Nigel Hand, a professional herpetologist, has been at the forefront of UK reptile and adder conservation and research for over twenty years, developing a methodology of external radio transmitter attachment to track this relatively small snake. His monitoring reptiles and radio tracking adders has provided valuable insights into their secret habits and the issues they face in the 21st century.
Growing up in Stourbridge, in the heart of the West Midlands, adders were scarce in the industrial landscape, but grass snakes and smooth newts were always plentiful along the banks of the canal or the cut as locally known. In my Wollaston Secondary School I was fascinated to come across two freshly sloughed male adders in the woodland edge above the school playground, which rather shows how undisturbed and wild the edges of my school grounds were in the 1970s. I even dragged my teacher and class mates out to see them. More recently I checked out this area and although the woodland is still there the understory is well worn with paths, little undergrowth and could not be called wild – the adders are probably long gone.
Herefordshire has been my home for the last 30 years living a much more rural life and both my work and my passion is adder conservation. I want to see the adder thrive on the quieter hillsides and commons where it has lived for centuries. A shy and beautiful creature, living in the most undisturbed habitat, and Britain’s only venomous snake making support for it occasionally problematic, I fear I’m fighting a losing battle as their numbers continue to dwindle and their habitat issues become greater. One of these impacts is the cultivation and shooting of large numbers of the non-native ring neck pheasants on herptile species.
Many shooting estates have raised pheasants for over a hundred years and adders have been persecuted for longer still. An extract, from one of the earliest books on the adder, referenced gamekeepers killing adders on a Herefordshire hillside at the end of the 19th century, illustrating the extent of time these birds have been released into the countryside and the levels of prejudice and unwarranted fear.
‘The game keepers kill a considerable number of adders every spring (the woods on both Garway Hill and the Graig are heavily preserved with pheasants), but apart from that the adder population is very secure in the Monnow Valley’
Extract from the book ‘The Life History of British Serpents and their local Distribution in the British Isles’ by Gerald R. Leighton 1901 (Chapter 14 the Ophidia (Snakes) in the Monnow Valley page 203.)
Thankfully the adder is now protected by the Countryside and Wildlife Act 1981 schedule 9 from intentional persecution and injury but unfortunately not protected from steady decline and Leighton’s comment that ‘the adder population is very secure in the Monnow Valley’ is not the case any more.
A single shooting estate, near one of my long term SSSI monitored adder sites, releases 60,000 birds annually, along with many smaller local shooting syndicates also putting out birds, resulting in unnaturally high number of pheasants foraging across sensitive habitats.
The annual release of approximately 38 million (likely an underestimate) industry reared non-native pheasants is believed to be worth £350 million to the UK economy alone (Slade 2005; Aldous and Alexander 2008; DEFRA 2008).
The Game & Wildlife Conservation Trust (GWCT) recommends release densities not to exceed 1000 pheasants per hectare; however this is not enforced and is sometimes greatly exceeded with up to 5000 pheasants per hectare of release pen recorded’ (Sage, Ludolf and Robertson 2005).
‘The Midlands is a region of particular concern as the adder is in greater decline here than elsewhere and, to a lesser extent, slow-worm population declines are also evident. Many of the populations reported on were relatively small. A third of adder and almost a quarter of slow-worm populations were reported to consist of fewer than 10 adults.’
(English Nature Research report no 546 Baker et al 2004), (Gardner et al, Make the Adder Count population trends 2019)
Across Herefordshire and the vast majority of lowland Britain adders have become restricted and localised. They are now considered extinct in Nottinghamshire, Oxfordshire, Warwickshire and Hertfordshire. Many populations exist on islands of habitat, surrounded by intensive agriculture, urbanisation and busy roads preventing mixing of populations and making them extremely vulnerable to catastrophic events, but also suffering a slow decline in genetic variability.
In Herefordshire, Worcestershire and Gloucestershire the species exists in low numbers at a handful of sites. There is current work looking into the feasibility of reintroducing adders back to former habitats but if issues such as predation cannot be addressed this is going to be a wasted opportunity.
This ‘islanding’ of adders can also be due to non focused management, excessive site grazing and the removal of scrub and mature heath, which provides security, thermal gradients and linkage corridors for wider dispersal. Mature commercial conifer, with its lack of understory, open glades and ground cover has extremely limited value to adders and other reptiles. Adders prefer track and ride edges, favouring open fringe areas with nearby taller, structural habitat which they can retreat into on disturbance.
Adder sites have ‘hotspots’, usually hibernacula or thermoregulation areas, in early spring there may be a concentration of newly emergent snakes in these foci areas. This reliability and faithfulness to an area is particularly seen in female adders who may move only a few metres between the same bramble or gorse blocks over the course of a year. Adders favour gorse (Ulex sps), bramble (Rubus fruticosus), rough grassland, bracken (Pteridium aquilinum) and mixtures of these habitats and preferring sandy, acidic well drained soils rather than wet clays..
It is argued that managing woodland rides for gamebirds will result in favourable habitat management for a range of species, including reptiles, but if thousands of birds are annually released on or near vulnerable reptile populations this will not be beneficial.
Between 2008 and 2010 adders were monitored (Hand 2008-2010 report to Forestry Commission unpublished ). One of the best reptile areas was in a young private larch and conifer plantation and had a peak count (over a single day) of 52 adders. This was an exceptional site for the West Midlands with grass snake, viviparous lizard and slow-worm numbers also high.
After 2010 the woodland began to shade out and the landowner placed pheasant feed hoppers along remaining ride edges. As a consequence of both shading impacts and grain feeders attracting and holding pheasants the reptile sightings plummeted, so much so that only 4 adders were recorded in the 2019 survey year (S.Sheldon et al 1990-2019). It must be pointed out that the landowner did remove the feed hoppers when asked and attempted to cut back some of the larch and conifer, but so far it has not been enough and there has been no noticeable recovery to the originally high numbers here.
Surveying on the Warburg Nature Reserve SSSI adder site in Oxfordshire in 2011, to assess the feasibility of restoring and improving habitat for reptiles revealed that only one large female adder remained. No other adders were ever detected and the species is now considered locally extinct on this site. Warburg borders a shooting estate and although the actual demise of adders on this site cannot conclusively be put down to the impacts of a long term pheasant shoot, it is highly likely this does play a part. Any plans to return lost reptile species must consider the proximity of shoots that operate nearby with1000s of annual bird releases.
The decline and loss of a native species and even the complete loss of the Oxfordshire adder should carry a greater conservation importance. Adders can be long lived. Females only breed every two to four years and on average give birth 1.3 times per lifetime. The short reproductive life is a consequence not only of mortality directly related to the reproductive activities, but also of mortality associated with recovering from the weakened post-parturient body condition during the long intervals (1–2 years) between reproductive bouts. (Bauwens et al 2019)
Pheasants impact reptiles in a number of ways. Pheasants’ natural foraging behaviour has been seen to unsettle basking adders. I witnessed an adult male adder noticeably agitated by the close presence of pheasants, exhibiting deep rapid breathing and hissing behaviour. This was on bracken and grassland hillside during long term monitoring of a small and vulnerable population of 13 photo identified snakes. Pheasants, like many birds, are attracted to the reptile’s wriggling, sinuous movement and attack either as a predatory or as an inquisitive response. Snakes may even be perceived as a threat to broods by hen birds.
A recent article in the Scottish Courier newspaper (2017) showed this exact behaviour, although the paper described it a little differently “Remarkable moment Scots gamebird fought off venomous snake!”. The native adder is in reality attempting to flee from the predatory game bird. Video link
Reptiles are ectotherms meaning they must bask in the sun to warm their bodies for activity. The presence of game birds will reduce the length of time reptiles spend openly basking and vulnerable to disturbance and attack. This in turn could lead to health complications, reduced vigour and impacts to breeding with possible low recruitment into populations.
There are photos of pheasants eating wild reptiles, a juvenile grass snake was photographed being predated by a hen pheasant and the birds have also been recorded taking small rodents such as voles and mice and also invertebrates; all prey items of UK herptiles species. Many may believe that as the adder is venomous it can therefore defend itself, but this does not appear to dissuade these large birds who will attack and easily immobilise a full grown adder and seem able to avoid a venomous bite.
I have witnessed an attack on a 40 cm female adder by an adult cock pheasant on the Malvern Hills. The adder was left with serious damage to both eyes and head from its beak (see above) probably leading to a lingering death or predation. The question is how often is this happening across UK reptile sites. The pheasant was unlikely to eat such a large snake but the attack still immobilised and damaged the animal beyond recovery. My identification photos show adders and grass snakes with body and head scars, blinding, and also slow-worm and viviparous lizards with regenerating tails and scarring. This will not be solely down to pheasants but due to the sheer numbers of annual releases they are a serious concern.
Research into the impacts of pheasants on reptiles is difficult to assess because of the secretive nature of reptiles and typically low site carrying capacities. Recent DNA analysis of pheasant faecal samples failed to identify reptile DNA, even when DOR dead reptiles have been fed to captive birds on a research project. A pheasants diet in the wild is known to include reptiles, invertebrates, small mammals and amphibians. When feeding young captive pheasant poults reptile casualties, including roadkills, of grass snake (Natrix helvetica) and slow-worm (Anguis fragilis) (Westbury et al., University of Worcester, unpublished data) it was noted that the birds readily consumed the these and appeared to recognise it as a valued prey source. Group feeding behaviours changed with birds becoming competitive and attempting to chase those with the reptile morsel.
Each July and August pheasants are released from their pens and disperse away from the shooting fields and woods, often taking up residence on important wildlife areas even SSSI NNR. There are even pheasants being released on a few NNR and SSSI sites! The timing of pheasant releases coincides with the birth of native reptile species and on my study sites where the pheasants gather after release on the warmer south facing slopes no viviparous lizards or neonate adders are seen.
Pheasants appear to inhabit the same favoured ecotones or micro climates that reptiles occupy, south facing glades amongst early successional vegetation such as bracken, gorse and wooded fringe. Evidence of pheasant occupation on reptile sites is seen in dust baths, piles of droppings, nesting hens and lying up areas and are all frequently found on adder hibernacula and thermoregulation areas. Pheasants are even released on National Nature Reserves e.g. Whixall Moss in Shropshire, a sensitive bog heath habitat for wading birds, invertebrates and reptiles. Such rare sensitive habitats with declining species should be kept free of gamebirds and associated shooting impacts. To safeguard fragile species and habitats pheasants should be trapped and removed off wildlife reserves. Efforts should be made to prevent the birds from straying off shooting grounds.
The glut of gamebirds will potentially result in greater local concentrations of native predators including the common buzzard, carrion crow, magpie, fox and brown rat who will all predate adders. Corvids and rats are attracted to grain feeding areas in maize cover crops. Buzzards are a well known adder predator and the regular abundance of local pheasants, including plenty of roadkill, and climatic shift to milder winters influences predator survivorship, putting further pressure on already vulnerable reptile populations.
There needs to be much tighter regulation on pheasant release numbers. Landowners should have stock books to account for gamebird numbers, ideally having leg rings identifying a shoot to track roaming dispersal behaviours.
Remove and dissuade birds from nature reserves and important reptile landscapes and there needs to be greater research into pheasant impacts on herptiles.
The earnings from this industry are high,
but the actual importance of this game meat biomass in the UK food economy is
low. We are now much more conscious of ethical food production and carbon
footprints, but is this industry doing the same? Pheasants move between being under farming
regulations then switch to being wild birds with no regulations and no
monitoring of their affects.
I have been a rough shooter in the past, living off the land and growing my own vegetables, providing food for my family and only taking what I really needed, never a yearning to go on an organised pheasant shoot. This has now become a massive industry and far removed from the necessity of food for the table. Thousand bird shoots are there for those willing to pay.
The UK’s adders are slipping away, site carrying capacities low, optimal habitat limited and pressured. This once common snake is an indicator species to the health and quality of our wilder countryside. Surely preserving species and habitats should be a priority. Conservation bodies try to halt species declines but we need far reaching working associations, linking and improving the robustness of habitats and species where possible, not just for the adder but for our own continued future.
Landowners must prove they are real custodians of our wildlife and countryside heritage.
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I’ve seen pheasants on Brownsea Island which has a healthy population of common lizards . This is managed by the National Trust and Dorset Wildlife .
It’s infuriating these birds get everywhere !
It does seem that the Dundee Courier was still getting it wrong in 2017. Can we hope for better in the future?
As so often, an interesting guest blog. Thanks Mark and Nigel.
As with their coverage of the destruction of Monikie Curling Pond – The Courier tends to “not quite get it even remotely correct” so their play on “man bites shark” doesn’t surprise.
Here in Angus there are many areas near to me that would be a perfect spot for lizards and snakes if only there weren’t such an overwhelming density of chickens for the commercial bang-stick punters.. On the plus side; they feed the White Tailed Sea eagles.
There is a well known beauty spot near where I live where I used to see adders about 10-12 years ago, but I haven’t seen any recently.
The area is very popular with dog walkers, including ‘professional’ dog walkers who bring along several. The dogs are invariably off the leash and often out of control. There was for a while a series of articles in the local press about brave dogs fighting off attacks by poisonous snakes, having been stung.
Could unsupervised dogs be another reason for the decline of adders?
Yes, well the owners can be. I have met dog owners and seen posts online by dog owners boasting they will kill any snake they see to ‘protect they dog’ like its their duty.
There are probably disturbance issues too.
Not just adders but ground nesting and ground roosting birds. In fact, any mammal bird, reptile or amphibian that is unfortunate enough to be discovered by them. Not that you will get any dog owner to admit it.
Our local nature reserves all have restrictions for dogs: either on leads or banned. We have the signs stolen regularly and the number of volunteers / staff who have been insulted and even assaulted by dog owners is scary.
A very interesting blog and it is good to hear of someone championing one of our increasingly rare reptiles. I have been fortunate enough to see Adders in South Yorkshire and once you have had eye contact with an Adder you appreciate the beauty of these animals. They are the opposite of aggressive and you have to approach them so quietly to have any chance of watching them before they slink off to safety.
Once again the detrimental impact of releasing more than 50 million gamebirds is becoming increasingly obvious and urgently needs addressing.
Living in Oxfordshire and monitoring Warburg Adders since 1997 I can say that the population of EST. 25 to 30 snakes dropped to 1 in 8 years. I say a huge number of Pheasents from 2004 and found several mortaly wounded snakes and Slowworms. As well as birds Warburg became to busy and disturbed with refugia being regularly lifted. A great shame but I fear Berkshire seems to have several declining Adder populations as Pheasents and people disturb and kill them.
An excellent article, thank you Nigel.
Where I live on the Cheshire/Shropshire border the grounds if the estate where I rent a cottage used to have what appeared to be a healthy population if grass snakes and slow worms. I used to see them quite regularly but after 10 years or so of pheasant release-the estate leases the land to a gamekeeper who sells pheasant shooting days- I haven’t seen one for a very long time. Now I know why !
It took me a long time to see Adders anywhere, my first were during a long weekend visit to Norfolk. I did eventually find several places near home in North Yorkshire where one could find them in spring, these were on or on the edge of grouse moors and one always took care to try and ensure that keepers and shepherds did not find out as both are pretty anti Adder despite legal protection. One site was certainly discovered by keepers and the Adders there almost disappeared ( as did the accompanying Slow Worms- some folk are wilfully ignorant!) I know of several moors where keepers claim they have none or few because they kill them on site despite the law, but then they only seem to obey the law when convenient.
I’ve never seen a Pheasant attack an Adder but am sure that they do, I have seen them eat both newts and Common Lizard. Pheasants are a biodiversity nightmare and given it is impossible to stop them spreading into the wider countryside from release sites they should be classed as pests on all nature reserves and designated sites and legal removal or lethal control should be allowed. If Pheasants were identifiable to release site (compulsory rings etc) perhaps the originator of their release might be made to pay. My own view has for sometime been that all releases should be banned.
Excellent guest blog from Nigel who I’m fortunate to have met. He’s a mine of information on Adders and I’ve learned a great deal from him.
Adders have undergone a shocking decline, disappearing from many of their former sites, and now in many counties there’s only a few or no sites they are found now. Whilst as Nigel alludes to, they have long being persecuted, this rapid decline is more recent. It’s certainly coincided with the huge increase in Pheasant releases, from a few million in the early 1970s, to over 50 million now, a greater biomass than all British breeding birds put together.
It is quite absurd that this level of impact on our native biodiversity, where this biomass of alien species is released into the countryside every year – happens without any sort of oversight, proper regulation or impact assessment. It is just crazy. There are strict rules banning the release of other alien species and the fact that this loophole exists with Pheasants is almost certainly due to the fact that driven Pheasant shooting is a sport the upper echelons of the establishment engage in. It is institutional corruption when the laws, rule and regulations of a society are distorted in favour of a certain demographic which has unusual influence in our system.
Many of these Pheasants are not shot each year and they now widely disperse throughout the countryside and can be seen in large numbers all year around.
One of the shocking things is that the impact on our native reptile fauna of these Pheasant releases has never really been studied or assessed. It has been known for a long time that Pheasants definitely have an impact on reptiles. They are in the same family as Chickens, Jungle Fowl and have similar predatory habits toward reptiles. Yet for some reason this impact has never been examined and appears to have been deliberately excluded from assessments of Pheasant releases, I suspect very strongly due to lobbying from shooting interests who are only too aware of the impact i.e. that their release of Pheasants could be restricted or regulated if the impact was widely known.
Before any shooters come along and say not all those who shoot Pheasants are rich or in the upper echelons of the establishment, I am aware of this. I am referring to reason this glaring loophole as regards the usual regulations on the release of harmful non-native alien species exists.
And this loophole extends to planting out non native plants as cover for them mostly in our woodlands. The point is finally starting to filter through that in one hell of a lot of the sites where native flora and subsequently fauna have been choked out by rhododendron, cherry laurel, snowberry, cotoneaster, salmonberry, Japanese rose and others the source of it was planting to help keep pheasant cosy. This is a massive embarrassment for a shooting community that tries not to take any responsibility for this, something which makes their conservation credentials laughable. It’s a scandal when it’s realised that they’re STILL planting many of these species out. They deserve and need to be metaphorically drawn over hot coals publicly for this. They should be making amends for past mistakes not selfishly compounding them.
I don’t think dogs are the problem, it us, well they way we manage the land, organizations, landowners and councils are obsessed with the threat of public liability litigation, so we clear and manage the untidy bits. I firmly believe that the eradication of wildlife in this country is due in part to the affect of local extinctions.
The predation of reptiles by pheasant I have no evidence for, we don’t have that many, but, I have no reason to disbelieve it, especially after all that research. What evidence I have on this farm is that the kestrel and the two species of buzzard take their toll on the farms’ reptiles. Likewise the raven on our amphibians.
Local extinctions are difficult to quantify, as by and large it happens by stealth, or at least gives that impression.
We were contacted by the legal advisers of a multi-national corporate food chain, which was building nearby, would we take their reptiles and they’ll give us £15 grand for the trouble? We are happy to take them; the money didn’t bother us, until someone mentioned that it buys a lot of devils-bit scabious plants! What this illustrates is just a drop in the ocean, what on a larger scale is happening right through the country. The reptiles will go, now extinct from a plot they had chosen and occupied for goodness how long.
Part of the reason why this build is taking place is – travel west about 2 miles from the build and you hit an old diary farm, which had been sold and will shorty be 6000 new homes. This isn’t a small extinction but annihilation on an industrial scale. Now I expect at some time we’ll receive a very nice letter requesting if we want some more wildlife? We’ll need to carefully think about our reply, we are not these people’s convenient antidote for them to have a clear conscious on the destruction they are causing.
What should have happened is for us to have been allowed on the land before a sod of earth had been dug to sequester away beneficial plants and shrubs before the dozers moved – all paid for by the developers.
Two species of Buzzard, Thomas?
Yes, very lucky without doubt, Paul.
I have no experience of Adder / Pheasant interaction, but the piercing shriek of a Frog being pecked by Pheasant poults ( Toads bore it with silence if I remember), was quite regular, especially in release pens containing much long grass, favoured by the unfortunate creatures.
I used to place the rescued Amphibians in the water tank until I had finished feeding, then remove them to a boggy area of relative safety.
Adders, I am told, used to be frequently encountered on surrounding moors ( i can remember seeing the old signs warning the unwary of the great danger ), but are now rare.
In this case, management for Grouse was not an issue.
Cat Reid at the muir o’dinnet NNR writes a great blog which at this time of year features adders as stars of the reserve. Great photos too. Worth a visit for anyone local or on holiday
https://muirofdinnetnnr.wordpress.com/
I like the idea of ringing pheasants. Despite the judges views I think if you release something you should be responsible for its actions. Thinking of the headlight unit I had to replace.
I have seen two adders on our land in 30 years they had travelled 100s of meters on our land and I have no idea where the source population was. From what you say it seems likely they were males.
We have plenty of grass snakes; it is rare for visitors not to find one under one of the corrugated iron sheets. I think these sheets must be a great advantage protecting them from predators. Would they be useful where dogs are walked?
The protection must help our grass snakes. We can end up with 8 or more pheasants in the garden towards the end of the season attracted to the spillage from bird feeders. We take steps to remove them with live traps so there is only 2 or 3 left at the end of the season and when the snakes emerge.
Do adders use sheets, one visitor claimed to see an adder under a sheet but I am dubious as the grass snakes vary a lot in colour. Last year we had the first slow worm under a tin sheet.
If females are disinclined to travel you have a problem of natural repopulation especially with such a low reproductive rate.
I think we need to be less inhibited in our attitude to reintroduction and worried in case we fail and animals die. Those two adders I saw were taking a chance. Nature takes chances.
With all the effort in rewilding species which do not disperse easily are going to take a long long time to recolonise these rewilded areas and with a lack of corridors, never, without our help.
I’ve been arguing for a long time that all released Pheasants should have to be ringed to identify from where they have been released. This is such a simple measure, easy cheap and practical, that I do not understand why it is not a legal requirement. It would immediately make it clear which Pheasants haven been released as adults, and which are raised in the wild. It would also make it clear when you have large concentrations of Pheasants in area not within a shoot, where these Pheasants are coming from i.e. if there was an irresponsible estate just releasing huge amounts of Pheasants which disperse everywhere.
Adders do use these tin sheets, and slowworms and lizards.
I love that sentence about inhibitions, how right you are. I’m afraid rewilding is an uphill battle of media misrepresentation, fear mongering and ignorance.
Once a species has become extinct within an area (unless they can fly in, with the exception of black hairstreak, pearl, heath and marsh fritillary, who don’t move), I think you’ve pretty much had it, without lending a hand. That brings in the conflict of human interference, how much do you manipulate the situation? And for what purpose? Yours or financial?
What had annoyed me about the new house development, is that no one gave us a chance to see and locate whether there were any brown hairstreak eggs, rarer arable plants or if we can utilize the hedgerows. Our local Trust couldn’t be bothered to get involved either, and we work closely with them.
Excellent blog and some very good comments. One thing a dog is good for is chasing out uninvited pheasants from a large garden trying to increase the amphibious population.
Some time ago the Wiltshire Wildlife Trust tried an adder reintroduction to their reserve at Blakehill Farm. It is not a complete failure, as dead snakes are found from time to time. Virtually all fatalities show significant pecking damage. Just saying.