Wednesday, 7 March 2012

A New Future for Post-Construction Wind Farm Monitoring?

Post-construction surveys at operational wind farms are an essential part of the on-going monitoring that all wind farm developers should undertake. The monitoring protocols are recommended in guidelines for wind farm surveys published by Scottish Natural Heritage (SNH 2010)[1] and Natural England (NE TIN069, 2010)[2].

Reasons for Post-Construction Monitoring

Post-construction monitoring is an integral part of wind farm survey protocol and is primarily used to test the accuracy of pre-construction survey methods and assessment and to ascertain whether there are any unforeseen impacts of an operational wind farm on birds and bats. In addition, whilst the methods for wind farm assessment are robust they need to be constantly monitored to keep them up to date.

The methods used in the UK to assess the impacts of collision mortality on bird’s uses a theoretical Collision Risk Model (Band 2005). This model is not flawless and when devised assumed that birds would largely avoid operational wind turbines, in the same way that birds generally avoid other structures such as buildings. The avoidance rates were, at the time, a ‘best guess’ and this is one area in which post construction studies have increased the knowledge of the true effects of operational wind farms on birds. 

The original avoidance rates were estimated at approximately 95% for most species however as a result of post-construction studies most have been revised up to between 98% and 99%. There are a couple of exceptions, such as White-tailed Eagle and Common Kestrel, which appear to have worse avoidance rates than other similar species and remain at 95%. In essence for most species this means that the model assumes that between 98% and 99% of flights within a wind farm area will avoid the operational turbines.

Post-construction monitoring will usually involve a repeat of pre-construction surveys as well as completing carcass searches. These searches are very important to show the true number of birds and bats that have collided with the operational turbines. 

Carcass Searches
At present surveys involve walking linear transects within a search area around each operational turbine looking for bat and bird carcasses, with surveys normally completed every 7 – 14 days (Drewitt and Langston 2008, Lucas et al. 2000 and Osborn et al. 2000). These methods are very time-consuming, impractical and biased as they rely on visually searching an area that greatly depends on the skills of the observer, the size of the carcass, vegetation cover and topography (Drewitt and Langston 2008).

Bats are generally found within an area half the length of the turbine tower however bird carcasses are found over a larger area; usually up to the length to turbine tip. With the advent of new larger more powerful turbines this can mean search areas up to 9.0 ha, which can take a staggering 9 – 10 hours searching by a trained ecologist. That equates to a single days work just to search one turbine.

A study at operational wind farms in Portugal was completed in 2011 where specially trained dogs were used to search for carcasses. The findings supported previously completed trials and were quite eye-opening in terms of both searcher efficiency and detection rates (Paula et al. 2011). This should also be good news for wind farm operators as increasing efficiency of post construction surveys will have a knock-on effect of reducing costs. The dogs were shown to increase efficiency rates of between 4 and 12 times, therefore increasing the speed of the surveys per turbine and detection rates of almost 100% in all habitat types. Detection rates for human searchers were as low as 10% in tall, denser vegetation.

Dogs really are the way forward for completing carcass searches in terms of both providing a cost effective service to clients and increasing the validity and value of post-construction surveys. This latter point will increase the robustness of pre-construction assessment processes and serve to enhance the‘green’ credentials of renewable energy. 

The Future is Bright –It’s Liver and White

Back in August 2011 Turnstone Ecology bought a Clumber Spaniel puppy in order to train her as a specialist search dog for operational wind farms. Named Luna (which was not intended to be short for Lunatic but is quite apt!), she is now 7 months old and we’re waiting for her first season and then search training will begin in earnest. Currently she’s being trained to the whistle and various hand signals but she already covers the ground very well and seems to have a very good nose; mostly for chocolate, plastic or anything chewable! The blog will be kept updated with her progress.

In the mean-time we have contacts to other dogs with the ability to complete post-construction studies, which will assist in passing on the cost saving that the efficient searches provide. Alternatively we can continue to do them the old fashioned way.

Turnstone Ecology has experience of both pre- and post-construction wind farm studies, including activity and vantage point surveys. We are constantly looking for innovative ways of making the process of planning such developments simpler and more efficient and have recently developed a model (based on Band 2005) that assists us with the Collision Risk Assessment process. This allows for the changes within turbine layout and removal of turbines to be reflected within the output of the Collision Risk Assessment and saves both time and costs within what is always a highly iterative process.

If you are planning a new wind farm project or need some advice or assistance with an operational wind farm we would be delighted to hear from you.Please contact us at for further information.

Wednesday, 18 January 2012

Happy New Year

Looking Back at 2011 and Forward to 2012

Happy New Year.  A quick review of an exciting end to 2011 and a look forward to what will hopefully be another successful year in 2012.

Before the main 2011 survey season came to an end we were lucky enough to be involved with a couple of interesting projects in the UK.  The first was a leisure development in Shropshire where we'd already found and mitigated for Dormouse but needed to complete appropriate bat mitigation under a Natural England licence.  After bat boxes had been erected and a specially designed bat loft incorporated into the site's new machinery shed it was time to exclude bats potentially roosting in buildings set for demolition.

During the exclusion and demolition five Soprano Pipistrelles were found behind a door frame and successfully relocated to nearby bat boxes.

November 2011 also saw the conclusion of a successful Badger exclusion in Staffordshire. After evidence of Badger activity had been recorded around our previously constructed artificial sett (see blog post - 7th June 2011) the exclusion process was completed under Natural England licence and demolition of the majority of the natural sett soon followed.

Inside the sett
Prints in artificial tunnel entrance

Once the natural sett was demolished back to the boundary fence, chain link was fixed along the bank to prevent access to open holes and deter Badgers digging back in to the subsequently landscaped bank.  Gates and chain-link were removed from Badger holes on the other side of the fence and Badgers are now free to use these once again. 

In October 2011 Turnstone Ecology were commissioned to assist with the assessment of a proposed wind farm in Mainland, Orkney.  The fieldwork is being completed by local ornithologists  and we were able to complete a visit to the site at the end of November.  In addition to familiarising ourselves with the site and meeting the client we were able to do a little birding around this very beautiful island. 

The Ring of Brodgar
The journey to and from Orkney was fairly eventful.  On the way north we had a stop over Stirling where we very nearly got flooded in!  High winds and rain followed us up the road - but did abate enough for Tristan to have a 'life tick' (Crested Tit) at the RSPB Loch Garten reserve.  The boat across to Orkney was a little bumpy to say the least.  We had a two day break in the weather whilst on the island which was very well received by all - especially when completing field work!

Adult Iceland Gull
We managed to do a little birding on the final day on the island - the highlight was an adult Iceland Gull in Stromness Harbour (best loaf of bread I've ever purchased!).  We also had very good views of Black Guillemots, Eiders and Purple Sandpipers.  Mark even managed to break 200 birds seen in a single year!

Black Guillemot
Male Eider

The return journey was fairly uneventful other than a little snow and ice in the Highlands however it transpired that we were very lucky to get off the island as the boat we caught was the last boat to leave Orkney for a couple of days due to very high winds and rough seas! 

Looking forward to 2012 where we will hopefully return to Orkney to complete surveys on one of the most northerly bat populations in the UK. 

2011 ended with Turnstone Ecology increasing our International experience with survey work and site meetings in Galati, Romania and a review of the Polish Guidelines Concerning Impact Assessment of Wind Power Stations on Birds for the Polish Wind Energy Association (PWEA).

After a long but fairly straight forward trip out to Galati, eastern Romania, we completed a site assessment of four proposed wind farm projects and met with local ornithologists who have been undertaking intial survey work.

Syrian Woodpecker

White-tailed Eagle mobbed by corvids

Following our highly commended review of the Polish Wind Farm Guidelines we were invited to Warsaw to speak at the PWEA 13th Wind Energy Forum .  Not a birding trip, so no pics, but an excellent and valuable experience and a good way to finish 2011.

We are all looking forward to another busy year of ecology surveys.  Timing of these surveys is critical as many are very constrained by the season and/or guidelines and it is possible that the results of surveys may not be accepted if completed outside of the guidelines.  We have included an abridged version of the ecology survey calendar.
Type of Survey
Phase 1
Site Initial Ecological Assessments
Great Crested Newt

Presence/Absence Surveys


Presence/Absence Surveys


Nest Box/Tube Surveys
Nut Search
Sett Surveys
Sett Exclusions/Disturbance



Surveys conducted all year but limited by high water levels
Water Vole

Peak months- April, May and September

If you are planning a development (large or small) in 2012 please bear in mind the survey seasons.  If you require any more information or would like us to provide a fee proposal for any works please contact us -

Tuesday, 9 August 2011

Happy Birthday Turnstone Ecology

Today is exactly one year on since the first working day of Turnstone Ecology! It has been a great year for us and in truth much more than we had hoped for from our first year of business. 
We’ve had the opportunity to work with some good clients and some old friends and colleagues on a real variety of interesting projects. In the last twelve months we have surveyed for and found a wide range of species including Great Crested Newts, bats, Dormice, Badgers, Otters, Pine Marten, Red Squirrel, Water Vole and all the commoner Reptile species as well as a variety of ornithological jobs.
Along with winter and breeding bird site surveys across the country our bird work has also included wind farms in the UK and abroad, surveys of a pSPA to provide management advice associated with new public access and a watching brief of a Peregrine Falcon nest; which saw two juvenile Peregrines successfully fledge. We have worked on a variety of job sizes from small individual housing developments to large international wind farms and have really enjoyed the variety of challenges that comes with each.

We would like to extend our warmest thanks to everyone who has been involved in the first year of Turnstone Ecology. So many people have helped along the way and it’s not possible to list them all!This has included huge help in starting up the business to the odd simple words of advice and encouragement along the way and all of this has been invaluable to us – we hope that all those who have helped know how grateful we are for their time, energy, effort and support.

 We look forward to our second year as a company and already have a lot of exciting work lined up. We are expecting that Turnstone Ecology will continue to grow, becoming involved with new clients and projects and adding to the team of experienced ecologists.
Tristan, Steve and Mark

Tuesday, 7 June 2011

A New Home For Badgers

Turnstone Ecology were recently commissioned to create an artificial badger sett.  The sett  was created as later in the year a main (and currently used) badger sett will need to be closed to allow a permitted development to continue.  The sett will be closed under licence issued from Natural England and the creation of an artificial sett is central to this licence application and mitigation plan.

The new sett is located in a quiet corner of a future public open space area and had to be created in an area of open ground which was flat.  The flatness presented a slight problem but with a bit of earth-moving a two-tier mound was created; in to which plastic pipes and chambers were placed.

Due to the flatness of the area in which we were asked to create the new sett a lot of earth moving was required.
 Once the initial ground works were complete the pipes and artificial chambers were set out.

We created two larger chambers that had one or two 'open' sides which will hopefully encourage any badgers using the new sett to dig their own tunnels and chambers.

The central area between the two tiers has been left free of pipes and chambers and the hope is that this area will be 'dug out' naturally.

 Close up of one of the large central chambers.  The open sides were closed off slightly before filling in with top soil/spoil but large gaps were left to encourage the creation of natural tunnels and chambers.  The chamber was stuffed with fresh hay.

The picture (left) shows the final layout of the 'top' sett. All of the chambers were filled with soil and had a maximum of three pipes leading in to or out of the chamber.

Two-tiered artificial badger sett

Once all the initial earth-works and setting-out had been completed the final stage of the process was to cover the whole lot in approximately 1.5 metres of soil to create a large artificial earth bank.  Once completed the areas around each of the pipes was dug out (to allow any badgers to find the tunnels) and a layer of sand placed outside each entrance hole.  The sand layer is placed at the entrance holes to allow us to monitor any usage of the new sett by badgers. 

Landscaped mound showing new entrance hole.  The hole has a layer of sand at the tunnel entrance and we have scattered some fresh hay/bedding material on the 'spoil' heap.  Care has been taken to create as natural an entrance as possible.

The artificial sett will be regularly checked to look for any signs of activity and we will update our blog with what we find.

Final shot showing the finished spoil heap with a bespoke artificial badger sett.  The sett is located in an area in which the badger clan are known to forage and it is hoped that the new sett will be used very soon. 

The artificial sett will be regularly checked to look for any signs of activity and we will update our blog with what we find.

Friday, 14 January 2011


Waxwings have continued to entertain many birders and non-birders during the first few weeks of 2011.  Although the larger flocks have now headed to the south of the country and over the channel to mainland Europe there are still small numbers scattered all over the UK.  After many weeks of trying to track down birds in and around Shrewsbury, and only managing a brief distant view of 17 birds from my study (right), I was lucky enough to catch up with a small flock in the east of town.  

Up to 31 birds were present in trees in a quiet residential area, an unusually pleasant area for Waxwings that are usually found in retail parks, along road verges and a few weeks earlier on a roundabout along the A5!  The sun was out and the birds gave cracking views as they came down to feed on a single Rowan tree in a front garden.

    Favoured perching tree prior to flying down to berries on a Rowan

    Feeding frenzy

    The breeze played havoc with their hair styles!

After reviewing a couple of shots on the cameras LCD screen I realised there was one Waxwing with a number of rings on its legs.  A quick search on the web when I returned home revealed that the white ring and standard metal ring on the right leg indicated it was a bird ringed by the Grampian Ringing Group so I sent them an email with the combination of three coloured rings on the left leg. A quick response showed the Waxwing was a 3rd year male ringed in Aboyne, near Aberdeen in early November and subsequently seen by another birder in Manchester at the end of November. 

Ringing provides interesting and valuable information on bird movements so keep an eye out for ringed birds when looking at flocks of Waxwings and other species. More information can be found by following the links below:

Friday, 7 January 2011

Happy New Year ………………. Spare a thought for the birds!

Happy New Year to one and all from Turnstone Ecology!
Its been a great few months for Turnstone Ecology and this is always an exciting time of year, the snows been a real feature of the festive period and it makes for great photos but spare a thought for the birds........
During the winter our birds act a lot like ourselves; some disappear to warmer climes, some remain here to tough it out and others (such as the thrush flock pictured to the left) come from even colder areas in search of food. For those birds on our shores throughout the winter finding food and making sure they keep their energy up to survive is their greatest test.
Studies by the British Trust for Ornithology (BTO) showed that the cold weather over last winter (09/10) resulted in significant population declines for many resident bird populations. In particular the numbers of Robin and Wren fell along with a decline in numbers of Dunnock and Greenfinch. In contrast the study showed that our migrant species fared much better with Blackcap, Common Whitethroat and Reed warbler numbers higher than average and many migrant species produced significantly more nestlings than in recent years.

For birders who have started their 2011 lists in the last few days the cold weather has ensured we start the year with large flocks of winter birds that have been pushed into the country from north ern Europe in search of food. This winter has seen higher than usual numbers of winter visitors driven in by cold northerly winds with large flocks of typical winter visitors such as Redwing and Fieldfare being joined by scarcer species such as Northern Long-tailed Tits, Arctic Redpolls and what seems to have become this winters speciality… the Waxwing!

Waxwings typically arrive in the UK at the start of winter from their summer breeding grounds in Scandinavia, usually present in only small numbers in northern and eastern UK. The birds are immediately on the hunt for our berry trees and bushes, with Rowan a particular favourite, and with the numbers of berries already dwindling by the time of their arrival the flocks often move inland to find food, ending up in orchards, shop parades and superstore car parks.

Flocks of waxwings are usually in the tens but have been recorded at a peak of over 600 in Scotland this year with estimates of over 2500 individuals in the UK this winter. Turnstone Ecology’s winter record is a flock of around 150 in Peterborough but with the influx this winter they have been recorded in the vicinity of all of our offices.
Whilst we can only really offer food sources for Waxwing by planting berry trees and bushes we can all do our bit for other species in hard winters such as this. Top tips for feeding birds and helping them through the winter can be found from the RSPB at
Just remember that by providing food and water in our gardens when times are hard we can often get better views of more secretive and scarce birds .
Good luck for the new year, get those lists ticking over and enjoy the last few weeks of our winter visitors.

Other interesting links on our wintering birds below:

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Saturday, 18 September 2010

Leach's Petrels on Migration

Following on from a weeks very hard work in Wrexham we decided to head off after work to New Brighton for a spot of sea watching.  Over the preceding four days very strong north-westerly winds had brought a large number of usually pelagic species very close to the shore and birdwatchers had been lucky enough to get very good views.  It was an opportunity to observe a migratory phenomenon whilst having a catch up with a former colleague (Tom) who is lucky enough to have New Brighton as his local patch!

We drove straight to the car park at the Perch Rock lighthouse and were informed by Tom that he had just observed seven Leach's coming out of the mouth of the Mersey and were battling against the wind to get back out to sea.  Within a couple of minutes we all had very good views of (what was for me my first ever) Leach's Petrel.  A single Black Tern was also recorded fighting against a very strong head wind.  We decided to move location and headed for the Old Fort on the North Wirral Foreshore to see what we could see and were all rewarded fantastic views of Leach's Petrel.  No Sabine's Gull today but the petrels made up for this with an amazing display and some got very close.  In the space of 30 minutes we are sure we were being passed by up to two birds a minute and at times it felt like more.  Very distant views of an unidentified Skua sp. and Shearwater sp. added to the excitement - it was just a shame that they were so far away and identification couldn't be confirmed.

Here are a couple of pictures and the state of the sea should give an indication of how windy it was.

These birds were just dancing over the waves and were occasionally seen 'running' on the surface of the water where they pick up small food particles.

It is amazing how such a small bird can fly so strongly in to such head winds

Such an amazing late-afternoon at one of the best spots in the UK to observe this species.  Leach's Petrel breed in the United Kingdom with much larger numbers in Greenland.  With very strong north westerly winds they are 'funelled' through the Irish Sea and can be seen in large numbers on the west coast of England and Wales (as was the case this week).

It was nice to see a free-flying (over the waves!) petrel, I have seen a few European Storm Petrels in the past by only in the hand - in fact my first ever 'Stormy' was a Portuguese ringed bird re-trapped on Hoy, Orkney.

More interesting stuff to follow including trip report from Turnstone Ecology's first Bulgaria trip (August 2010) and our soon to be second trip to the same project; I am jetting off on Tuesday 21st September for a very quick audit of a field team who are completing vantage point surveys for a proposed wind farm.