Displacement & Collision Risk – Birds

Annex  – Displacement & Collision Risk – Birds



Natural History Society of Glasgow published in 1908 Charles Berry’s The Birds of Lendalfoot in which he identified 162 species of birds habitually seen within four miles of Lendalfoot with 78 species breeding in the vicinity.  That work regularly refers to bird species which he is observing at Lendalfoot as being from Ailsa Craig which is consistent with modern times when gannets are regularly seen feeding close inshore off Lendalfoot. A spectacular sight.


Ailsa Craig is of course an SSSI and Special Protection Area in respect of sea bird colony and breeding and sea bird assemblage.


What is clear from observation evidence is that the very healthy bird population which Lendalfoot has always enjoyed has increased significantly since the advent of the Landfill site at Straid Farm. There is a large bird population established in the vicinity of Straid Farm largely comprising sea gulls that roost on Straid Farm, on the beach to the west of Straid Farm.


The bird population at Lendalfoot has evolved in recent years to give two distinct groupings. Those birds in the habitat, both land and sea, living very much as nature intended and the very substantial colonies of urbanised seagulls drawn to and living off the landfill site.


There have been a number of research papers published on the effects of wind farms on bird populations.


Displacement is recognised to be one of the principal impacts which windfarms have on bird populations both during the construction and operation phases of the development. It is generally recognized and accepted that :-


  • The effects attributable to windfarms and the scale of displacement vary greatly from species to species.


  • Disturbance arises from human activity during construction and maintenance and the presence of and noise of turbines which deter birds from areas close to the turbines.


  • Disturbance can lead to displacement and exclusion from areas of suitable habitat, effectively loss of habitat for the birds


  • There are several reliable studies which demonstrate negative effects up to six hundred metres from turbines i.e. reduction of bird use or absence from the area close to the turbines.
  • ·
  • The area of exclusion refers to an individual turbine and the cumulative effect will be that birds face exclusion from a significant area.
  • ·
  • Turbines may be a barrier to bird movement so that birds would fly round an entire cluster of turbines which may lead to disruption of the link between feeding, breeding and roosting area.


  • More recent studies on gannets, guillemots and razor bills occur in lower numbers within 2 and 4 kms of a windfarm


  • Birds tended to stop nesting within half a mile of any turbine.


  • Since the effect extends around each machine, up to two square miles could be affected by one turbine


  • Studies at Nysted, Denmark which took place over a seven year period show that birds start to divert their flight paths up to 3km away in the daytime and 1km away at night. This avoidance represents a habitat loss and the abandonment of suitable habitat.  Displacement of birds however reduces collision risks.


Collision Risk and Mortality are recognised impacts on bird populations as a result of windfarm developments


  • Studies have shown that collision mortality rates are low but the information is usually collected by reference to corpses found leading to under recording.
  • ·
  • For some bird populations which are large bodied, long lived species (many sea birds are such) even small increases in mortality rates may be significant for the population.


  • The risk of collision is likely to be greater on or near areas regularly used by large numbers of feeding or roosting birds.
  • ·
  • More collision are likely in poor visibility due to fog or rain.
  • ·
  • The precise location of a windfarm is critical because topographic features affect birds flight.  For example, birds are on a lower flight height in some locations i.e. following a coastline which places them at greater risk of collision.


  • Collision rates vary from 0.01 to 23 per turbine (the highest figure being for a Belgian coastal site and relates to gulls, terns and ducks).


  • Some poorly sited windfarms have resulted in sufficient deaths to produce a population level effect.


  • Relatively high collision rates have been recorded at poorly sited wind farms where large concentrations of birds are present


  • The weight of evidence to date indicates that locations of high bird use are not suitable for windfarm development.


Certain species have been identified as being particularly sensitive to windfarm development as a result of displacement, collision or barrier to movement.  The list includes many birds observed at Lendalfoot including gannets, cormorants, herons, swans, geese, ducks, terns, guillemots and owls.


There have been a number of stories reported which would seem to underline the research indicating that turbines do lead to deaths of sea birds:


  • Dorset Echo 3rd July 2010 – Portland school turns off wind turbine to halt slaughter of sea birds.  14 birds were killed in six months by flying into the turbine.


  • North West Evening Mail 20th July 2007 – Tesco turbine in Barrow has proved a pretty efficient bird killer – RSPB say “birds are being killed as a result of installation and Tesco should do more to avoid deaths”.


  • BBC News 24th July 2009 – aquarium in Devon has taken down two wind turbines after seagulls were killed when they collided with the blades.


  • The RSPB objected to a windfarm on north Norfolk coast because the crops encourage the birds to forage would still grow in the area so difficult to prevent them flying/colliding with the turbines.


Gull expert Peter Rock, who has studied gulls for thirty years, acknowledges two types of gull – those that breed on cliffs and follow fishing boats and those which have moved to town and are pests.


Scottish Government Guidance to Accompany the Statutory Nuisance Provision of the Public Health etc (Scotland) Act 2008 clearly acknowledges the nuisance value of birds including gulls as a result of their activity and droppings accumulating.  The guidance acknowledges cases of human disease acquired directly from urban birds including ornithosis, histoplasmosis, salmnellosis, campylobacterosis, mycobcterosis, crytococcosis and toxoplasmosis.


Dumfries and Galloway Council hosted a summit called “Gulls: Friend or Foe” in recognition of urban gulls becoming a serious problem.  The Environment Minister said “seagulls are a real nuisance in Scottish towns and cities, they thrive on litter and are known to remove waste from bins.  Their droppings are obviously a health hazard and they behave aggressively towards other birds, pets and people”.