A SPARROWHAWK MORTALITY INCIDENT AND POTENTIAL IMPACTS ON WILDLIFE FROM WIND TURBINES IN SUFFOLK

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A SPARROWHAWK ACCIPITER NISUS MORTALITY INCIDENT AND THE POTENTIAL IMPACTS ON WILDLIFE FROM ON AND OFF SHORE WIND TURBINES IN SUFFOLK TOM LANGTON The following is an account of what may be one of the first birds of prey killed by a wild turbine in Suffolk, together with observations on the difficulty of predicting the impact of wild turbine rotor blades on birds and bats.

Plate 13 shows a freshly dead Sparrowhawk found under one of the two large wind turbines at Kessingland grid ref approximately TQ 520 862 at 10 am on Sunday 16 October 2011. It was found under moving turbine blades on short grass about 40 m from the turbine main support base, together with its feathers spread around it to a distance of about 10 m, suggesting it was impacted from above and then dropped down. The wings were tucked into the body, that was in rigour mortis so it appeared to have been dead for a few hours but the neck was loose. The hawk had a fresh linear wound extending from the side of its back towards the back of its skull.

The wound had peeled back skin and feathers along the right hand side of its back, tearing the skin of the neck. At the anterior end of the wound the small pneumatized (air-filled) bones at the base of the skull on the right hand side were smashed. The injuries were also viewed using a digital veterinary xray machine. The main skull was intact suggesting that the birds head was in line with its back and looking down when it was hit from above. The circumstantial evidence of it being directly below the turbine blades added strong weight to evidence that the death was caused by a wind turbine blade collision, probably during low light levels of the early morning on that day.

The turbine blades would have been moving relatively slowly but my estimate was that the hawk flew towards the blades, perhaps from side-on and did not see the one that hit, descending in an arc from above at around 10 mph which seems likely to be sufficient for such a fatal hit.

Incidental observation of the wind turbines at the site over 2011 on a few other occasions suggests that one of the commoner birds that are present in the area; gulls, are aware of and react to the turbines on a daily even hourly basis.

There are two behaviours noticed. Those flying from a distance seem to see the turbine blades a hundred metres or so away and change trajectory to miss them by a clear distance. Others living and flying more locally may fly around and close to them and take last minute avoidance manoeuvres. They ‘dodge’ the blades quite frequently at least when the blades are moving more slowly, usually with some distance to spare. It is hard to think that accidents do not occur (much as gulls seem occasionally to be stuck by vehicles on roads) although the results of monitoring which was a condition of their construction (Triodos Renewables, pers. com.) are not known. It is reported that Peregrine falcon Falco peregrinus being flown by falconers at the nearby Africa Alive zoo, sometimes perch to rest at the top of the turbine towers. In general, wind turbines might be expected to be most prone to killing birds when birds do not see them descending at 10–90 km/hr (most birds look down when they fly), in the ‘8–10/2–4 o’clock zone’ although there seems little published on this. A Video of a vulture being struck at such a position can be found on the internet

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site ‘U Tube’. The Vet carrying out the x-ray of the sparrowhawk described a Buzzard in Navarre in Spain where she had worked being chopped into three pieces in one incident, the first blade cutting a wing off and the following blade its head. If a blade hits a birds head then the likelihood seems rapid death, if it hits a wing the bird may be disabled but not killed outright.

Matters for further consideration With a generally reported increase in many species of bird of prey in recent years, more wind turbine strikes are to be expected. With the recent shelving of government plans to reintroduce sea eagle Haliaeetus albicilla to east Anglia after the last general election, it must be observed that any such release or natural colonisation in coming years may be vulnerable to the larger wind turbines in the area. One of my colleagues living in northern Germany had a sea eagle killed by his villages wind turbine last year with a devastating impact upon the children and many adults in the area who had not fully realised the risk to eagles associated with the turbine.

Since the introduction of significant financial incentives for private land owners to generate electricity, a flurry of applications have been made to allow the installation of wind turbines in east Suffolk in recent years. Smaller 15 KW turbines with rotor diameter of around 9 metres have been in use for some time, for example one about 1 km east of Saxmundham along the B119.

The larger Ness point Wind Turbine in Lowestoft was completed in 2004 was Suffolk’s first commercial wind turbine, built by SLP Energy. It is 126 m (413 ft) high and generates 2·75 MW of electricity, enough energy to power 1500– 1600 homes. The Rotor diameter is 92 m (301ft) and each blade weighs 10 tonnes. In Kessingland two similar sized turbines were built in summer 2011

by Triodos Renewables.

It has been known for some time that wind turbines and the new cables required to remove generated power from them can kill birds and concerns about impacts on bats are not new (Betts 2006). Turbines may be warm due to heat generated and with their light colour attract flying insects that are prey for bats. Bats are inquisitive and will investigate moving objects. Turbine blades may simply attract bats towards them. Bob Stebbings has indicated to me that waving a long pole above your head is one way to attract bats and an old way of catching them was spinning a flat cap like a frizzbee and throwing it vertically – sometimes catching them underneath as it falls to allow inspection.

A farmer once asked me why bats are attracted to the whip aerial of his 4WD at night and this may be the frequency of sound created by the moving aerial.

More recently the killing of bats near turbine blades caused by sudden decrease in air pressure which can fatally haemorrhage their lungs (barotrauma) has been revealed (Baerwald et al., 2008).

The range of size in turbines and the variation in locations with respect to habitat types and bat densities has meant that there has been little consistent information and advice available and very little industry analysis and government advice until quite recently. The general industry position with birds is that turbines kill a tiny fraction of the birds that are killed by overhead lines, windows and cats and with bats that there is little or no information.

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A recent report by the Centre for Sustainable Energy concluded that out of every 10,000 bird deaths, less than one can be attributed to wind turbines, compared with 5,820 due to buildings and 1,370 to power lines, suggesting the wind turbine impact for birds is insignificant. The position has been oversimplified and is not informed by methods to determine bad locations for wind turbines and this makes a balanced approach more difficult. In fact turbine manufacturers should be conducting research in partnership with government as a part of the cost of their provision. There is an urgent need to identify sensitive zones within each County and to have local strategies to inform planning decisions. Such strategies at present are absent in any meaningful way for the species that are most vulnerable; those that are often or seem likely to be some of the more protected and rarer ones.

Concerns in the USA, Germany and Spain have been considerable but in Britain there has been little or no research. Worldwide there are several bad examples of turbine placement. In the USA, the Altamont Pass Wind Resource Area in California has been blamed for the reduction in numbers of six species of raptor and continues to record a high level of fatalities. The Smola islands off the north-west coast of Norway has one of the highest densities of the sea eagle/white-tailed eagle and was designated an Important Bird Area by Birdlife International in 1989. Between 2001 and 2005, 68 large wind turbines were built. Nine eagles were killed in a 10 month period and the population reduced from 13 to 5 breeding pairs. At two installations in the Campo de Gibraltar mountains in Spain, 63% of the raptor fatalities recorded are of griffon vulture Gyps fulvus, a protected species.

The regulator’s response Demand for wind turbine biodiversity risk analysis has greatly increased over the last five years and I have looked at seven locations in the east Suffolk area.

These are all outside the coastal area generally east of the A12 where the Royal Society for the Protection of Birds originally indicated a presumption against wind turbines. Work has involved principally research and surveys concerning bat and bird movements. To appraise potential impact this has included looking at the general policies regarding the placement of single or small numbers of turbines and mitigation which has been subject to a flurry of guidelines (Natural England 2009a, 2009b, 2010). These include recommendations to minimise collision through for example not placing turbines close to hedgerows and conducting bat surveys with sensitive recording equipment to determine regular flight lines.

Beyond considering the likelihood of collision for Biodiversity Action Plan species and those strictly protected under the European Habitats Regulations however there is no requirement for detailed studies and a general view of collison risk and impact only may be gained. For example, for barn owl Tyto alba, a species for which considerable conservation effort has been aimed in Suffolk as a regional stronghold , the general view is that they hunt below the lower blade tip height and vulnerability is greatest when flying higher to and from roosts with or without prey. For marsh harrier Circus aeruginosus, a species that forages inland for considerable distances from the

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coast however, the turbine blade heights are in the wrong zone. Almost completely impossible to judge however are the potential impacts on rare birds such as stone curlew Burhinus oedicnemus where mortality could be significant as rare events.

What has been missing from the general analysis is the vulnerability of rarer birds and impact on bats during migrations at every scale. While the industry analysis is right about turbines killing a low proportion of all mortalities, it is clear from overseas experiences that mortality can be significant if turbines are placed in positions where rare species may be most vulnerable.

The problem with the initial approach of sensitivity zones for birds is that they were ‘best guess’ approximations and not based upon specific research concerning bats and birds. With species of international interest involved what was needed was an analysis showing zones of highest and least likely impact on some form of meaningful scale. This needed to take account not only of local bat and bird populations but migration routes of both species.

Movements of birds and bats by day and night is little studied although technology now allows lightweight trackers to be used. Movement of bats between the UK mainland and Scandinavia that can even occur in winter is greatly overlooked. There has been insufficient study of the movement zones to prepare for wind turbine placements. This is typically due to reactive or response-based wildlife planning approaches rather than advanced or preprepared planning of a kind that sets out to protect rather than to attempt poorly informed compensation. This approach is characterised both by its cheapness and the lack of understanding as to what level of impact any particular action has. It leaves local authorities and government agencies the job of following guidelines to minimise any impact but without knowing what the overall impact of building a turbine any given location can be. There is also an expectation of mortality and that this is lawful, despite the obligation for European Protected Species (EPS) of showing in a quantitative manner that any mortality levels are insignificant.

Effectively the EPS approach necessitates a high degree of monitoring of strictly protected species mortality to make the process lawful in and to International Conventions that prevent indiscriminate killing and injury.

However, monitoring is hardly ever done to any serious extent and usually only for birds in general. In any planning applications in any areas other than those that might hold no or low risks, to be lawful there needs to be monitoring and a linked planning condition that should certain species are killed in sufficient numbers that the turbine is subject to refined controls (computers and radars now allow shutdown during certain weather conditions and times of day) or even removed. Turbine operators in parts of Spain now routinely keep a watch for migrating flocks and switch off turbines in their vicinity. Elsewhere a device DTBird detects birds in flight and sends a signal to switch off a turbine if a bird approaches within a given distance. There is however only one case that I could find of a turbine being removed due to an unacceptable level of bird mortality in the UK and that was a small 15 kw turbine and done voluntarily by the site owners.

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Monitoring properly is difficult and not dissimilar to monitoring road mortality of wildlife. On roads it has been shown that animals killed by vehicles at night are taken away by predators as dawn approaches and can sometimes be completely cleared away, masking mortality rates. The same is likely to apply for wind turbines where rats, cats, foxes and other predators learn where to find an easy meal.

The situation may not be helped by awareness of the need for an increase in energy generation from non-fossil fuel sources and a view that few wildlife downsides are an unfortunate side-effect. However with massive turbine placement underway offshore on the Suffolk and East Anglian coast in general there is the real possibility of some highly significant mortality for migrating bat and bird species. The London Array wind farm off the Essex coast, the Greater Gabbard scheme on the Suffolk coast off Ipswich (feeding power to Sizewell) and the massive Norfolk, Hornsea and Dogger bank projects amongst others may impact sea birds including rare and declining species such as the red throated diver Gavia stellata. Patrols of beaches and post-mortems might help detect mortality patterns but should each turbine have a form of radar system as well to accurately measure ‘chopdown’ rates? With countries pledging to recover many such species over the next ten years as a part of international undertakings, the implication is that significant compensatory measures will be needed and these need both to be identified and factored into the total scheme costs.

There is a feeling that local authority planners have been left isolated in their ability to protect vulnerable species as the law requires them to in their day to day duties. What is needed are County and marine plans showing good and bad wind turbine zones for bats and birds. It may be that some counties are good while others are no good at all. We need to know and the law requires us to know now. Planners might even be within their rights and required by law to refuse applications until such information is available.

References Baerwald, E. F., D’Amours, G. H., Klug, B. J. & R. M. R. Barclay (2008).

Barotrauma is a significant cause of bat fatalities at wind turbines. Current Biology, 18, (Issue 16, 26 August 2008): R695–R696.

Betts, S. (2006). Are British bats at risk from windfarms? British Wildlife 17: (part 5. June): 339–345.

Natural England (2009a). Natural England Technical Information Note TIN059, Bats and single large wind turbines: Joint Agencies interim guidance.

Natural England (2009b). Natural England Technical Information Note TIN 069, Assessing the effects of onshore wind farms on birds.

Natural England (2010). Making space for renewable energy: assessing onshore wind energy development.

Tom Langton Triton House, Bramfield, Halesworth, Suffolk IP19 9AE

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T. Langton Plate 13: Freshly dead Sparrowhawk found under one of the two large wind turbines at Kessingland (p. 55).