Wild birds: surveys and monitoring for onshore wind farms

Standing advice for local planning authorities, developers and ecologists for assessing the impacts of wind farms on wild birds.

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This is Natural England’s standing advice about protecting wild birds for local planning authorities, ecologists and developers involved in a single large onshore wind farm development.

All wild birds are protected by law. Some are protected by European law if they’re in a population that’s part of a special protection area and many are of conservation importance, eg there’s concern about declining numbers.

This guidance is mainly aimed at assessing and monitoring the impacts of wind farms on wild birds. You must specify what kind of monitoring you want to do and why you’re doing it in any application for planning permission for an onshore wind farm development.

Where it says ‘you’ in this guidance it means the developer or their ecologist.

Get more detail:

Decide if you need to survey

You won’t have to survey and monitor on the site if there’s no likelihood of an impact on species from a protected site or a protected species.

You’ll usually need to survey and monitor if there are birds from protected sites affected by the development proposal. This means if a significant impact is likely, eg where there is more than a 1% increase in background mortality numbers.

You usually need a survey and monitoring plan if the wind farm:

Wind farms, any installations connected to them and the staff that work there could lead to any or all of the following for wild birds:

  • loss of habitats through direct impact to the habitat itself or because of wild birds being displaced from feeding or roosting habitats
  • habitats being damaged
  • death because of collisions with any part of the wind turbines or any equipment associated with them
  • increased use of energy because of air resistance when there’s larger groups or rows of turbines

You should monitor the impact on wild birds after building wind farms to prove that mitigation has been effective and to provide information for future plans.

Who can survey

You’ll need to be an experienced ecologist, eg qualified, and you may need to be a licensed surveyor to survey and monitor wild birds.

Find an ecologist:

When you’ll have to do an Environmental Impact Assessment (EIA)

You’ll usually have to do an Environmental Impact Assessment (EIA) if one of the following applies to the wind farm:

  • there’s more than 5 turbines
  • it’s able to produce more than 5 MW
  • it’s next to a protected area
  • you have to do it because of the Habitat Regulations

When to survey and monitor wild bird activity

Survey and monitor bird activity before and after the wind farm is built. Use the same methods for both as the standards you use for surveying should be what you use for monitoring.

Important movements of birds can take place at any time of year but usually you should survey from:

  • March to July for breeding birds
  • November to March for wintering birds
  • March and October for passage birds

You should survey and monitor:

  • once every 2 weeks during the breeding season (you can use rings or other markers for breeding birds of particular conservation importance).
  • one or 2 visits a month for non-breeding birds
  • once a week for passage birds (at least twice weekly when migrating is at its highest)

Types of wild birds to survey and monitor

You should survey and monitor wild birds that are or might be sensitive to the effects of wind farms.

Identify wild birds

Before the wind farm is built, you should find out:

  • the species of wild birds that are in or near the site
  • how wild birds use the site or area around it, eg the parts of the site they use and when they use it
  • landscape features (‘topography’) of the site and surrounding area, eg valleys and cliffs

You might be able to get this information from any of the following:

Where to survey and monitor

You should survey and monitor either of the following:

  • the entire wind farm development site
  • a large enough sample of the site that can represent the whole site - you can do this if wild birds use the whole site in a similar way and their habitats are similar across the site

You should also include an area around any sample of the site (known as a ‘buffer’ area) if you’re only surveying part of the site. The size of the buffer will vary depending on the situation but usually should be from 500m to 2km in radius.

Use a reference area to compare your results

You should identify a nearby ‘reference area’ that’s outside the wind farm, not affected by it. Survey it before and after the farm is built, then compare results.

You may need to get permission to access the area from the landowner.

The reference area you pick should be as similar as possible to the wind farm development in all of the following ways:

  • habitat
  • topography
  • numbers and kinds of wild birds

What to include in your surveys and monitoring

Include all of the following information about wild bird activity in or near the wind farm development when you survey and monitor:

  • how they use it, eg nesting, displaying, feeding, roosting
  • how far wild birds are from the nearest turbine
  • what the weather was like where the wild birds were

You may also need to include:

  • flight direction and height
  • how wild birds behave when they’re flying, eg soaring, displaying hunting
  • direction and distance of the wild birds from the person who’s surveying and monitoring

If you have to survey and monitor at night

You might need to survey and monitor wild bird activity at night depending on the situation, eg including:

  • nocturnal migration
  • foraging activity by owls, nightjars, waders (eg golden plover), wildfowl

How to survey and monitor at night

You’ll need more time to do night-time surveying and monitoring because you’ll have to scan large areas from many different observation points.

You can use any of the following methods to survey and monitor wild bird activity at night:

  • thermal infrared imaging, eg photographing or digitally recording an image using a camera that tracks the heat given out by objects
  • radar monitoring, eg using horizontal and vertical radar to measure both flight direction and height
  • acoustic recording, eg using several microphones set in different directions to get information on where birds are and their flight height - this is particularly useful for measuring nocturnal migration of wild birds
  • radio-telemetryv- this means tagging and remotely tracking individual birds, eg by using GPS
  • night-vision imaging, eg powerful spotlights, night-vision goggles

You can also use these methods during the day if you’re surveying and monitoring remotely, eg using radar or video cameras so that human observers don’t affect any results.

How long you should survey and monitor wild bird activity

You should gather information about wild bird activity on the wind farm site and the reference area before and after it’s built - how long will depend on your situation.

Before the wind farm’s built

You should gather information about bird activity for at least one of the following:

  • 2 full seasons
  • whatever length of season matches the kind of bird you’re surveying and monitoring

You may need to gather information for a longer period than 2 years as bird numbers vary significantly from year to year.

After the wind farm’s built

You should gather information about wild bird activity for at least 5 years after a wind farm’s built.

You should gather information for longer and consider ‘adaptive management’ if the wind farm is found to have a major effect on wild birds of conservation importance.

You should also state the:

  • predicted numbers of wild birds that might be killed after colliding with wind turbines
  • factors that increase or decrease the risk of birds colliding with wind turbines, eg the design and location of turbine or the season

Collision risk assessments

You should assess the risk of wild birds colliding with wind turbines. Use fixed point or vantage point watches, eg a fixed position from which you can see as much as possible. Place vantage points outside the survey area if you can so you don’t disturb birds inside the survey area.

How to use vantage points to assess collision risks

Use vantage points to assess collision risks in the following ways:

  • cover an area from 100m to 500m beyond the perimeter of the development area, depending on the landscape around it, kinds of wild birds in or near the site and their habitats
  • are placed so that you can see and record wild bird activity across the site
  • in different weather conditions, eg clear, misty, rain, windy
  • during the day and at night, eg using radar or light-enhancing or thermal imagery
  • at different points in the tidal cycle depending on your situation

How much time to spend at vantage points

Use ‘timed watches’, eg observing birds over a specific period of time, to make the best use of vantage points. This should be a minimum of:

  • 36 hours per vantage point per season
  • 72 hours per vantage point per season for priority species such as birds of prey, otherwise known as ‘raptors’

Collision monitoring

It’s usually rare for a wild bird to collide with a turbine, but you should search for any dead birds and count any dead bodies you find.

Search for dead birds:

  • as often as possible, ideally every other day or at least once a week if there’s a lot of birds on the site
  • during seasons relevant to the kind of birds you’re surveying and monitoring
  • using a large enough sample of wind turbines - how many will depend on the size of the wind farm
  • for at least 3 years after the wind farm’s built
Published 9 June 2015