Using drones for ecology: moving towards best-practice guidance

Using drones for ecology: moving towards best-practice guidance

In the third of a series of articles that looks at the use of Unmanned Aerial Vehicles (UAVs) or drones for ecological survey, BSG Ecology Partner Steve Betts discusses guidelines for ecologists to ensure that this technology is used appropriately. BSG Ecology is now using drones to assist with site assessments, as they allow easy monitoring of areas that are otherwise difficult to access.


The use of drones is regulated by the Civil Aviation Authority (CAA) who issue a Permit to Work for their commercial use.  In order to obtain a Permit to Work it is necessary to provide the CAA with proof of the pilot’s overall airmanship skills and awareness, as well as their ability to operate the aircraft safely.  Whilst pilot competence is appraised as part of the CAA’s regulatory procedures, there is currently no ‘best practice’ guidance available on the use of drones for ecological surveys and monitoring.

Project Design

Whilst drones provide a non-intrusive method of collecting data on vegetation, the survey and monitoring of animals is potentially problematic.  Drones can result in the disturbance of some species, such as birds, with engine noise and the visual impact of the drone potentially resulting in an increase in bird alertness, changes in behaviour or even flight initiation.  It is therefore important that these effects are recognised when ecological applications are being considered.

When designing a drone survey, it is important to consider what the survey objectives are and whether they are achievable given the limitations of the equipment.  Central to this is understanding the resolution limitations of the camera, and hence what height flights are required to achieve the required resolution.  It follows that if low level flights are required, the potential for disturbance of terrestrial animals may require careful consideration.

Landowner Permission

Obtaining landowner permission is an important consideration, particularly when the purpose of a flight is to gather data for commercial purposes.  Guidance published by the CAA¹ advises that permission to conduct aerial work will include various operational limitations including one that will normally prohibit flights unless permission has been obtained from the landowner on whose land the drone is intended to take off and land.

Drone ImageSection 76(1) of the Civil Aviation Act 1982 indicates that over-flying third party land does not in itself constitute an offence, as long as it is at a height above the ground which is reasonable.  Nevertheless, as the purpose of any such flight is likely to be some sort of ecological surveillance it is recommended that ‘aerial trespass’ is avoided to prevent future issues arising with regard to data use.

European Sites

Whilst in most cases there is no specific legislation that prohibits the flying of drones over European sites (Special Areas of Conservation (SACs), Special Protection Areas (SPAs) and Ramsar sites), these sites may be subject to site-specific byelaw protection.  This can include the prohibition of activities that are likely to disturb the species that the site in question is noted for, for example birds in SPAs.  It is therefore important that no flights are carried out over or near European sites without first gaining a full understanding of the species that are present and evaluating the likely impacts on those species.

A precautionary approach should always be adopted whereby if it is not known if an effect will occur then the flight should not take place or it should be modified such that there is confidence that an unacceptable effect will not occur.  Natural England, Natural Resources Wales or Scottish Natural Heritage should always be consulted in situations where a European site is the location being surveyed and to consider on a case by case basis whether the flying of drones within a European site requires a Habitats Regulations Assessment under the provisions of the Conservation of Habitats and Species Regulations 2010 (as amended).

Best Practice

In the absence of ecological best practice guidance or national standards, BSG Ecology has prepared the following guidance for use by its own drone pilot.  It is published here to stimulate discussion with regards to the adoption of appropriate standards within the industry:


  • Pilots should only use drones if they have received the appropriate training and secured a Civil Aviation Authority (CAA) ‘Permit to Work’.
  • In most situations a pilot should not work alone as an observer will be needed for health and safety grounds.
  • If assistants are used they should receive the necessary training beforehand, which will include communication procedures and an emergency response strategy.
  • Drones should be operated in accordance with a Flight Manual specific to the aircraft being used.
  • All flight details should be recorded after a flight has been completed, so that a detailed log is developed of all flight activity (this is a requirement of the CAA Permit to Work).

Drone image of St Mary's HospitalPermission

  • Drones should only be used within the constraints imposed by the Permit to Work, which typically allows drones to be operated under Visual Line Of Site (VLOS) rules (i.e. they can be flown to a maximum height of 400 feet and a maximum horizontal distance of 500m from the operator).
  • Land owner permission must be obtained for the take-off and landing site that is being used.
  • Land owner permission should be obtained for any land in third party ownership that it is intended to cover during the flight.


  • Drones should not be used for monitoring wildlife unless there is sufficient weight of evidence to indicate that significant disturbance is not likely to occur.
  • If a drone is used to monitor wildlife an observer should be used to monitor the behaviour of the target species. If an unacceptable level of disturbance is observed then the flight should be aborted.
  • Drones should not be used to monitor bird nesting sites.
  • If the drone is attacked by a bird then the flight should be aborted.
  • Avoid flying near livestock, particularly horses and cattle, as a drone could cause the animals to panic. If this is necessary then always seek advice from the owners of the livestock.
  • When the primary objective of a flight is to gather habitat data, it is important to be aware of the possible presence of sensitive species, such as birds.


Drones provide a useful tool to help ecologists with site assessments, particularly where access is challenging or where it is advantageous to cover sites quickly.  Notwithstanding this, the commercial use of drones is necessarily subject to a rigorous regulatory framework, which is necessary to minimise the risk to the public and others.  In the absence of industry guidance on the use of drones by ecologists, BSG Ecology is proposing a framework based approach for drone use which minimises impacts on ecology.  By adopting best practice procedures we can ensure that an efficient, consistent and rigorous approach is used to benefit clients.

The purpose of sharing this information is to stimulate discussion within the industry, with the objective of improving the use of this technology for clients.  To discuss the use of drones technology and the emerging BSG guidance or for advice on how drones can help with your project please contact Steven Betts, Partner – 0191 3038964


¹ CAA (2015). Unmanned Aircraft System Operations in UK Airspace – Guidance: CAP 722

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