamekeeper, not a journalist but somewhat gave the game away when he stated “my response to seeing adders killed by buzzards… to ask if the life of every single buzzard in Britain is individually more important than the survival of an entire species”.

Given the extent to which we have destroyed the natural world, perhaps we should not be surprised that these conservation conflicts are likely to be used politically by those with a different agenda. I often think what the late Ian Prestt would have made of the controversy. Sadly what I didn’t know at the time of our visits was that he was dying and he passed away not long after I left the RSPB (I attended his memorial service at St Pauls Cathedral and took along an adder skin as a mark of respect). I strongly believe that despite his deep love of birds and his position as the Director General of the RSPB he would have supported a rationale debate about the role of buzzards in the decline of adder.


22 Replies to “Guest Blog – Adders and Buzzards by Nicholas Milton”

  1. I think like most people with an interest in conservation, I would agree that we need to do real research into the effects of many things (including releasing millions of Pheasant), we can’t now expect nature to balance itself since we removed many of the larger predators.
    But my issue with what you have written is that there is so much supposition going on.
    There are many questions to be answered before we can begin to pin any decline on a single species.
    It is simply not enough that you see the rise of one species and the fall of another and presume that they are linked, it is hardly surprising that you saw support from the shooting elements, they justify the illegal persecution in many upland areas with the same kind of logic.
    Adders were long gone from this area, long before Buzzards returned, in fact using the same logic I think that either the increase in cars caused it or else the grouse must have eaten them all.
    The last thing any protected species needs, particularly one that is being persecuted heavily already, is for people to pour fuel on the fire, it’s akin to blaming the song bird declines on the Sparrowhawk.

    Species that co-existed in the past are suddenly unable to do so?
    How come there are large areas where Common Buzzard have failed to recolonise and these same areas have also seen declines or even localised extinctions of the Adder?
    The only place I have seen Adder is in Wales, which appears to be an Adder bite hotspot, where surprisingly Common Buzzard have done extremely well and for much longer than many other areas.

    1. I completely agree. So much correlation, so little causation.

      A but like the latest bit of research coming out of Langholm – buzzards are up, grouse are down. But when it’s looked at properly and systematically, it shows that buzzards aren’t after the grouse in any serious way at all. Supposition without proper evidence is a dangerous thing.

  2. Nicholas (and Mark et al.)
    I missed your original article, but I’m not surprised to read it now and your post here. My students have been carrying out research on adders in north Yorkshire for the past five years, including on predation. The main substance of the work isn’t yet published but it’s clear that avian predation is a significant threat to individual adders, though the population-level impacts of this we can’t really estimate. My feeling, supported by some evidence, but not definitively, is that predation risk and the impact of predation are habitat mediated. So I can see how the (re)colonisation of a predator into a much modified landscape might drive regional extinction. In upland sites, habitat simplification/modification through sheep grazing may well have exposed adders to high predation (from corvids as well as raptors) and my hunch is that that would explain things like the near extinction of adders in the peak district. Fortunately the north York moors has some outstanding sites for snakes, and a few buzzards too!

  3. I have to disagree. Twenty and thirty years ago when I lived in the lake district it was the only place I knew where I could see both adders and buzzards. I would suggest that adders are right on the edge of where they can survive here in the UK and that loss of habitat, human disturbance, moorland management, isolation of small populations and the recent(not the last) very long cold winters here in the midlands have pushed them to the edge.

  4. Very interesting. We have a wonderful area with Adders and Buzzards. I think there are a few things that the public should be told. Adders have been generally killed by keepers in their areas due to them thinking they are like Carrion Crows and could threaten their dogs working the moor! The burning of heather is at the same time of the Adder coming out to bask. Bracken is the saving grace for Adders but with 70% removal of Bracken at places like Langholm in upland areas and paid for by you under High level Stewardship the Adders are under greater threat in upland areas and especially on Red Grouse moors. All Adder sites here are away from heather and in Bracken. Last year an Adder was watched eating a Red Grouse chick by a keeper in Scotland!!
    The Buzzard have increased but if you start killing them you are just creating a void for other Buzzards to move into. This means it is impossible to save your southern Adder population unless habitat management can be carried out and it looks like you have acted too late!

  5. We do tend to get very divided when subjects crop up like this and it is about time that we were able to sit down and discuss these issues. Although I suspect there is more of that going on than we realise , we just need it to be open.

    Nicholas, I did lose a pub quiz once when doing exactly the same as you I put the adder down as the only poisonous snake in Britain. The correct answer was there is no poisonous snake in Britain as the adder is a venomous snake. Although if you get bitten I suspect it doesn’t matter much.

  6. I think you’ve both hit on precisely the issue, the problem is likely to be multifaceted, with things such as predation in various forms having some varying effect dependent on where the population is.
    There is a danger that if you can get hung up on one issue and misdirect your conservation efforts, for example we could probably prove that Adder populations recover to an extent when you remove certain pressures, what you haven’t got though is a) an answer to what is the main driving factor of the declines and b) a workable long term solution.
    Another question that spring to mind is what effect have the recent return of some very cold winters had on populations and their prey? Certainly we have seen a number of bad breeding years in this area for small mammal eating raptors.

    Not to mention the effects of chemicals such as brominated flame retardants (BFRs) to name but one.

    I just don’t support the way that Buzzard are continually targeted as a scapegoat due to their highly visible presence, with what appears to be little or no research to either prove the effect they may or may not be having or to even prove if they are a major factor in cause of the declines.

  7. It is clearly possible that predation could lead to local extinction of isolated colonies, as could a variety of factors or events including poor weather, inbreeding, fire etc etc. The crucial phrase in Nicholas’ piece is perhaps ‘pushing the species over the edge’ but the more important question is what brought it to the edge in the first place.

    To implicate buzzards as the key factor in the decline of adders seems to be based on circumstantial evidence at best and whilst it may be a reasonable question to investigate further it was perhaps inevitable that airing it in the national press would be seized upon by those who are keen to see buzzards culled for other reasons.

  8. And herein lies questions that we might not like to answer, do you allow a species to attempt to evolve (or re-accustom itself to certain predators and influences) and risk it not being able to and if not how else do you combat the problem habitat improvement seems like the most likely answer.

    I am unsure that there is a viable control method for avian predators, uninhabited suitable habitat will always be a draw to birds looking to breed, and to non breeding birds and I don’t think we can afford any more ‘black hole’ areas for predatory species, perhaps we need to look further afield to places where snake populations and predators manage to coexist and the influence of man is less intensive.

  9. Personally I think the issue is quite obvious.

    Adders are now forced into pockets in the UK, sanctuaries that they can survive in but like islands in amongst the towns, cities, farms etc where they can’t and don’t want to move through.

    Over time these Adder islands are going to deteriorate in terms of the quality of habitat (unless very well managed), they are also going to be the focus of disturbance from reptile enthusiasts, photographers etc and are often places where people go anywhere for dog walking etc. The gene pool in these islands is going to be poor as there are no new adders entering and predation from a number of species whether that be fox, buzzard, pheasant is going to occur – if you add up all of these factors then it is no wonder that this species is suffering.

    For me I see absolutely no point in targeting the predators, in the short term it may just about save the remaining Adders in each island but in the long term that does not solve the problem.

    What we need to focus on is joining up Adder habitats, giving Adders more space, a better chance of improving the gene pool and with more adder sites the pressure on them from predators and people may ease.

  10. Thank you to Mark for posting my blog and for all those people who have commented. I thought some very good points were made. What I was trying to do was start a debate. Thanks to all of you I’ve succeeded in that at least! The key phrase in my piece as Jonathan Wallace picked up is whether or not the buzzard is pushing adders ‘over the edge’. Buzzards are clearly not responsible for the decline of the adder in middle England. And of course as a priority we must address all the other factors I listed, particularly habitat destruction and the effect of pheasants. However, in my opinion that should include a rationale debate about the role of the buzzard in those counties where the species is on the edge of extinction. The reason I highlighted middle England is because here most adder colonies are very small (20 snakes or less) and they are under the most pressure from habitat destruction, urbanisation, isolation, disturbance etc. Colonies elsewhere will be different and Im sure they can co-exist. Gordon/Mike I agree there isnt the evidence. Thats why we need the research (by the way that phrase would have been music to Marks ears when he was head of research at the RSPB!). Bob yes youre absolutely right and I stand corrected. Sorry you lost a pub quiz over it. Ben I thought you summed up the issues very well. Habitat will always be key. However, sadly the populations in the Midlands are now so small and isolated that joining up habitat is unlikely to work or be feasible. Bringing in adders from elsewhere will help as long as they are then given a chance. After all that’s what we did with Red Kites. Does that therefore mean we should cull buzzards in the vicinity of a county’s last adder colony? No. And we should be rightly very dismissive of any gamekeepers who suggest this. Does that mean we should consider non lethal methods of predator control? Possibly. Its a real dilemma but one as conservationists who are meant to be standing up for all of nature we cant ignore.

  11. Purely in terms of the argument, it seems to me to be like us going down to Wolves on Saturday week needing to win to stay up, then blaming Wolves for sending us down if we lose.

  12. Thank you for the interesting article, research is indeed the key and is something that interests me greatly, I just want to add that it would all be for nothing if the root cause were not identified and resolved, you can perhaps mask the problems short term with predator control and I do believe it has a role to play, but without tackling the cause it is just delaying the inevitable.

  13. A small additional thought to throw into the more general predator/prey debate that seems to be playing out more widely on this blog:
    (White, T.C.R. 2013. Experimental and observational evidence reveals that predators in natural environments do not regulate their prey: They are passengers, not drivers. Acta Oecologica 53: 73-87).

    A caveat: I’ve only skimmed this for the time being, but it has some very interesting comments on human attitudes to predators as well as a lot of persuasive evidence about predator-prey relationships. If you take it at face value, perhaps the focus above ought then to be: what’s happening to the adders’ favoured food supply?

  14. A well put together article and the following comments are equally revealing and relevant. I think Ben summed it up perfectly in his comment, Adders are under so much pressure, trying to exist in small fragmented populations in sub-par habitat (both in terms of quality and size) that even the slightest disturbances (one of which could be predation incidents) will tip them over the edge.

    It is an age old question for the conservation sector, that seems to be becoming more and more relevant as environmental destruction, habitat loss and species populations declines marches on. That is: how do we most effectively use our seemingly dwindling resources to manage tiny populations of species? Do we spend lots of money and time trying to keep going a small population of Adders, potentially doomed to fail in the long run?

    It is such a hard choice to make, we feel we must do something, we cannot just let these species die out. Yet when resources are tight and time is precious can we? It is sustainable to keep them going?

    I think habitat is the key, but what about in the short term? Do we let them go extinct and re-introduce in the future when we have better, and crucially more, habitat. I think habitat management for Adders would essentially be creating more predator refuge areas anyway, thus using non-lethal measures to combat Buzzard predation. It is something for those that are responsible for the habitat management of Adder sites to be aware of: are there enough areas for them to hide from predators? As Buzzards are generalists and doing well, and seemingly abundant, could some of our Adder sites be more targeted in their management for Adders and try to somehow exclude Buzzards from them? Of course though, this all assumes that Buzzards are a main driver and a big problem, something I think we do not know and desperately need research into.

    We know why Adders have decline. We know the main reason, it is the main reason for so many of our declining species: habitat loss. Until we can win the battle against this and start large scale landscape restoration projects and making bigger better areas of habitat then I think possibly Adders may indeed continue to decline. But we must not give up, and I don’t think we will, as there are so many hugely passionate and committed conservationists out there doing great work, who will not stop.

  15. Thanks Nicholas for acknowledging my points and I too acknowledge what you are saying.

    I currently follow 2 Adder populations in Bedfordshire, I am not personally aware of any other populations in the county but would love to be proved wrong and shown another! Both populations comprise of less than 10 snakes in each, one of them I am sure now only contains 4 individuals.

    The populations are 12 miles apart and there is no possible way that they could reach each other as there are fields, cars, buzzards, roads, pheasants, houses, cats, kids, rivers etc in the way….I doubt any Adder would want to tackle all of that!

    So what is the solution? I would love to know it! The way I see it it can only be one of these choices:

    1. Join up the two sites using a massive wildlife corridor – Is this really an option?!

    2. Add more Adders to both populations increasing the gene pool – Is this a stop gap and will the populations dwindle again?!

    3. Let both populations die out and lose the Adder in Bedfordshire

    4. Remove all Adders from the sites and donate them to other populations that may need them and are doing ok, we lose our Bedfordshire Adders but at least the individuals Adders survive elsewhere and help out another population

    5. Designate 5-10 new Adder sites in the county that can go some way to joining up these 2 sites and give the Bedfordshire Adder a fighting chance! – If this is recreated across every county where they are struggling will the population be better off in the long term or is this just another short term fix?!

    6. Control every single cat, buzzard, pheasant and fox at the 2 sites and don’t let any dog walkers or “normal” human beings enter the sites to protect what is left only for them to naturally die out anyway – NO WAY!

    7. Work on improving both sites whilst also introducing some new blood to both, if the sites are better improved and there are a few new Adders added to the gene pool then both populations may survive, they may grow in number – with improved habitat and less disturbance young Adders have placed to seek refuge giving them a good chance to grow and the population to increase. New blood may have to be regularly added. Some predator control may help and may be required until the population is on its feet but in my eyes I would not like to see this especially as there isn’t much research into how much predation affects a population.

    This is Bedfordshire’s Adder predicament, if I have missed off a alternative strategy I would like to hear it…..maybe its just a combination of all of them and the last question is…..who does all this!?

    Amphibian and Reptile Conservation? RSPB? Natural England? Bob and Sue who are retired and love Adders and run a volunteer Reptile Group? All of us?

  16. I sadly feel the biggest impact on adders is human rather then avian. You seem to have left the kestrel as a cause to decline and concentrated on kites and buzzards, I’ve photographed the following species predating both adders and grass snakes Kestrel,Buzzard,Red Kite,Little Owl (which was a surprise),Fox and humans, after all think of this, before we started killing our birds of prey and persecuting them in great numbers and bird of prey numbers were at a healthy level was the adder still around? I think it was…..

  17. I am very interested by this blog. I have been monitoring one of the two Bedfordshire populations referred to by Ben, I suspect he is referring to the non-introduced population near to Leighton Buzzard – first, the good news, in the nearly twenty years I have been photographing and watching them having ‘rediscovered’ them in 1996, the population has been stable with only minor fluctuations yearly – currently, I estimate the population as a healthy thirty or forty individuals, not ten! I discover new adult Adders each year suggesting that there are more snakes in out-of-the-way areas down here. Three years ago, I had the best year ever with fifteen females seen and five males. The other location is a reintroduction site and I have no first-hand knowledge of this one, I’m afraid. Last year, the very hot late summer meant I saw absolutely no snakes at all between late August and March this year, despite intensive searches. I liaised with other watchers around the country who reported similar issues – today, I have just run a Reptiles Workshop with Helen Muir-Howie, the Bucks county recorder and we found a new female, probably between five and seven years old – brilliant news!! I have noticed over the past ten years that sightings drop off to sometimes nil between late April and mid-July. My ‘theory’ is that the increase in breeding Kite and Buzzard here means that they are feeding young at this time and the Adders simply don’t show themselves in the open to bask – it seems to fit and I’ve seen Buzzard nab Aesculapian Snakes in France so why not Adders here? We have also seen Raven over the area regularly so I think Nicholas’ theory is sound, I don’t see his comments suggesting we should ‘control’ raptors, he is presenting a theory and it matches what my observations have suggested for some years so perhaps it is worth noting. But it IS DEFINITELY the pressure on habitat which is the principle cause for concern in the UK, the site Ben and I know is the only natural Adder colony in some two-thousand square miles of arable, road and pasture desert – wow, that’s some desert, isn’t it but it is true, the maths fit!! But, critically, a population of only ten Adders would not survive long without fresh blood and as there is no way for fresh blood to come into this small, isolated but still thriving colony and I am seeing new adult snakes each year as well as the regulars, then there is hope for the future in my opinion!! Oh, and I am gutted that I didn’t publish my theory years ago – I’d be dead famous by now and lunching with Royalty – or even Nicholas, no doubt!!

  18. I have no doubt that Buzzards can have a major impact on Adders, I have witnessed Buzzards taking Adders in the New Forest many times, and once they find a basking area they will repeatedly visit and often hunt from a static position (e.g. overlooking trees). Saying this Buzzards are a natural part of our fauna, so losses must be accepted, and I doubt very much that Buzzards could be solely responsible for demise of any but the smallest populations. The problem arises in the New Forest where management such as heather burning and bracken harvesting opens up the ground on hibernation/breeding/basking sites, thereby making adders much more vulnerable to predation. The problem is the human species, as usual, rather than the Buzzard. We have little in the way of Pheasants except on the Forest margins, so that impact can not be relevant in all cases, in fact, the best site I monitor has plenty of Buzzards and Pheasants, but the habitat is such that their impact is limited. In other news the return of Goshawks to the New Forest has really dented the numbers of Grey Squirrels, though they take Hawfinches, Lesser-spotted Woodpeckers and such like too!

    1. Richard – welcome and thank you for your comment. It’s so long since this post appeared that few will see your comment – but I enjoyed reading it.

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