RSPB 4/F Second Rebuttal Proof of Evidence of Dr John Underhill‐Day for the Royal Society for the Protection of Birds April 2011 Town & Country Planning Act 1990 (as amended) In the matter of: Planning Applications for Construction of a runway extension and erection of a terminal building at London Ashford Airport, Lydd, Kent Planning Inspectorate Refs: APP/L2250/V/10/2131934 APP/L2250/V/10/2131936 1. INTRODUCTION 1.1 This rebuttal proof has been produced in response to the supplementary proof of evidence LAA/7/E submitted by Dr Roy Armstrong on “The predicted impacts of aircraft noise and visual disturbance on bird species of conservation importance near to London Ashford Airport (Lydd)”, referred to henceforth as the ‘SP’. 1.2 In this rebuttal, I have not revisited the issue of aircraft noise contours as these were fully explored in cross examination of Mr Perkins. 1.3 I refer only briefly to the available research on the effects of aircraft noise and vision on birds as this is covered in detail in my earlier proofs. 1.4 I summarise the approach taken by Dr Armstrong in the SP and outline what I consider to be shortcomings and inconsistencies in this. The lack of quantitive data on the birds noted in the SP as being found on or close to airports makes it impossible to comment in detail on the conclusions given. In many cases no numbers, locations or other detail is given. 1.5 I have, however looked in more detail at the evidence on aircraft noise and vision on reedbed birds as the SP makes some specific claims and these are of particular concern to the RSPB. 2. RESEARCH ON NOISE AND VISION 2.1 As noted in my main proof, the literature on noise and vision disturbance to birds from aircraft is limited with regard to species, relies mostly on studies of military jets and helicopters and does not specifically cover many of the featured species of the SPA/pSPA/Ramsar and SSSI (henceforth referred to as the SPA), at Dungeness. 2.2 The available literature makes clear that aircraft can have an effect on birds (see my main proof paras 10.57, 10.64‐10.67 & 10.73‐74) and that this can lead to adverse impacts (see 6.18 of my first rebuttal proof). Associated literature on vehicle noise has shown that birds will nest and feed close to busy roads but that there are impacts ranging from poorer condition of wintering birds, reduced breeding productivity and changes in breeding 1 behaviour, none of which would be apparent from casual observations. My view is that the evidence from peer reviewed papers and reports, covering a wide range of species, strongly supports the view that aircraft noise and vision effects can have adverse impacts on both wintering and breeding birds, although it is accepted that this can vary between species and locations. It also supports the view that simple presence of birds in areas affected by aircraft does not necessarily imply that there are no affects as assumed throughout the SP. 3. THE SP APPROACH 3.1 The SP has adopted the approach that where bird species have been recorded on or close to other airports the conclusion can be drawn that such species or in some cases similar species, are not affected by aircraft disturbance and will not be affected by the proposals at Lydd. This hypothesis is not supported by evidence. 3.2 Birds may tolerate a source of disturbance in order to find food or suitable habitat for nesting but this does not mean that there is no adverse impact. Studies such as feeding rates or nesting productivity on or in the vicinity of airports compared with the same measures on similar undisturbed sites elsewhere would be needed to demonstrate no effect. 3.3 Dr Armstrong states (the SP para 1.40) that he has not relied on the published scientific papers on the effects of aircraft noise on birds as he considers the "vast majority too simplistic or irrelevant", but he goes on to explain that he has nevertheless carried out a literature search for scientific publications and carried out other searches for general papers on disturbance associated with aircraft and aviation (the SP para 2.4). Apart from specific site related reports, the results of this search has resulted in the selection of a single scientific paper by Nisbet (2000) and a single report on disturbance distances (Ruddock & Whitfield 2007). The paper by Nisbet (2000) mostly concerns pedestrian disturbance to breeding colonial terns, and does not carry out any assessment of aircraft disturbance or a review of this issue, and the report by Ruddock & Whitfield is limited to a small number of breeding bird species of which the only featured species on the Dungeness and Pett Levels SPA is marsh harrier. 3.4 The SP refers to a paper by Frid & Dill (2002) and suggests this “summarised almost 100 papers in support”. This paper is concerned with developing a hypothesis that human disturbance is analogous to predation risk and explores this from an evolutionary 2 perspective. Of the 94 papers cited, many are concerned with human disturbance from hunting, tourism, boats, roads, all‐terrain vehicles, rock climbers, power lines and industry. Only 11 papers specifically relate to aircraft, of which 9 are concerned with aircraft disturbance to wild sheep, caribou and seals, and the remaining two are already before the inquiry and concern Mexican owls and responses of brant and Canada geese (Delaney, Grubb et al. 1999; Ward, Stehn et al. 1999). In no sense is this paper a review of aircraft disturbance. 3.5 Some groups of birds seem able to habituate to the presence of disturbance from aircraft. However, the same is true of busy roads, where research has shown significant effects including reduced densities and poorer breeding success in the noisiest zones. There has been only limited research on aircraft noise but displacement, changes in breeding behaviour, and a lack of habituation have all been found. Many authors have also cautioned that the results from particular species at particular sites cannot readily be applied elsewhere where conditions are different 3.6 For example, Burger (1981) found adverse impacts on herring gulls from supersonic but not subsonic aircraft, showing that breeding herring gulls, presumably well habituated to one level of noise disturbance could be seriously impacted by a new and different noise level and Brown (1990) noted that whereas crested terns seemed tolerant of aircraft noise, bridled terns did not. 3.7 The report on disturbance by Ruddock and Whitfield (2007) referenced in the SP, reviews a paper on marsh harriers disturbed by crayfish trappers. The authors concluded that breeding success was the same for disturbed and undisturbed pairs as measured by the number of fledged young, but that disturbed nest provisioning was seriously reduced and the young in disturbed nests were more malnourished. A number of studies have shown that young birds that leave the nest in poorer condition or later in the breeding season have a lower survival rate in their first year. 3.8 In none of the examples given by the SP have noise levels been measured, and apart from those cases where an aerial photo has been provided, no information is given on the species at most other sites, other than presence or absence, which do not allow any direct comparisons with the situation at Lydd. 3 3.9 In a number of examples the location given is for concentrations of birds close to airports on sites which are off to the side of the airport and well away from flight paths, and where it would be expected that noise would be attenuated and lines of vision obstructed. For example: 3.9.1 At Belfast the RSPB reserve is about 800 m off to the side of the runway with buildings and storage tanks in the intervening area. These attenuate the aircraft noise. See figure 4 of SP. 3.9.2 At Stansted, the balancing pond is about 1.6 km off to the side of the runway with buildings between the ponds and the runway, see map 1 (Appendix I). 3.9.3 At Heathrow, the largest balancing ponds are approximately 1.5km from the end of the runway and shielded by substantial built development from the airport, see map 2 (Appendix I). 3.9.4 At Coventry airport the water body is approximately 1km from the side of the runway and screened from the airport by numerous large buildings, see figure 5 of SP. 3.9.5 At Shannon, the water body is approximately 1.2km from the runway and screened by storage tanks and woodland, see figure 5 of SP. 3.10 All these examples suggest uncertainty about disturbance levels from aircraft and whether any conclusions on the possible effects on bird species at these sites are valid. 3.11 At Newcastle airport the SP gives peak numbers of teal 300, shoveler 35, tufted duck 150 and pochard 65 based on the 25 years old SSSI designation. However, recent WeBS data shows a significant decline in numbers for these species, as shown in table 1. It is not clear whether aircraft disturbance has been one of the main causes of this. Table 1 Species SP data from 1985 SSSI citation WeBS data. Highest peak count between 2004/5 and 2008/9 Teal Shoveler Tufted Duck Pochard 300 35 150 54 62 2 7 10 (source WeBS counts 2004/05 and 2008/09) 4 3.12 A number of other airports are mostly used by light or turboprop aircraft and not by the large jet passenger airliners proposed at Lydd. These include: 3.12.1 Sumburgh Airport Shetland, flying 34 seater turboprop aircraft.1 3.12.2 Stornaway Airport Isle of Lewis, flying 34 seater turboprop aircraft.2 3.12.3 Carlisle airport where no scheduled services have operated for many years and any proposals for expansion involve small turboprop aircraft.3 3.12.4 Fairford USAF airfield is used only by military 737 jets about once a week. No B52 aircraft have used this airfield since the Bosnia war.4 3.13 In all the above examples, there is little or no relevance to the situation at Lydd where the flight path to the south at Lydd will take passenger jet aircraft across the SSSI and Ramsar and down the western side of the SPA and pSPA, in places, within a lateral distance of 175‐200m of the designated European site. Aircraft arriving by this route will be flying at 200‐400m height alongside the SPA as they come in to land. 3.14 The proposed extension at Lydd will permit flights by jet passenger aircraft where flight paths are all over very open country, and where there are no trees, buildings or topographic features which will attenuate the noise or hide the aircraft from birds. A number of the other sites quoted (e.g. Belfast) are situations where the airport is situated in a noisy area with nearby motorways, boat traffic and heavy industry, Dungeness is a very quiet rural area where additional noise is likely to be far more intrusive. 3.15 For many of the species reviewed by the SP, little information is available. In all cases the conclusion that birds are highly tolerant of aircraft because they have been recorded on or close to airfields does not recognise the possibility that aircraft disturbance can interrupt feeding or result in higher levels of predation or lower breeding productivity. Birds choose optimal feeding and roosting sites in accordance with prevailing conditions. Disturbance may have a cost in terms of fitness or survival as I have noted in my rebuttal proof 6.18. 1
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5 3.16 The SP also gives other reasons for concluding no affects, including that there are alternative locations where birds, if disturbed, can go. The integrity of the site includes its whole area, and suggestions that birds can move somewhere else on the SPA, go elsewhere in the area or leave and return at another time are not adequate to avoid an adverse effect. The SP also suggests that birds can feed at night if disturbed by day. These matters have been addressed in my rebuttal proof (6.10, 6.22). 3.17 In relation to passage species the SP claims that particular locations are not important to them and if disturbed they can go elsewhere. Apart from the integrity point made above, for birds which are on migration, the need to feed to build up fat reserves to continue their migration, often for long distances and in the limited time available to do this, makes it important for these species to be able to feed in the most productive sites without disturbance. The SP also opines that some passage species should not be on the list of featured SPA species. However, the inclusion of such species follows a careful consideration of all the information available by experts, these species are included in the designations and therefore must be given full consideration as featured species. 3.18 The SP also claims that some populations will increase due to climate change (the reverse argument was used in Dr Armstrong’s rebuttal proof, section 2.2), or that they have already increased thus reducing their conservation significance, or are not likely to be present in significant numbers, or no longer breed and therefore will not be affected by the development. 3.19 I do not accept these as reasons for concluding that there will be no adverse effect from aircraft noise on these species which are present or could re‐colonise. 3.20 Where examples are given of birds which have become habituated to aircraft disturbance, perhaps because there are good feeding grounds or nesting areas close to the airfield, then one would expect measures to be taken by airport authorities to deliberately disturb them or to change the habitat to make it less attractive in order to move them elsewhere. If disturbance measures are effective and the birds are not disturbed off the area by one means they will be removed by another. 6 4. REEDBED BIRDS AND AIRCRAFT DISTURBANCE 4.1 The RSPB is particularly concerned at the potential effect of aircraft on reedbed birds. There have been no studies on noise effects on the birds of reedbeds including on any effects on breeding distribution, breeding productivity or the potential for increased predation. They are all species living in dense vegetation where they are unable to see potential predators (which from their perspective may include aircraft) approaching, but could be disturbed by the sudden onset of loud noise. In addition, all these species breed on the western edge of the reserve where the main reedbeds are located, and if displaced, have nowhere else to go where there is the same quantity and quality of habitat. These reedbeds currently extend to the northern edge of Hookers Pits (see Appendices to Mr Gomes’ proof Map 7). If disturbed, bitterns are just as likely to move rapidly through the reed beds on foot away from the source as to fly up. The same would apply to a number of other species which avoid predators by staying in dense cover. This makes it difficult to study the effects of disturbance on these birds, or to draw any conclusions from an apparent lack of visible response. 4.2 Bitterns are a rare breeding species which still has a small population at a very limited number of breeding sites, even though there has been some recovery from the extremely low numbers some 30 years ago. Purple herons have bred once in the UK at Dungeness and their future colonisation could be threatened by disturbance. The effects of aircraft disturbance on other reedbed birds are not known. The only study of which I am aware on a warbler species (Reijnen & Foppen (1991) found reduced breeding productivity as a result of traffic noise on a bird breeding in dense willow beds, a not dissimilar situation to Cetti’s warbler in reedbed scrub. 4.3 In his introduction to reedbed birds, Dr Armstrong reports (3.5.2) a light aircraft over Leighton Moss RSPB reserve, which is an area of extensive reedbeds with patches and lines of willow scrub. He reports (3.7) that this event did not result in any detectable response such as flights or calling, and goes on to say that if there was ordinarily such a response it would be well known to birdwatchers at the site. However: 4.3.1 The Senior Site Manager at Leighton Moss who has been there ten years and the warden who has been there 22 years both say they cannot recall ever seeing a low flying light aircraft over the reserve, suggesting this is an extremely rare event. It is 7 therefore to be expected that birdwatchers are not aware of any response from bitterns or other reedbed species to such an occurrence. 4.3.2 It is not surprising that Dr Armstrong did not observe any response from bitterns to this low flying incident as the reedbeds at Leighton Moss are extensive, the whole area cannot be seen from any single point, and indeed, when the reserve staff are carrying out coordinated observations for flying bitterns (to identify nesting areas) it takes five people in different locations to cover the whole area. If a bittern did fly up it is more likely than not that Dr Armstrong would not have seen it. However, as already noted, flying up is not likely to be the response of a bittern to an approaching predator. 4.4 The SP reports that no studies of the impact of aviation on any reedbed species could be found, and then suggests that if any of these species were of serious concern aviation impacts would have been studied. This statement takes no account of the fact that in the UK purple heron have nested only once in 2010 and that bitterns do not nest in close proximity to airports anywhere in the UK (see below). It is therefore not surprising that no concerns have been expressed until now, when a substantial airport extension has been proposed within a short distance of the nesting sites of both species 4.5 The SP (3.5.4) quotes Nisbet (2000) in relation to nesting herons, but Nisbet’s review of this group, as is made clear in a number of quotations given in the SP (e.g.3.5.4, 3.5.5), is of colonial nesting heron species and all of those referred to nest in trees or scrub, whereas both bitterns and purple herons are generally solitary species, nesting close to the ground in dense vegetation where disturbance conditions are quite different. 4.6 In 3.5.5 the SP notes, that “experience demonstrates that these birds are not disturbed by aviation noise and are highly tolerant of disturbance generally”. This statement is made without any evidence, other than the anecdotal report of overflying at Leighton Moss on which I have already commented. 4.7 The SP cites bitterns at Valley Lakes in Anglesey (3.7) and notes that they used to breed, that they were present during the breeding season 2010 and were therefore probably breeding. 8 4.7.1 Bitterns were last recorded breeding at Valley Lakes over 30 years ago in 1979, but the precise location is not known. 4.7.2 Bitterns did not summer or breed at Valley Lakes in 2010 according to the site staff on the RSPB reserve, although birds did winter in the area. 4.8 The SP goes on in similar terms to discuss aquatic warbler, bearded tit, Cetti’s warbler and water rail, observing that in the case of the last named, that “they are known to be highly tolerant to aviation activity”. Water rails and a number of other reedbed species including Cetti’s warbler are highly secretive, skulking species which are rarely seen even when known to be present. Any assumption that they are highly tolerant to aviation activity is unsupported by any evidence. Moreover, the notion that reeds will attenuate noise of passenger jet aircraft flying past at 200m distance (SP 3.9) is unsupported speculation. 4.9 In my opinion, this SP has not shown that there will be no adverse impacts at Lydd from the effects of aircraft noise and movement as a result of the proposals for the extension. 5. REFERENCES (References are already before the Inquiry). Brown, A. (1990). Measuring the effects of aircraft noise on sea birds. Environment International 16, 587‐592. (Referenced in CD1.23i). Burger, J. (1981). "Behavioural responses of herring gulls Larus argentatus to aircraft noise." Environmental Pollution 24: 177‐184. (Referenced in CD1.23i) Delaney, D. K., T. G. Grubb, et al. (1999). "Effects of Helicopter Noise on Mexican Spotted Owls." The Journal of Wildlife Management 63(1): 60‐76. (Referenced in CD1.23i) Frid, A. and L. Dill (2002). "Human‐caused disturbance stimuli as a form of predation risk." Conservation Ecology 6(1): art. no.‐11. (CD12.27). Nisbet, I.C.T. (2000). Disturbance, habituation and management of waterbird colonies. Waterbirds 23(2): 312‐332. (LAA/7/F, Appendix 3) Reijnen, R. & Foppen, R. 1991. Effect of road traffic on the breeding site tenacity of male willow warblers. Journal of Ornithology, 132, 291‐295. (RSPB 4/C, Appendix IV, Tab 16). Ruddock, M. & Whitfield, D.P. (2007). A review of disturbance distances in selected bird species. Report from Natural Research (Projects) Ltd to Scottish Natural Heritage. Natural Research, Banchory, UK. (CD12.41). Ward, D., R. Stehn, et al. (1999). "Response of fall‐staging Brant and Canada geese to aircraft overflights in South eastern Alaska." Journal of Wildlife Management 63: 373‐381. (RSPB 4/C, Appendix IV, Tab 22). 9 Map 1: Stansted Airport Appendix I Approx 1.5km Map 2: Heathrow Airport Appendix I Approx 1.5km