The Impact of Wind Farms on Moorland Birds in the UK

✅ KEY TAKEAWAY: Inappropriate moorland turbines displace birds and harm breeding success. True coexistence requires careful siting and strict mitigation to protect upland biodiversity.

Wind power is an important part of the global push towards low carbon energy, and the UK uplands are a prime site for such developments. These often windy and seemingly deserted landscapes can be an attractive option.

There are over 1000 onshore wind farms already operational in the UK, many of which are in the uplands. However, those who spend time on our moors will know that they are far from empty, hosting many bird species in particular that are threatened and struggling elsewhere.

Although wind power can offer a good source of clean energy, wind turbines must share the air space, and this overlap can have negative effects on birds in several different ways.

Worldwide, there is a large body of work looking at the impact of wind farms on birds, but not all these are relevant to the UK moorland environment. Some useful studies have been carried out on the UK uplands however, and important lessons have come from those.

Global lessons

In general, there are several ways in which birds can be affected by wind farms. These include:

• direct impacts through collision with the rotor blades.

• indirect impacts through habitat loss, disturbance displacement, or barrier effects.

Most papers agree that wind farms can have negative effects on bird species, with different risks to different groups – for example, high-flying, larger, less manoeuvrable species are at greater risk of collision with rotor blades, whereas those more averse to disturbance are more likely to be displaced during construction.

Lots of work has been done in Spain and the Americas looking at impacts on both migrating birds and large raptors such as vultures and birds of prey, finding that wind farms can have significant impacts for some species. Raptors are generally acknowledged to be most at risk from collisions with turbines, particularly soaring raptors. These species are often long-lived and slow to reproduce, so impacts on adult mortality can have a profound effect on local populations.

UK wind farms

Findings from studies in the UK and Ireland confirm that some of these themes also apply to our upland environments and species.

• Disturbance/displacement: this is the main mechanism for impacts on UK moorland species. The construction or presence of wind turbines can drive birds away from certain areas, essentially reducing the amount of habitat that is available for them.

• Direct collisions: while deaths due to collision with rotor blades do occur in the UK, the rate seems to be lower than that seen worldwide.

Displacement effects

On UK moorland, breeding waders appear to be most impacted by wind turbines. Several studies have found lower bird densities near to wind farm sites, particularly lower densities of breeding birds^1–3. For some species such as curlew and snipe, the construction phase of wind farms seems to have the most impact, with bird densities dropping during the building phase and not recovering afterwards.

The numbers

We know that several species have significantly lower breeding density within 500m of a wind turbine. One study published in 2009 looked at twelve moorland bird species and found that seven were affected by the presence of turbines. Across these species, the density of breeding birds was between 15 and 53% lower within 500m of the turbines, compared to further away. The effect was most marked for buzzard, hen harrier, golden plover, snipe, curlew and wheatear².

Findings from specific studies have shown:

• 79% fewer golden plover within 400m of turbines⁴.

• Declines in curlew (40%), snipe (53%), and red grouse during wind farm construction. Red grouse numbers recovered, but curlew and snipe numbers did not³.

• Habitat use by golden plovers within wind farm areas significantly reduced up to at least 200 m from the turbines, and breeding density lower than predicted at wind farm sites⁵.

• Total bird densities 0.3-1.3 birds/ha lower at wind farm sites compared to reference areas¹.

Focus: Hen Harriers

As a flagship species on UK moorland, and a focus for conservation efforts, the hen harrier is a species of particular interest when it comes to the impact of wind turbines. The WINDHARRIER project in Ireland has spent several years studying interactions between wind turbines and hen harriers, and has published a wealth of papers and information^1,6–8.

Wind turbines can affect hen harriers through collision risk, disturbance, and loss of foraging habitat, but current evidence suggests that although a raptor species, harrier collision risk is lower than might be expected. Perhaps because of their relatively low flight height, along with effective avoidance behaviour, hen harrier collisions with wind turbines are rare. WINDHARRIER finds a collision likelihood of 0.8-2.5 collisions over the 25-year operational lifespan of a wind farm.

However, additional findings from the project reveal that proximity to wind turbines decreases hen harrier breeding success by reducing both the proportion of successful nests, and the number of chicks per nesting attempt:

	Within 1km of turbine	Over 1km to turbine
Nesting success (proportion of nests to fledge a chick)	33.3%	56%
Productivity (number of chicks per nesting attempt)	0.78	1.23-1.55

There is as yet little evidence to understand the mechanisms for, or importance of, these effects at population level, especially when weighing up the contributions of wind power to a more sustainable future and the likely impacts of climate change on bird populations, including the hen harrier. Careful siting of wind farms will certainly contribute to successful coexistence between renewable energy and hen harrier conservation.

Mitigation options

Wind power is an important tool for the UK to reach its energy commitments, and as such it is important to understand how to limit the potential impacts of onshore wind power on local biodiversity, including birds, bats, and insects. Much work worldwide is focussed on how to mitigate this threat, including the French EU funded project MAPE (https://mape.cnrs.fr/). There are various approaches to reduce the risk posed to bird populations from wind turbines. These include:

Placement and site assessment

1. Logic suggests that birds faced with an object in their flight path must either avoid or collide. However, placing a turbine in a particular area does not always result in one of these outcomes – careful turbine siting to place them in lesser used areas, considering species flight height, common routes, eg between roosting/nesting and foraging areas, and landscape features such as steep slopes or ridges can all reduce risk to or impact on birds. Doing all we can to reduce the overlap between turbine sweep zones and areas that are heavily used by birds can minimise impacts^9,10.

2. Local landscape affects collision risk, especially for soaring raptors which use thermal air currents to gain height. For example, placing turbines on ridge lines or areas that birds use to gain altitude increases the risk of collision¹¹.

3. Careful analysis of the local bird population is critical. Siting turbines at or between nesting, foraging, roosting, or hunting sites is likely to increase collision risk. It is compulsory in the UK and EU to carry out bird surveys for potential sites before construction¹⁰.

Turbine characteristics

1. Greater rotor blade width and lower clearance to the ground both increase the likelihood of collision¹². However, these impacts can differ between species, for example raising the areas swept by the blades to reduce risk to some species may risk placing it in the flight zone of higher-flying species such as larger raptors.

2. Alterations to the turbine itself such as painting one of the rotor blades a contrasting colour¹³ or pattern¹⁴ has been shown to reduce collision occurrence by up to 70%.

3. Some turbines are fitted with automatic detection systems which identify birds approaching and react in a number of ways, including emitting an audio or visual deterrent, or stopping the rotor blades until the bird has left the area. These automatic detection systems reduce collisions, but they do still occur¹⁵. 

Conclusion

It is clear that poorly sited wind turbines can have negative impacts on some species of bird in the local area. However, mitigation options can minimise these effects, and turbine characteristics such as painted blades and automatic responses to bird presence can reduce collision risk even further.

It is mandatory in Europe and North America to take steps to mitigate the likelihood of impacts on bird populations from wind energy projects. Guidance is available from NatureScot.

We don’t yet know how significant these effects might be in the context of local or UK-wide species populations, but this is an important question as a small additional mortality can lead to significant population effects for some species¹⁶.

We are fully supportive of renewable energy solutions, and wind power is an important component of the UK’s energy mix, but it is important to fully understand the biodiversity impacts of these developments. We believe that wind power can coexist with successful local bird populations when turbines are well designed and carefully sited.

However, turbines located inappropriately, especially on sensitive moorlands can cause significant habitat displacement for ground-nesting birds and potential collision risks for raptors.

References

1. Fernández‐Bellon, D., Wilson, M. W., Irwin, S. & O’Halloran, J. Effects of development of wind energy and associated changes in land use on bird densities in upland areas. Conservation Biology 33, 413–422 (2019).

2. Pearce‐Higgins, J. W., Stephen, L., Langston, R. H. W., Bainbridge, I. P. & Bullman, R. The distribution of breeding birds around upland wind farms. Journal of Applied Ecology 46, 1323–1331 (2009).

3. Pearce‐Higgins, J. W., Stephen, L., Douse, A. & Langston, R. H. W. Greater impacts of wind farms on bird populations during construction than subsequent operation: results of a multi‐site and multi‐species analysis. Journal of Applied Ecology 49, 386–394 (2012).

4. Sansom, A., Pearce-Higgins, J. W. & Douglas, D. J. T. Negative impact of wind energy development on a breeding shorebird assessed with a BACI study design. Ibis 158, 541–555 (2016).

5. Pearce-Higgins, J. W., Stephen, L., Langston, R. H. W. & Bright, J. A. Assessing the cumulative impacts of wind farms on peatland birds: a case study of golden plover Pluvialis apricaria in Scotland. Mires and Peat 4, 01 (2008).

6. Fernández-Bellon, D., Irwin, S., Wilson, M. & O’Halloran, M. Reproductive output of Hen Harriers Circus cyaneus in relation to wind turbine proximity. Irish Birds 10, 143–150 (2015).

7. Wilson, M. W., Fernandez-Bellon, D., Irwin, S. & O’Halloran, J. The Interactions between Hen Harriers and Wind Turbines. WINDHARRIER Final Project Report. https://www.ucc.ie/en/media/research/planforbio/forestecology/WINDHARRIERFinalProjectReport.pdf (2015).

8. Wilson, M. W., Fernández-Bellon, D., Irwin, S. & O’Halloran, J. Hen Harrier Circus cyaneus population trends in relation to wind farms. Bird Study 64, 20–29 (2017).

9. Bright, J. A. et al. Spatial overlap of wind farms on peatland with sensitive areas for birds. Mires and Peat 4, 07 (2008).

10. Drewitt, A. L. & Langston, R. H. W. Assessing the impacts of wind farms on birds. Ibis 148, 29–42 (2006).

11. Péron, G. et al. The energy landscape predicts flight height and wind turbine collision hazard in three species of large soaring raptor. Journal of Applied Ecology 54, 1895–1906 (2017).

12. Škrábal, J. et al. Red kite (Milvus milvus) collision risk is higher at wind turbines with larger rotors and lower clearance, evidenced by GPS tracking. Biological Conservation 312, 111482 (2025).

13. May, R. et al. Paint it black: Efficacy of increased wind turbine rotor blade visibility to reduce avian fatalities. Ecology and Evolution 10, 8927–8935 (2020).

14. Hancock, G. R. et al. Biologically inspired warning patterns deter birds from wind turbines. bioRxiv 2025–04 (2025).

15. Gémard, C., Duriez, O., Chappe, O., Duclos, G. & Besnard, A. Towards a better understanding of avian collision in wind energy facilities using automatic detection systems. Journal of Applied Ecology 62, 1437–1448 (2025).

16. Schippers, P. et al. Mortality limits used in wind energy impact assessment underestimate impacts of wind farms on bird populations. Ecology and Evolution 10, 6274–6287 (2020).