General Licences, Call for Evidence - SongBird Survival response

  1. On 4 May 2019, Defra called for evidence relating to stakeholders’ views on the alternatives to killing or taking a specific bird species for:

  • Conserving flora and fauna


  • Preserving public health or safety


  • Preventing serious damage or disease (serious damage relates to serious damage to livestock, foodstuffs for livestock, crops, vegetables, fruit, growing timber fisheries or inland waters) In particular, what are these alternatives and to which bird species do they relate? In your experience or evidence, how effective and practicable are they?


     and sought:

  • Experience and evidence of any benefits that were delivered by the 3 revoked licences, and:


  • Experience or evidence of any problems with or caused by the revocation of the 3 revoked general licences


  1. Our response is based upon views expressed by members, donors and other interested supporters who have contacted the Charity to date. Sadly, there has been insufficient time to consult, fully, all stakeholders due to the extremely short timeframe imposed.  Our response covers General Licence (GL) 06, for the purpose of conservation of wild birds and flora and fauna, as it relates to the conservation of ‘song and other small birds’, generally understood to encompass most birds of the order Passeriformes (that make up over half of bird species globally), excluding corvids (carrion crow, magpie, jackdaw and jay) that prey upon the others of the order, and the invasive, non-native, ring-necked parakeet that excludes native song and other small birds from supplementary garden feeding stations, and may outcompete them for scarce cavity nesting sites (Peck et al, 2014), (Strubbe & Matthysen, 2007 & 2009).


  1. Our response should also be viewed in the context of the fact that the density of Crows is higher in the UK than in any other European country, (5.15 pairs/km²), while the density of magpies in the UK is intermediate compared to other European countries (2.45 pairs/km²) (Roos et al, 2018). Of note, where predator densities are high, >5 corvid (crow & magpie) pairs/km² – species recovery, particularly of open-cup nesting species, may require predator control (Aebischer et al, 2015).  Meanwhile, both carrion crow and magpie populations have almost doubled, up by 98% & 97% respectively, over the period 1970 – 2015 and are ‘Green-listed’ (JNCC, 2018), while the Farmland and Woodland Bird Indices have decreased, markedly, down by 56% & 25% respectively, over the same period (Gov.UK, 2018). 


Conserving Flora and Fauna and Conserving Wild Birds 


  1. In most cases, there appear to be few realistic, practical and effective alternatives and no other satisfactory solutions to killing or taking specific bird species as authorised previously under GL 06. Where corvid density is high (Aebischer et al, 2015) and their presence ubiquitous (BTO, 2019a & 2019b), they soon become habituated to commonly-used deterrent techniques such as scarecrows, hawk-kites, gas guns, bird-scaring bangers, bird distress-call tapes, ‘flapping and shouting’ and other visual and noise-related deterrent strategies.  And in the latter case, it is impossible to sustain human deterrent presence and efforts 24/7, as would be necessary during the wild bird breeding season – being both too costly and time consuming, as well as ineffective. 


  1. Moreover, in urban and peri-urban situations, such techniques would be classified as anti-social, as would be the use of deterrent laser beams, gas guns, bird-scaring bangers, bird distress-call tapes or discharging of weapons to scare or deter problematic species. Similarly, corvid-proof netting around nest sites is likely to be very unpopular and unacceptable, as recent events with developers and the netting of hedgerows to exclude nesting birds has shown (Gov.UK, 2019).  Moreover, it may induce the species to be protected to desert its nest, and breed elsewhere in an unprotected and therefore more vulnerable site.  Consequently, all of the above methods are likely to prove counter-productive, in that they may deter the very prey species to be protected, from taking up territory and nesting, for the same reasons that they are designed to deter corvids.


  1. Additionally, for the jay in the forested, wood and parkland landscapes, use of such techniques are likely to be prohibitively expensive in terms of time and resources expended, and ineffective, for the same reasons as above. Research has shown that jays are one of the major predators of woodland-nesting song and other small birds, such as the Red-listed wood warbler (Mallord et al, 2011), and further as yet unpublished observations from a 2013 study in the New Forest attributed most cases of wood warbler nest predation there to jays.  The New Forest wood warbler population decreased by more than 50% during the period 2011-14 (has decreased further since) and has a 50% lower fledging rate than the national average (from a BTO AGM presentation, November 2015).  Furthermore, during research commissioned by the Charity into linkages between supplementary feeding of songbirds and associated nest predation in a peri-urban, parkland landscape, jays were found to be significant predators in an artificial nest experiment (28 out of 74 predation events), often associated with magpie and grey squirrel foraging activity.  This suggests that jays, being highly intelligent birds, associate feeding activity of other animals with the potential for food in the more general area (Hanmer et al, 2016).   


Experience and evidence of benefits delivered by revoked licence GL 06.


  1. Previous, largely correlative, reviews using national scale studies have suggested that positive local effects of killing or taking specific problematic wild bird species had little effect on national songbird population-levels (Newson et al, 2010), (Roos et al, 2018). Of note, this suggestion is undermined by Roos et al’s own finding, documenting a songbird increase in 40% of 20 studies employing experimental predator removal treatments.  Moreover, such national figures derived from opportunistic, observational-based studies may obscure important local patterns which could be critical for particular song and other small bird species and their populations.  And it is generally accepted that experimental removal studies are best in detecting an impact of predation on bird populations, and that findings from studies which use opportunistic data, for a limited number of predator species, should be treated with caution (Nicoll & Norris, 2010). 


  1. Recent experimental research commissioned by our Charity has revealed that properly targeted corvid removal does indeed positively impact local songbird populations. The results of this large-scale, 4-year, randomised corvid removal trial, using mainly Larsen traps, demonstrated increased farmland, hedgerow-nesting, songbird productivity, by 10% on average over 4 years, and by 16 % on average in 3 of the study years when the 2012 extreme spring weather that supressed both songbird and corvid productivity is excluded (Sage & Aebischer, 2017).  Set against the 56% long-term decline in farmland bird populations since 1970, this is an impressive result (Gov.UK, 2018).


  1. More recently, the Charity co-sponsored further corvid-related research, a PhD supervised by Professor Madden of Exeter University and Dr Sage of the GWCT, examining corvid predatory interactions (mainly magpies) with songbirds in the farmed landscape (Capstick, 2018). The Review section identified that 25% of reported songbird nest predation was attributable to corvids, with some species more prone to predation than others depending upon their nesting biology and breeding season, and that increased breeding success of such species can be achieved through targeted corvid removal; that some species may select sub-optimal nesting sites in order to avoid nesting close to magpie breeding territories possibly due to a ‘landscape of fear’ effect; and that during the peak of magpie breeding season, open-cup nests in magpie territories were more vulnerable to predation (simulated through the use of artificial nests as proxies for farmland hedgerow-nesting songbird species) (Capstick, 2018).


  1. Meanwhile, our Charity is currently contributing to a study assessing thrush breeding distributions and success in north-east Scotland at the Game & Wildlife Conservation Trust’s Scottish Demonstration Farm (GWSDF), comparing and contrasting results on the managed GWSDF with a neighbouring non-managed farm estate. Emerging findings from this study point to further evidence on the effectiveness of killing or taking of specific problematic wild bird species with respect to song and other small birds’ breeding success.


  1. Species likely to benefit from killing or taking of specific, problematic, wild birds include open-cup songbird nesting species such as the Red-listed spotted flycatcher, linnet, hawfinch, greenfinch, skylark, song thrush, mistle thrush, wood warbler, yellowhammer & whinchat and Amber-listed house martin, willow warbler, meadow pipit, bullfinch, dunnock & reed bunting, as well as other more common Green-listed birds.  

  2. Turning now to the invasive, non-native ring-necked parakeet (RNP), there is evidence of an exclusionary effect on songbirds at garden feeding stations (Peck, et al, 2014) and of the species outcompeting native hole-nesting birds for nesting cavities (Strubbe & Matthysen, 2007 & 2009). RNP breed earlier than many native species and are very aggressive in defence of nesting holes and cavities.  In our view, the RNP is in its 'break-out' phase with the population having reached critical mass in southern England and will, like many invasive non-native species, now rapidly colonise most suitable habitat in UK in the same way that the non-native grey squirrel spread post-1945.  For example, the species has already been recorded colonising suitable habitat as far north as Glasgow & Edinburgh (BBC, 2019).  Climate change will undoubtedly help its further, northward, spread. 

  3. As RNP effect on native species and agriculture is uncertain, and predicted/likely to be adverse (GB NNSS, 2016), the Precautionary Principle (European Commission, 2017) should be applied and RNP numbers should be controlled, generally, if it proves impossible to eradicate the species.  As is well known and widely accepted, acting too late with invasive species is always a very bad idea and much more expensive to resolve in the long-term. Species likely to benefit from killing or taking of this specific, problematic, non-native species include native hole and crevice-nesting song and other small birds such as Red-listed starling, spotted & pied flycatchers, lesser-spotted woodpecker; Amber-listed common redstart and other more common Green-listed species like the nuthatch – and non-songbirds such as Amber-listed tawny & little owl and stock dove.

Experience or evidence of any problems with or caused by the revocation of the 3 revoked general licences

  1. It is too early to tell of any problems with, or caused by, the revocation of GL 06 with respect to the impact on populations of vulnerable native song and other small birds, or to identify any conditions that could be attached to general licences to address these issues. However, the confusion, uncertainty, and exasperation experienced amongst land-owners, land managers and other conservation-minded Charity members has been profound and has shaken, deeply, previous confidence in Natural England’s ability and capability to manage, effectively, this vital pillar of conservation practice.  It will take much to regain and restore previous trust.


Aebischer, N. J., Bailey, C. M., Gibbons, D. W., Morris, A. J., Peach W. J. & Stoate, C. (2015) ‘Twenty years of local farmland bird conservation: the effects of management on avian abundance at two UK demonstration sites’ [Online]  Available at (Accessed 10 May 2019).

BBC News (2019) ‘Most northerly' parakeets cause flap in Glasgow park’ [Online] Available at (Accessed 10 May 2019).

BTO Bird Atlas Mapstore (2019a) ‘Carrion crow breeding distribution, 2008-11’ [Online] Available at (Accessed 13 May 2019).

BTO Bird Atlas Mapstore (2019b) ‘Magpie breeding distribution, 2008-11’ [Online] Available at (Accessed 13 May 2019)

Capstick, L. A. (2018) Variation in the effect of corvid predation on songbird populations. University of Exeter.

European Commission (2017)  ‘The precautionary principle: Decision-making under uncertainty’ [Online] Available at (Accessed 13 May 2019)

GB Non-native Species Secretariat (2016) ‘Ring-necked Parakeet, Psittacula krameri’ [Online].  Available at (Accessed 10 May 2019).

Gov.UK (2018) ‘Wild bird populations in the UK, 1970 to 2017’ [Online].  Available at (Accessed 10 May 2019).

Gov.UK (2019) ‘Make 'netting' hedgerows to prevent birds from nesting a criminal offence’ [Online].  Available at (Accessed 10 May 2019).

Hanmer, H., Thomas, R. L. & Fellowes M. D. E. (2016) ‘Provision of supplementary food for wild birds may increase the risk of local nest predation’ [Online].  Available at (Accessed 13 May 2019).

JNCC (2018) ‘The State of the UK’s Birds 2017’ [Online] Available at (Accessed 10 May 2019).

Mallord J. W., Orsman C. J., Cristinacce A., Butcher N., Stowe T. J. & Charman E. C. (2012) ‘Mortality of Wood Warbler Phylloscopus sibilatrix nests in Welsh Oakwoods: predation rates and the identification of nest predators using miniature nest cameras’ [Online] Available at (Accessed 10 May 2019).

Newson, S.E., Rextad, E.A., Baillie, S.R., Buckland, S.T. & Aebischer, N.J. (2010). ‘Population change of avian predators and grey squirrels in England: is there any evidence for an impact on avian prey populations?’ [Online] Available at  (Accessed 10 May 2019).

Nicoll, M. & Norris, K.  (2010) ‘Detecting an impact of predation on bird populations depends on the methods used to assess the predators’ [Online] Available at  (Accessed 10 May 2019).

Peck, H. L., Pringle, H. E., Marshall, H. H., Owens, I. P. F., & Lord, A. M. (2014) ‘Experimental evidence of impacts of an invasive parakeet on foraging behaviour of native birds’  [Online].  Available at (Accessed 10 May 2019).

Roos, S., Smart, J., Gibbons, D, W & Wilson, J D (2018) ‘A review of predation as a limiting factor for bird populations in mesopredator‐rich landscapes: a case study of the UK’ [Online] Available at (Accessed 10 May 2019).

Sage, R. B. & Aebischer, N. J. (2017) ‘Does best-practice crow Corvus corone and magpie Pica pica control on UK farmland improve nest success in hedgerow-nesting songbirds? A field experiment’ [Online] Available at (Accessed 10 May 2019).

Strubbe, D. & Matthysen, E. (2007) ‘Invasive ring-necked parakeets Psittacula krameri in Belgium: habitat selection and impact on native birds’ [Online] Available at (Accessed 10 May 2019).

Strubbe, D. & Matthysen, E. (2009) ‘Experimental evidence for nest-site competition between invasive Ring-necked Parakeets (Psittacula krameri) and native Nuthatches (Sitta europaea).’ [Online] Available at (Accessed 10 May 2019).