
WREN has created a free, online tool to catalog monitoring and mitigation technologies developed to assess and reduce potential wildlife impacts resulting from land-based and offshore wind energy development. Technologies are independently reviewed and the tool will be continuously maintained and updated to ensure the international community has access to current, publicly available information on monitoring and mitigation solutions, their state of development, and related research.
Results can be refined by selecting from the drop down menus or entering a search term. You can also download the full list of monitoring and mitigation technologies or look up definition of terms used in this tool.
Technologies are reviewed on an annual basis, but can be updated more frequently if needed, by emailing tethys@pnnl.gov. The wind energy community may also contribute additional technologies for consideration by filling out this survey.
Last updated: 28 July 2026.
Displaying 41 - 80 of 124 technologies
| Type | Stressor & Receptor | Technology | Description | Placement & Integration | Research Summary | Citations |
|---|---|---|---|---|---|---|
| Monitoring, Mitigation Land-based, Offshore Operation |
Turbine Collision Birds |
DTBird DTBird | Camera System , Deterrent The DTBird system aims to automatically detect birds and deter them from flying into the rotor-swept zone of an operational wind turbine. It is comprised of multiple components (high-definition or thermal imaging cameras and speakers), and is mounted on the turbine tower....Read more The DTBird system aims to automatically detect birds and deter them from flying into the rotor-swept zone of an operational wind turbine. It is comprised of multiple components (high-definition or thermal imaging cameras and speakers), and is mounted on the turbine tower. Upon detection, the system emits discouraging sounds and/or stops the turbine. Collisions and potential collisions can be recorded. Species/group identification is done manually. Read less |
Cameras for day and night monitoring can be installed on the tower of the wind turbines or in the transition piece for Offshore projects. When Collision Avoidance module is contracted speakers are placed on the wind turbine tower and/or on the nacelle. Stop Control module is a software configuration which doesn't require additional external hardware. |
Large-Scale Field Study
Nicholls, A.; Barker, M.; Armitage, M.; Votier, S. (2022). Review of seabird monitoring technologies for offshore wind farms. Report by RPS group. Report for Offshore Renewables Joint Industry Programme (ORJIP). ...Read more Nicholls, A.; Barker, M.; Armitage, M.; Votier, S. (2022). Review of seabird monitoring technologies for offshore wind farms. Report by RPS group. Report for Offshore Renewables Joint Industry Programme (ORJIP).
Terrill et al. (2018) used fixed-wing UAVs to evaluate the performance of the DTBird detection and deterrent-triggering systems at the Manzana Wind Power Project located in Kern County, California (US) between December 2016 and August 2017.
Litsgård et al. (2016) monitored bird movement to evaluate the effectiveness of the DTBird system on a wind turbine near Lundsbrunn, Sweden from July to September 2015.
Hanagasioglu et al. (2015) data collected using the DTBird and DTBat systems at the Calandawind wind turbine in Switzerland between June 2014 and October 2014. Data collected were compared to data collected by bird and bat specialists.
May et al. (2012) evaluated the capability of the DTBird system in detecting birds near the rotor swept area of a wind turbine and in studying the flight patterns of birds close to turbines in Norway. Data were collected with the DTBird system between March and September of 2012 at the Smøla wind-power plant in Norway. Read less |
Nicholls et al. 2022, Terrill et al. 2018, Litsgård et al. 2016, Hanagasioglu et al. 2015, May et al. 2012 |
| Monitoring, Mitigation Land-based Operation |
Turbine Collision Birds |
Laufer Wind Eagle Take Minimization System | Radar , Camera System , Software , Multisensor Array The Eagle Take Minimization System aims to detect eagles at risk of flying into the rotor-swept zone of an operational wind turbine at a far enough distance to stop the relevant turbines before collision....Read more The Eagle Take Minimization System aims to detect eagles at risk of flying into the rotor-swept zone of an operational wind turbine at a far enough distance to stop the relevant turbines before collision. The system consists of X-band radar, PZT visible cameras and a Central Controller computer. Read less |
Cameras and radars placed throughout wind farm with overlapping fields of view. |
Laboratory
Petr et al. (2018) discussed the development of the Eagle Take Minimization System. Prototype testing was conducted in Bedford, New Hampshire (US) using drones to simulate golden eagle flight. |
Petr et al. 2018 |
| Monitoring, Mitigation Land-based, Offshore Operation |
Turbine Collision Bats |
Natural Power EchoSense | Acoustic Sensor EchoSense technology aims to use SCADA (supervisory control and data acquisition) data, meteorological data, and acoustic data to curtail wind turbines when bats are present within the swept area of the turbine blades....Read more EchoSense technology aims to use SCADA (supervisory control and data acquisition) data, meteorological data, and acoustic data to curtail wind turbines when bats are present within the swept area of the turbine blades. Additional factors, such as wind speed and minimum temperature, can influence EchoSense automated curtailment decisions established by a predetermined set of rules. EchoSense was formerly known as Detection and Active Response Curtailment (DARC). Read less |
Mounted on the nacelle |
Large-Scale Field Study
Alliant Energy (2024) In 2020 and 2021 from August to October a study was performed at nine wind project sites in Minnesota and Iowa to evaluate the effectiveness of the EchoSense system in reducing bat fatalities in order for future wind farms to receive permits. ...Read more Alliant Energy (2024) In 2020 and 2021 from August to October a study was performed at nine wind project sites in Minnesota and Iowa to evaluate the effectiveness of the EchoSense system in reducing bat fatalities in order for future wind farms to receive permits.
Vallejo et al. (2023) The effectiveness of Echosense was studied at the English Farms Wind Project, located southeast of Montezuma, Iowa between 2020 and 2021. This study tested the system's ability to detect bats and curtail turbine activity accordingly.
Fritchman et al. (2022) EchoSense was used as part of a curtailment research study at the Crescent Wind Project in Hillsdale County, Michigan from May to October of 2021. The study aimed to compare the impact of different curtailment methods, such as blanket curtailment and smart curtailment, on bat mortality. Read less |
Alliant Energy 2024, Vallejo et al. 2023, Fritchman et al. 2022 |
| Monitoring Land-based Planning, Operation |
Attraction, Avoidance, Displacement, Turbine Collision Birds, Bats |
EchoTrack Technology EchoTrack | Radar The EchoTrack Radar–Acoustic Surveillance System is used for observing and conserving airborne wildlife populations. EchoTrack integrates radar and acoustic technologies with a unique algorithm in order to identity animals and isolate flight paths. |
Free standing mobile field labs |
Large-Scale Field Study
Corbeau et al. (2021) assessed the use of EchoTrack for tracking bird activity at Land-based wind farms in France.
Becker et al. (2019) used EchoTrack to observe bird activity at a proposed wind farm on the Cape west coast of South African. ...Read more Corbeau et al. (2021) assessed the use of EchoTrack for tracking bird activity at Land-based wind farms in France.
Becker et al. (2019) used EchoTrack to observe bird activity at a proposed wind farm on the Cape west coast of South African.
Jenkins et al. (2018) utilized EchoTrack radar and software to observe great white pelican activity at a proposed wind facility on the Cape west coast of South Africa. Read less |
Corbeau et al. 2021, Becker et al. 2020, Jenkins et al. 2018 |
| Mitigation Offshore Construction, Operation |
Habitat Change Fish, Ecosystem Processes, Habitat, Invertebrates |
ECOncrete ECOncrete ECO Mats® | Artificial Reef ECO Mats aim to reduce the habitat impacts of underwater cables (like those used in offshore wind operations) by facilitating biogenic buildup on mats of interlocking ECOncrete material covering such cables....Read more ECO Mats aim to reduce the habitat impacts of underwater cables (like those used in offshore wind operations) by facilitating biogenic buildup on mats of interlocking ECOncrete material covering such cables. The concrete mix design consists of ECOncrete® Admix coupled with complex surface textures with the goal of encouraging colonization and attachment by marine epifauna. Read less |
The ECOncrete ACBMs can be used in place of traditional ACBMs, which are typically placed on top of underwater cables or in areas where scour protection is required |
Small-Scale Field Study
Sella et al. (2021) evaluated the structural and biological efficacy of the ECO Mat over two years from April 2017 to April 2019 in Florida (US). ...Read more Sella et al. (2021) evaluated the structural and biological efficacy of the ECO Mat over two years from April 2017 to April 2019 in Florida (US).
Cinti (2021) compared the fish assemblage change associated with the placement of ECO Mat material and control material in Port Everglades, Florida (US). Read less |
Sella et al. 2021, Cinti 2020 |
| Mitigation Offshore Construction, Operation |
Habitat Change Habitat |
ECOncrete ECOncrete Wind Turbine Scour Protection Unit | Artificial Reef ECOncrete® Wind Turbine Scour Protection Units are structural, interlocking, ecological concrete units gravity fed from a barge which intend to replace/complement rock armor scour protection around the base of offshore wind turbines....Read more ECOncrete® Wind Turbine Scour Protection Units are structural, interlocking, ecological concrete units gravity fed from a barge which intend to replace/complement rock armor scour protection around the base of offshore wind turbines. The ecological design of the units and interstitial spaces between them aims to create an environment that mimics optimal marine habitats, while providing the structural functionality required of armoring for scour protection. Read less |
Placed around the base of offshore wind turbines |
Small-Scale Field Study
These units are still in development and will be piloted for Northeast offshore infrastructure in spring 2022. |
No available documents. |
| Monitoring, Mitigation Offshore Planning, Construction, Operation, Decommissioning |
Habitat Change Fish, Habitat, Hydrodynamics, Invertebrates |
The Candide Group Eel Drone | Autonomous Vehicle The eel-like drone is a bio-inspired autonomous underwater vehicle (AUV) engineered for agile, energy-efficient, and low-disturbance operations in complex marine environments....Read more The eel-like drone is a bio-inspired autonomous underwater vehicle (AUV) engineered for agile, energy-efficient, and low-disturbance operations in complex marine environments. Drawing inspiration from natural eel propulsion, it uses undulating motion to maneuver precisely around offshore wind foundations, subsea cables, and sensitive habitats - areas where conventional propeller-driven systems may face maneuverability limits, higher energy demand, or elevated operational costs. The platform is designed with modular integration in mind, enabling deployment of a range of sensors and instruments to support needs throughout the offshore wind project lifecycle. By combining maneuverability, efficiency, and scientific-grade data collection, the eel-like drone enhances safety, adaptability, and cost-effectiveness in offshore wind surveys and monitoring operations. Read less |
Deployed as a mobile platform |
Pilot Field Study
2025–2027 – National Offshore Wind Research & Development Consortium System-level development and validation of a bio-inspired uncrewed underwater vehicle for benthic surveys and offshore wind environmental monitoring. ...Read more2025–2027 – National Offshore Wind Research & Development Consortium System-level development and validation of a bio-inspired uncrewed underwater vehicle for benthic surveys and offshore wind environmental monitoring. 2024 – U.S. Department of Energy SBIR Phase I Laboratory accelerated life testing and early-stage field deployment of water metering systems with energy harvesting capabilities are being conducted to evaluate durability, reliability, and integration under operational conditions. 2023 – U.S. Department of Defense Navy SBIR Extreme shallow-water (<3 ft) pico-marine hydrokinetic (pico-MHK) testing was conducted at forward operating bases to de-risk system performance at higher output levels. 2022 – Los Angeles Cleantech Incubator Stakeholder engagement and private investment activities supported technical validation and commercialization strategy development. While not a laboratory test, this phase advanced system readiness through industry interface and market positioning. 2022 – NOAA Ocean Observation Challenge Wave basin testing was conducted at the U.S. Navy Carderock facility to evaluate ocean instrumentation integration and data collection performance. 2021 – U.S. Department of Energy TEAMER Program Computational fluid dynamics simulations and controlled flume testing at the Stevens Institute were performed to validate an autonomous underwater vehicle concept with integrated energy harvesting capability. 2021 – California Energy Commission Laboratory validation of piezoelectric energy harvesting performance under large cyclic mechanical stresses was conducted to evaluate power generation efficiency and durability. Read less |
No available documents. |
| Mitigation Offshore Construction |
Noise Marine Mammals, Fish, Marine Reptiles |
Electronic and Geophysical Services EGS Bubble Curtain | Noise Reduction The EGS Bubble Curtain aims to reduce the propagation of sound waves during pile driving activities. The bubble curtain consists of a hose with 3 mm holes every 0.3-0.4 m anchored to the sea bottom around the pile-driving operation....Read more The EGS Bubble Curtain aims to reduce the propagation of sound waves during pile driving activities. The bubble curtain consists of a hose with 3 mm holes every 0.3-0.4 m anchored to the sea bottom around the pile-driving operation. Bubbles produced disrupt the propagation of sound from the construction activities. Read less |
Hose anchored to the sea bottom in a circle surrounding the monopile during pile driving |
Large-Scale Field Study
Nehls et al. (2007) compared the costs and efficacy of three methods of noise reduction in pile driving: bubble curtains, modifications to the pile hammer, and pile sleeves. Bubble curtain technologies compared design, diameter, air supply, water depth, and noise reduction....Read more Nehls et al. (2007) compared the costs and efficacy of three methods of noise reduction in pile driving: bubble curtains, modifications to the pile hammer, and pile sleeves. Bubble curtain technologies compared design, diameter, air supply, water depth, and noise reduction. The EGS Bubble Curtain was larger than other bubble curtains, with comparable noise reduction.
Würsig et al. (2000) developed a 25m radius bubble curtain using hose with 3mm holes every 0.3-0.4m through which air was emitted at 20m^3/minute. The sound reduction produced was evaluated for curtain application around a pile driving operation in Hong Kong in April 1996. Noise reductions ranging from 5 to 20 dB were observed, with the greatest reductions in the 1 - 6 kHz frequency range. Read less |
Nehls et al. 2007, Würsig et al. 2000 |
| Monitoring Land-based Operation |
Turbine Collision Birds, Bats |
U.S. Geological Survey and partners Evidence of Absence | Software Evidence of Absence is a software package that is used to address whether the number of fatalities (typically of a rare species or species of concern) at a wind power facility is below a given threshold and what search parameters are needed to give assurance that thresholds were not exceeded. |
Software |
Large-Scale Field Study
Dalthorp and Huso (2015) rigorously tested Evidence of Absence against several hypothetical scenarios. They examined the accuracy and precision of triggers and their sensitivity to input parameters. |
Dalthorp and Huso 2015 |
| Mitigation Offshore Operation |
Habitat Change Fish |
Exo Engineering ExoReef | Artificial Reef ExoReefs are custom-designed artificial reefs created to enhance biodiversity at offshore wind farms. Constructed using sustainable low-carbon concrete alternatives and recycled aggregates, they offer essential habitat for juvenile fish and provide surfaces for reef-building organisms. |
Placed on floor of offshore wind farms |
No available documents. | |
| Mitigation Offshore Construction |
Noise Marine Mammals, Fish, Marine Reptiles |
Menck Fire-Hose System | Noise Reduction The Menck fire-hose system aims to reduce the noise generated by pile driving through use of a two-layer curtain made of inflated, vertically arranged fire-hoses. Sound attenuation occurs due to the physical disruption to sound wave propagation created by the oscillating bubbles. |
Fire-hose system applied around the monopile during construction and removed after pile driving is complete. The system is inflated once applied to the monopile. |
Large-Scale Field Study
Wilke et al. (2012) evaluated various techniques for the reduction of noise in offshore wind turbine pile driving in a field study in Lübeck Bay, Germany. |
Wilke et al. 2012 |
| Monitoring Offshore Planning, Construction |
Attraction, Avoidance, Noise Birds |
Wedge Global FLOating RAdar (FLORA) | Radar , LiDAR , Data acquisition (DAQ) , Acoustic Sensor , Camera System The FLOating Radar (FLORA) is an industrial-scale prototype of a purpose-built, self-powered, oceanic multi-use platform (MUP) with bird detection capabilities....Read more The FLOating Radar (FLORA) is an industrial-scale prototype of a purpose-built, self-powered, oceanic multi-use platform (MUP) with bird detection capabilities. Equipped with a novel sensor suite, FLORA will be deployable as a low environmental impact system for bird and biodiversity data acquisition which is critical to Marine Spatial Planning. Read less |
Free-standing tower with an integrated wave energy converter, wind, and solar to power the device. |
No available documents. | |
| Monitoring Offshore Planning, Construction, Operation, Decommissioning |
Turbine Collision, Attraction, Avoidance Birds, Bats, Marine Mammals, Fish |
Akrocean Fly'rsea | Radar Fly'rsea is a floating RaDAR system powered by clean energy (wave and solar) with 365/7 supervision at an Land-based control center. The system is designed for environmental assessment of a range of species and environmental parameters. |
Independent buoys on offshore wind farms |
Pilot Field Study
Northeastern University (2019) discusses Fly'rsea and the challenges with floating radars for offshore wind farms. |
Northeastern University 2019 |
| Monitoring Land-based Operation |
Turbine Collision Birds, Bats |
U.S. Geological Survey and partners GenEst | Software GenEst is a software package used to estimate the probability of detecting a bird or bat killed at a wind facility, and then to combine the probability of detection with the observed count of carcasses to ultimately estimate total mortality. |
Software |
Large-Scale Field Study
Rabie et al. (2021) compared the performance of GenEst to the Huso and Shoenfeld estimators by simulating mortality and search conditions that might occur in in the field and evaluating each estimator’s ability to accurately estimate a known carcass count. |
Rabie et al. 2021 |
| Monitoring Offshore Construction, Operation |
Turbine Collision Birds |
BioConsult SH HiDef Gen II | Camera System HiDef Gen II is a high-resolution digital video system, specifically designed to detect birds, marine megafauna, and anthropogenic activity offshore. The system uses four high-resolution video cameras, recording at a frame of over eight images per second, across a transect of 500 m width....Read more HiDef Gen II is a high-resolution digital video system, specifically designed to detect birds, marine megafauna, and anthropogenic activity offshore. The system uses four high-resolution video cameras, recording at a frame of over eight images per second, across a transect of 500 m width. The rig conducts surveys with a ground sample distance between 3 cm to 0.5 cm. Read less |
Mounted on a helicopter |
Pilot Field Study
Mellor et al. (2007) trialed the HiDef aerial survey technique for seabirds at windfarm sites....Read more Mellor et al. (2007) trialed the HiDef aerial survey technique for seabirds at windfarm sites. They found the system provides sufficient detail to enable reliable identification of birds in most cases and that operating at altitudes in excess of 1 km are feasible, although cloud-base would be a limiting factor. Despite higher wind speeds than would be tolerated on a conventional survey, all birds were observed on most transects with a high degree of confidence. Read less |
Mellor et al. 2007 |
| Monitoring Offshore Construction, Operation |
Noise Marine Mammals, Fish |
SubSeaSail (SSS) HORUS™ | Autonomous Vehicle HORUS™ is an unmanned autonomous uncrewed surface vessel (USV). HORUS™ vessel (32 kg) is available now for surface monitoring around offshore wind farms. With a monohull design and includes a passive acoustic array. |
Free moving USV |
No available documents. | |
| Mitigation Offshore Construction |
Noise Marine Mammals, Fish, Marine Reptiles |
OffNoise - Solutions Hydro-Sound-Damper System (HSD) | Noise Reduction The Hydro Sound Damper System intends to reduce the noise produced during pile driving in offshore wind turbine installation....Read more The Hydro Sound Damper System intends to reduce the noise produced during pile driving in offshore wind turbine installation. It consists of layers of netting containing air filled envelopes, rubber, and polyethylene foam elements that surround the monopile and physically disrupt sound waves from pile driving. Read less |
Hydro Sound Dampener installed around the monopile during pile driving. Netting is initially fixed to the sea bottom and then stretched to the surface due to buoyancy forces. |
Large-Scale Field Study
Elmer (2018): With a Hydro Sound Damper (HSD) in place, sound was measured at a distance of 6m from the pile, 4m above ground, to record sound levels during pile driving in the German Baltic Sea....Read more Elmer (2018): With a Hydro Sound Damper (HSD) in place, sound was measured at a distance of 6m from the pile, 4m above ground, to record sound levels during pile driving in the German Baltic Sea. Results (a 23dB reduction in noise level) indicated 99.5% of the whole sound energy was damped out by the HSD net.
Elmer et al. (2014) evaluated the noise reduction capacity of the Hydro Sound Dampener during the installation of offshore wind turbines at several locations including the London Array wind farm (Great Britain) and the Amrumbank-West wind farm (Germany) in the North Sea. Read less |
Elmer 2018, Elmer and Savery 2014 |
| Monitoring Land-based, Offshore Operation |
Turbine Collision Birds, Bats |
Norwegian Institute for Nature Research ID-Stat | Acoustic Sensor , Software ID-Stat is a monitoring system which aims to use microphones placed within turbine blades to record bird or bat collisions. The system consists of microphones and software which automatically records detected collisions. |
Microphones installed within turbine blades and accompanying software |
Small-Scale Field Study
Delprat et al. (2011) presented the concept of the ID stat system at the Conference on Wind energy and Wildlife impacts in Norway in May 2011. A small scale study of the technology was scheduled for March 2012 at an Land-based wind turbine. ...Read more Delprat et al. (2011) presented the concept of the ID stat system at the Conference on Wind energy and Wildlife impacts in Norway in May 2011. A small scale study of the technology was scheduled for March 2012 at an Land-based wind turbine.
Delprat & Alcuri (2011) presented at the Conference on Wind Energy and Wildlife Impacts on the 2nd-5th of May 2011, in Trondheim, Norway. Read less |
Collier et al. 2011, Delprat and Alcuri 2011 |
| Monitoring, Mitigation Land-based Operation |
Turbine Collision Birds |
IdentiFlight International IdentiFlight | Software , Camera System , Multisensor Array IdentiFlight aims to combine optical systems with machine vision and AI software to monitor and minimize bird collisions at wind turbines. The IdentiFlight towers operate as an autonomous system with overlapping aerial coverage for detailed viewing....Read more IdentiFlight aims to combine optical systems with machine vision and AI software to monitor and minimize bird collisions at wind turbines. The IdentiFlight towers operate as an autonomous system with overlapping aerial coverage for detailed viewing. Proprietary software and neural network technologies process the images to determine 3D position, velocity, trajectory, and protected species of interest. IdentiFlight has a curtailment module which analyzes birds' flight paths in relation to surrounding wind turbines and determines whether to curtail. Read less |
Autonomous towers in vicinity of wind turbine |
Large-Scale Field Study
Duerr et al. (2023) analyzed the effectiveness of IdentiFlight system's ability to identify different bird species at the Manzana Wind project, in Kern County, California (US) from June 2018 - 2019. ...Read more Duerr et al. (2023) analyzed the effectiveness of IdentiFlight system's ability to identify different bird species at the Manzana Wind project, in Kern County, California (US) from June 2018 - 2019.
Huso & Dalthorp (2023) assessed Identiflight's ability to reduce eagle mortality at Campbell Hill wind farm in Wyoming (US) from August 2018 - 2022.
Rogers (2022) evaluated the efficacy of the Identiflight Avian Detection System at the Castle Hill Wind Farm in Tasmania from August 2020 to February 2022.
McClure et al. (2022) evaluated IdentiFlight's ability to mitigate collision mortality of bald and golden eagles at a wind facility in Wyoming (US).
Rolek et al. (2022) evaluated Identiflight at Top of the World Wind Power Facility in Wyoming (US) from May 2018 to March 2019 and at The Manzana Wind Power Project, in Kern County, California (US) from June 2018 to March 2020.
Aschwanden et al. (2020) monitored bird movements to assess the effectiveness of the IdentiFlight system at the Wind Energy Research Cluster South in Stötten, Germany between April and May 2020.
McClure et al. (2018) used human observation to test and compare the ability of IdentiFlight to detect, classify, and track birds at the Top of the World wind farm in Wyoming (US) from August to September 2016. Read less |
Duerr et al. 2023, Huso and Dalthorp 2023, Rogers 2022, McClure et al. 2022, Rolek et al. 2022, Aschwanden and Liechti 2020, McClure et al. 2018, Reichenbach 2023, Reichenbach et al. 2021 |
| Monitoring Land-based, Offshore Planning, Operation |
Attraction, Avoidance, Displacement, Turbine Collision Bats |
PNNL Injectable RF Bat Tags | Tags The injectible radio-frequency Bat Tags come in three different designs and aim to use a 3D tracking algorithm to track bat movement. The first design is intended for the endangered Myotis species and minimizes transmitter size and weight: 0.16 grams and 10-km detection range....Read more The injectible radio-frequency Bat Tags come in three different designs and aim to use a 3D tracking algorithm to track bat movement. The first design is intended for the endangered Myotis species and minimizes transmitter size and weight: 0.16 grams and 10-km detection range. The second design is intended for hoary, eastern red, and silver-haired bats and prioritizes service life while staying under 5% tag-burden guidelines: 0.4 grams and >20-km detection range. The third design is intended to study potential attraction of bats to wind turbines and fine-scale movements across one or more wind farms and prioritizes detection range while keeping a reasonable size and weight: 0.6 grams and >20-km detection range. Read less |
Transmitters attached to animals, receivers located in the vicinity of the turbine |
Pilot Field Study
Deng et al. (2021) designed a animal tracking transmitter with the goal of reducing weight and increasing transmission range. Drones were used to assess the effective range of the transmitter near Richland, Washington (US) in December 2021. ...Read more Deng et al. (2021) designed a animal tracking transmitter with the goal of reducing weight and increasing transmission range. Drones were used to assess the effective range of the transmitter near Richland, Washington (US) in December 2021.
Deng et al (2019) implemented three designs of animal tracking transmitters aimed at tracking bats for applications in wind energy. Lab scale testing and algorithm validation were undertaken in 2018. Read less |
Lu et al. 2021, Deng et al. 2021 |
| Mitigation Offshore Construction |
Noise Marine Mammals, Fish |
IQIP Integrated Monopile Installer | Noise Reduction The integrated monopile installer is a double-wall steel tube with a protected bubble curtain between the tube and driving pile. The system is placed over the pile and is effective along the entire length of the water column at the pile. Formally known as the Noise Mitigation Screen. |
Wraps around pile during installation |
Large-Scale Field Study
Koschinski & Lüdemann (2020) discuss the first commercial application of the Integrated Monopile Installer in 2012 at the German OWF Riffgat in the North Sea. Since then the Integrated Monopile Installer has been used on over 450 piles....Read more Koschinski & Lüdemann (2020) discuss the first commercial application of the Integrated Monopile Installer in 2012 at the German OWF Riffgat in the North Sea. Since then the Integrated Monopile Installer has been used on over 450 piles. Noise reduction was decreased to a range of 13 to 16 dBSEL.
Rose et al. (2019) analyzed data collected during the construction of Gescha 1 & 2 from 2010 to 2016 to investigate the effects of different types of noise mitigation on harbour porpoises. Read less |
Koschinski and Lüdemann 2020, Rose et al. 2019 |
| Monitoring Offshore Construction, Operation, Decommissioning |
Noise Marine Mammals |
Sea Mammal Research Unit (SMRU) Consulting on behalf of the Scottish Government iPCoD (interim Population Consequences of Disturbance) | Software iPCoD is a modeling approach (R package) for assessing and quantifying the potential consequences for marine mammal populations of any disturbance and/or injury that may result from offshore energy developments....Read more iPCoD is a modeling approach (R package) for assessing and quantifying the potential consequences for marine mammal populations of any disturbance and/or injury that may result from offshore energy developments. It is designed to use the information likely to be provided by developers in their Environmental Statements and Habitats Regulations Assessments. Read less |
Software installed on the developers offsite computer |
Large-Scale Field Study
Booth et al. (2013) illustrate how the iPCoD protocol can be used to consider the potential effects of constructing two hypothetical wind farms off the Aberdeenshire coast on the five priority species over two years in their relevant management units....Read more Booth et al. (2013) illustrate how the iPCoD protocol can be used to consider the potential effects of constructing two hypothetical wind farms off the Aberdeenshire coast on the five priority species over two years in their relevant management units. Additionally, they investigate the cumulative effects of the simultaneous operation of a hypothetical tidal energy installation. Read less |
Booth et al. 2013 |
| Monitoring, Mitigation Land-based, Offshore Planning, Construction, Operation, Decommissioning |
Turbine Collision, Displacement, Habitat Change Bats, Birds, Amphibians, Terrestrial Mammals |
WildLife Acoustics Kaleidoscope Software | Software Kaleidoscope Pro is a sound analysis software that identifies animal vocalizations from recordings. The SMART feature provides a simulation of SMART System alarms based on pre-recorded bat activity....Read more Kaleidoscope Pro is a sound analysis software that identifies animal vocalizations from recordings. The SMART feature provides a simulation of SMART System alarms based on pre-recorded bat activity. The output file indicates timestamps of when any of 16 pass/pulse alarms are activated or cleared. A Bat Auto-ID feature analyzes recordings of bat echolocations and automatically suggests species identifications. Kaleidoscope Pro’s Cluster Analysis uses sophisticated pattern recognition algorithms to automatically scan wildlife audio recordings for vocalizations. The Sound Level Analysis feature analyzes the noise spectrum, including weighted SPL and SEL measurements and third octave band analysis. Read less |
Software operated on computer |
Large-Scale Field Study
McKay et al. (2024) described bat community dynamics at a Norwegian wind farm located in boreal forest. They used Kaleidoscope Pro to process bat acoustic data collected between July - September in 2020. They found evidence to suggest possible direct and indirect effects to bat communities. ...Read moreMcKay et al. (2024) described bat community dynamics at a Norwegian wind farm located in boreal forest. They used Kaleidoscope Pro to process bat acoustic data collected between July - September in 2020. They found evidence to suggest possible direct and indirect effects to bat communities. Peterson et al. (2021) investigated whether acoustic bat data collected at wind farms can provide accurate measures of bat fatality risk. They used Kaleidoscope Pro to analyze bat acoustic data collected at the New Creek wind farm in West Virginia in September 2011 and May 2017. They found that measuring exposure of acoustic bat activity provided a quantitative basis for designing, evaluating, and adaptively managing curtailment strategies.
Richardson et al. (2021) assessed bat activity at paired turbine and control locations at 23 British wind farms. They used Kaleidoscope Pro to process bat calls and classify calls to species level. P. pipistrellus activity was 37% higher at turbines than at control locations, which may explain why Environmental Impact Assessments conducted before the installation of turbines are poor predictors of actual fatality rates. Read less |
McKay et al. 2024, Peterson et al. 2021, Richardson et al. 2021 |
| Monitoring Land-based, Offshore Construction, Operation, Planning |
Turbine Collision, Displacement, Attraction, Avoidance Birds, Bats |
Furuno radars, DHI (software) LAWR (Local Area Weather Radar) | Radar LAWR is a limited range X-Band radar system commonly used for meteorological observations but which has been considered as a system for detecting birds and bats in the proximity of operational wind turbines. |
Radar mounted in proximity of turbines, software to process imagery (BirdTrack, BirdWatch) |
Large-Scale Field Study
Skov et al. (2009) utilized a LAWR system to collect data on the long-distance migration of waterbirds across Horns Rev. The monitoring system was deployed at an offshore wind farm in Denmark from September to November of 2008. |
Skov et al. 2009 |
| Mitigation Offshore Construction, Operation |
Habitat Change Habitat, Fish, Ecosystem Processes |
Reef Ball™ Layer Cake | Artificial Reef Layer Cakes are concrete structures which aim to facilitate reef growth and provide shelter for benthic animals. The structures consist of tiered, cylindrical levels which provide alcoves and increased surface area to facilitate reef establishment. |
Placed around the base of offshore wind turbines, typically in groupings |
Large-Scale Field Study
Hylkema et al. (2023) compared two types of artificial reefs in the Caribbean (2018) by examining fish assemblage, territorial behavior and grazing intensity between reef balls and layered cakes. ...Read more Hylkema et al. (2023) compared two types of artificial reefs in the Caribbean (2018) by examining fish assemblage, territorial behavior and grazing intensity between reef balls and layered cakes.
Hylkema et al. (2020) compared three types of artificial reefs in the Caribbean (2018) by examining the early fish colonization rates between reef balls, layered cakes, and piles of local basaltic rocks. Read less |
Hylkema et al. 2023, Hylkema et al. 2020 |
| Monitoring Land-based, Offshore Planning, Operation |
Turbine Collision Birds, Bats |
Lotek Wireless Lotek Tags | Tags Lotek supplies a variety of avian, terrestrial marine, and freshwater tags. Avian coded VHF tags enable researchers to discover migratory movements of small birds and bats through the Motus network. Tags can be used to establish the presence and absence of individuals at points of interest....Read more Lotek supplies a variety of avian, terrestrial marine, and freshwater tags. Avian coded VHF tags enable researchers to discover migratory movements of small birds and bats through the Motus network. Tags can be used to establish the presence and absence of individuals at points of interest. Some available avian tags include NanoTag Solar, NanoPin, Sunbird Solar Argos Transmitters, and VHF Avian Tags, among others. Read less |
Deployed on animal |
Pilot Field Study
Loring et al. (2021) measured the movements and flight altitudes of 12 species of shorebirds using VHF transmitters, tracked using the Motus Wildlife Tracking System....Read more Loring et al. (2021) measured the movements and flight altitudes of 12 species of shorebirds using VHF transmitters, tracked using the Motus Wildlife Tracking System. The Motus Wildlife Tracking System has extensive coverage from automated radio telemetry stations distributed across Eastern North America and additional coverage at key shorebird sites from Arctic Canada to South America. This study aimed to provide information on offshore movements and flight altitudes of high-priority bird species in order to inform decisions on the development of offshore wind energy facilities in the Atlantic Outer Continental Shelf. Loring et al. (2019) used digital VHF transmitters (NanoTags) to track the offshore movements of three bird species over Federal waters and Wind Energy Areas. Lotek tags were helpful in assessing collision risks in Wind Energy Areas by tracking frequency and extent of offshore movements of these bird species. Read less |
Loring et al. 2021, Loring et al. 2019 |
| Monitoring Land-based, Offshore Operation |
Turbine Collision, Vessel Collision Birds, Bats, Marine Mammals |
Allied Vision Manta | Camera System Manta is a versatile GigE camera series with a modular, flexible design with board level option to facilitate the camera integration in any application. |
Mounted on turbine |
Small-Scale Field Study
Robert et al. (2016) developed and experimentally tested an array of sensors that continuously monitors for interactions of birds and bats with wind turbines, including Allied Vision's Manta camera....Read more Robert et al. (2016) developed and experimentally tested an array of sensors that continuously monitors for interactions of birds and bats with wind turbines, including Allied Vision's Manta camera. They tested the Manta 201 - C and found the stereo visual Manta cameras had a resolution of 1624 x 1234 and sampled at 6 fps with a 52° field of view lens. Read less |
Suryan et al. 2016 |
| Monitoring Offshore Operation |
Habitat Change Invertebrates |
Bluestream Offshore and Wageningen Marine Research Marine Growth Sampling Tool | Biological Sampler The Marine Growth Sampling Tool (MGST) was developed to investigate underwater fauna on wind turbine foundations, addressing the high safety standards and costs associated with diving operations....Read more The Marine Growth Sampling Tool (MGST) was developed to investigate underwater fauna on wind turbine foundations, addressing the high safety standards and costs associated with diving operations. It can be attached to a Remotely Operated Vehicle (ROV) to scrape marine life from turbine foundations. This tool samples biological growth on offshore wind turbine foundations without damaging the foundation coating. Read less |
Mounted on ROV |
Pilot Field Study
Coolen et al. (2025) evaluated the MGST at the Hollandse Kust Zuid offshore wind farm in 2023. The tool successfully collected 21 biofouling samples with high precision at depths of 4.5–20 m....Read more Coolen et al. (2025) evaluated the MGST at the Hollandse Kust Zuid offshore wind farm in 2023. The tool successfully collected 21 biofouling samples with high precision at depths of 4.5–20 m. The three scraper types tested (one metal, two plastic) showed no significant differences in sample quality, species richness, or abundance of scraped biofouling. All scraper types caused negligible damage to turbine coatings. Read less |
Coolen et al. 2025 |
| Monitoring, Mitigation Offshore Construction, Operation |
Vessel Collision Marine Mammals |
Toyon Marine Observer – Maritime Infrared Camera System with AI | Camera System Marine Observer is a maritime infrared camera and proprietary detection software system that reduces the risk of vessel strikes on whales, marine mammals and other objects and automatically detect marine mammals, vessels or other targets....Read more Marine Observer is a maritime infrared camera and proprietary detection software system that reduces the risk of vessel strikes on whales, marine mammals and other objects and automatically detect marine mammals, vessels or other targets. This weatherproof camera module consists of multiple uncooled long-wave infrared camera cores, each with a resolution of 640x512 pixels at 30fps with 90FOV. Read less |
Mounted on a vessel or land-based platform |
Small-Scale Field Study
Guazzo et al. (2019) explored the use of Toyon Research Corporation's detection system to observe North Pacific gray whales....Read more Guazzo et al. (2019) explored the use of Toyon Research Corporation's detection system to observe North Pacific gray whales. They used a combination of visual sightings, acoustic calls, and infrared camera data on blow detections to calculate the cue rates of migrating eastern North Pacific gray whales in January 2015 Read less |
Guazzo et al. 2019 |
| Monitoring Land-based, Offshore Operation, Planning |
Turbine Collision Birds, Bats |
DeTect Merlin Avian Radar System | Radar The MERLIN Avian Radar System is designed to use horizontal and vertical radar to determine the flight path of birds and bats with the intent of capturing flight data. The radar system can be adjusted to remain within a user-assigned perimeter....Read more The MERLIN Avian Radar System is designed to use horizontal and vertical radar to determine the flight path of birds and bats with the intent of capturing flight data. The radar system can be adjusted to remain within a user-assigned perimeter. The system consists of radar hardware and bird tracking software for automatic registration of bird echos and for data collection during day and night. Read less |
Radar system located in the vicinity of the turbine or mounted vertically on tower |
Large-Scale Field Study
May et al. (2017) evaluated the detection ranges of the MERLIN Avian Radar by using an unmanned aerial vehicle to simulate various flight patterns and bird sizes. The study took place off the coast of Central Norway in August 2009. ...Read more May et al. (2017) evaluated the detection ranges of the MERLIN Avian Radar by using an unmanned aerial vehicle to simulate various flight patterns and bird sizes. The study took place off the coast of Central Norway in August 2009.
Skov et al. (2016) utilized the MERLIN Avian Radar in a study of soaring migrants and their attraction to an offshore wind farm in Denmark during the autumn raptor migration in 2010 and 2011.
Fijn et al. (2015) implemented the MERLIN Avian Radar system at the Dutch offshore wind farm Egmond aan Zee from June 2007 to May 2010 in order to study bird flight intensity in the rotor swept zone (25m-115m) over the North Sea. The Merlin system was used to observe fluxes as well as flight altitudes and paths.
Krijgsveld et al. (2011) studied the collision risks and barrier effects of birds due to the Offshore Wind farm Egmond aan Zee in the Netherlands using the MERLIN Avian Radar System between April 2007 and June 2010. Read less |
Fijn et al. 2015, May et al. 2017, Skov et al. 2016, Krijgsveld et al. 2011 |
| Monitoring Land-based, Offshore Operation, Planning |
Turbine Collision, Displacement Birds |
DHI Group MUSE: Multi-Sensor bird detection | Multisensor Array , Radar , Camera System The Multi-Sensor bird detection system MUSE uses a combination of horizontal radar with infrared and visual cameras in order to detect and record flying birds in the proximity of a wind turbine....Read more The Multi-Sensor bird detection system MUSE uses a combination of horizontal radar with infrared and visual cameras in order to detect and record flying birds in the proximity of a wind turbine. The system is used by an offshore wind farms in the Netherlands, United Kingdom and United States to monitor bird interactions with wind turbines. Read less |
Horizontal radar and cameras located in the vicinity of wind turbines |
Small-Scale Field Study
Lagerveld et al. (2020) evaluated various technologies developed to detect bird and bat collisions with wind turbines. |
Lagerveld et al. 2020 |
| Monitoring, Mitigation Offshore Planning, Construction, Operation, Decommissioning |
Attraction, Avoidance, Lighting, Noise, Turbine Collision, Vessel Collision, Vibration Bats, Birds, Fish, Habitat, Marine Mammals, Marine Reptiles |
Mysticetus Mysticetus | Software Mysticetus is a comprehensive software suite designed to optimize real-time monitoring, mitigation, and analysis for protecting marine environments during offshore operations....Read more Mysticetus is a comprehensive software suite designed to optimize real-time monitoring, mitigation, and analysis for protecting marine environments during offshore operations. Mysticetus seamlessly integrates data from diverse sources—including human observers, infrared cameras, electronic monitoring equipment, and external databases—providing a centralized platform for informed decision-making. Mysticetus offers an Automated Data Integrity Service, which includes streamlined workflows for data quality control, automated verification processes, and simplified reporting procedures, ensuring both data integrity and regulatory compliance. Furthermore, Mysticetus enables sophisticated spatial-temporal analysis to identify trends, patterns, and potential risks to marine life. Importantly, data captured in Mysticetus is easily leveraged for future permitting needs. Mysticetus OnCloud's powerful query engine streamlines the process for subsequent projects, making it a valuable tool for long-term environmental stewardship. Mysticetus is effectively mitigating environmental impacts in offshore wind energy, oil & gas exploration, and marine construction projects. Read less |
On vessel, platform, or ROV/surface vehicle. |
Large-Scale Field Study
Smith et al. (2020) conducted a field comparison of real-time detections made by marine mammal observers using Mysticetus, a rotating infrared camera, and via passive acoustic monitoring offshore Atlantic Canada. |
Smith et al. 2020 |
| Monitoring Offshore Planning, Construction, Operation, Decommissioning |
Noise Marine Mammals |
Mseis Night Hawk III | Acoustic Sensor The Night Hawk series is a product line of passive acoustic monitoring sensors that can detect ultrasonic vocalizations up to 180KHz. |
Can be configured for short or long length towed arrays |
Small-Scale Field Study
Moron et al. (2018) recorded Clymene dolphin whistles in the Southwest Atlantic Ocean in 2016 using a Night Hawk III four-element towed array. ...Read moreMoron et al. (2018) recorded Clymene dolphin whistles in the Southwest Atlantic Ocean in 2016 using a Night Hawk III four-element towed array. Verfuss et al. (2017) compared and discussed a variety of methods suitable for monitoring marine mammals in low visibility conditions during seismic surveys, including the Night Hawk system. Read less |
Verfuss et al. 2018, Klinck et al. 2021 |
| Mitigation, Monitoring Offshore Construction, Operation |
Vessel Collision Marine Mammals |
Current Scientific Corporation Night Navigator | Camera System There are multiple Night Navigator camera systems, the exact specifications of which vary depending on the system. Multiple sensor configurations are available in both uncooled and cooled thermal imaging, offering a broad range of fields of view or levels of optical zoom....Read more There are multiple Night Navigator camera systems, the exact specifications of which vary depending on the system. Multiple sensor configurations are available in both uncooled and cooled thermal imaging, offering a broad range of fields of view or levels of optical zoom. Each payload is gyro-stabilized with the ability to continuously pan through a full 360°, meaning that a target being tracked can be kept in view without interruption. Read less |
Mounted to ship |
Small-Scale Field Study
Smultea et al. (2020) used a variety of monitoring technologies to observe protected species as part of a vessel survey of the Revolution Wind Lease Area in September 2019 - 2020. Night Navigator was used in tandem with 7 other monitoring technologies. |
Smultea et al. 2020 |
| Mitigation Land-based Planning, Operation |
Turbine Collision Birds |
National Laboratory of the Rockies (NLR) NLR-Stochastic Soaring Raptor Simulator | Software SSRS (Stochastic Soaring Raptor Simulator) is a generalizable, probabilistic, predictive model that estimates the potential for collisions between soaring raptors (particularly golden eagles, which rely heavily on updrafts to subsidize flight) to interact with operating wind turbines, without the...Read more SSRS (Stochastic Soaring Raptor Simulator) is a generalizable, probabilistic, predictive model that estimates the potential for collisions between soaring raptors (particularly golden eagles, which rely heavily on updrafts to subsidize flight) to interact with operating wind turbines, without the need for site-specific data collection. The model uses publicly available wind condition data and ground surface information, combined with energy-minimization principles to simulate thousands of eagles at turbine-scale resolution (50 m) and generate a soaring raptor density map. Model outputs may be used to inform pre-construction studies and siting decisions. Read less |
Open source modeling tool |
Laboratory
Sandhu et al. (2022) simulated golden eagle flight paths using an updraft field. Model results were validated with golden eagle telemetry data from a study location containing three wind power plants in Casper, Wyoming (US) for years 2019 and 2020. |
Sandhu et al. 2022 |
| Monitoring Land-based Operation |
Turbine Collision Bats, Birds, Invertebrates |
National Laboratory of the Rockies (NLR) NLR-Thermal Video Processing Software (WEBAT) | Camera System The WEBAT (Wind Energy with Bat AI-based Tracker) is a Python-based bat tracking software, integrating machine learning and computer vision with infrared thermal sensors to enhance the monitoring and protection of bats in proximity to wind turbines....Read more The WEBAT (Wind Energy with Bat AI-based Tracker) is a Python-based bat tracking software, integrating machine learning and computer vision with infrared thermal sensors to enhance the monitoring and protection of bats in proximity to wind turbines. This software supports extracting 2D (pixelwise coordinates) and 3D (real-world coordinates) flight trajectories of bat, bird, and insects. Read less |
Sensors installed near base of turbine tower, pointing up toward blade |
Pilot Field Study
Ryu et al. (2024) tested the system on a dataset of over 800,000 images of bats, birds, insects, and non-biological objects. The system identified bats at a success rate of 93%, birds at a success rate of 94%, insects at a success rate of 83%, and non-biological objects at a success rate of 99%....Read more Ryu et al. (2024) tested the system on a dataset of over 800,000 images of bats, birds, insects, and non-biological objects. The system identified bats at a success rate of 93%, birds at a success rate of 94%, insects at a success rate of 83%, and non-biological objects at a success rate of 99%. Read less |
Ryu et al. 2024 |
| Mitigation Offshore Construction |
Noise Marine Mammals, Fish, Marine Reptiles |
AdBm Technologies Noise Mitigation System | The AdBm Noise Mitigation System aims to reduce the noise produced by pile driving during offshore wind turbine installation. The system consists of Hemholtz resonators contained in a slatted system which unfolds around the monopile during deployment. |
Noise Mitigation System surrounds the monopile during pile driving. The system is unfolded in a similar fashion to venetian blinds |
Large-Scale Field Study
Elzinga et al. (2019) tested the Noise Mitigation System at the Butendiek and Luchterduinen Offshore Wind Parks in the Netherlands in the fall of 2018. ...Read more Elzinga et al. (2019) tested the Noise Mitigation System at the Butendiek and Luchterduinen Offshore Wind Parks in the Netherlands in the fall of 2018.
Wochner (2019) discussed the three approaches to reducing noise from pile driving: reducing at the source, breaking the transmissions path, and noise absorption. Read less |
Elzinga et al. 2019, Wochner 2019 |
| Monitoring, Mitigation Land-based, Offshore Operation |
Turbine Collision Birds, Bats |
nvisionist nvbird | Multisensor Array , Deterrent , Camera System nvbird aims to use a machine learning algorithm in collaboration with HD cameras to recognize the protected birds, analyze their flight path, and deter them with special sounds. If the incoming bird is not deterred the system is intended to stop the wind generator until the birds fly away. |
Even with blade tips on the tower |
No available documents. | |
| Mitigation Offshore Operation |
Habitat Change Invertebrates |
Van Oord - Marine Ingenuity Oyster tables | Artificial Reef Oyster tables are artificial reef structures or platforms designed to support the growth and restoration of oyster populations. These structures can be deployed around offshore wind farms to enhance marine biodiversity, improve water quality, and provide habitat for various marine species. |
Materials are deployed on the seafloor around wind turbine foundations |
Pilot Field Study
Didderen et al. (202) describe a pilot restoration project using oyster tables at the offshore Windpark Eneco Luchterduinen in the Netherlands in 2022. They looked at environmental consequences, lessons learned, and applicability for scalability of the technique. |
Didderen et al. 2019 |
| Monitoring Offshore Construction, Operation, Planning |
Noise, Avoidance, Cumulative Effects, Displacement Marine Mammals |
MTC Media PAMGuard | Software Freely available, open source PAMGuard software is designed to aid in the analysis of passive acoustic monitoring data. The software aims to detect, locate, and classify marine mammals from the sounds they produce. |
PAMGuard analyzes passive acoustic monitoring data |
Large-Scale Field Study
Clausen et al. (2019) examined the performance of different passive acoustic monitoring filters and detectors in varying ocean noise environments....Read more Clausen et al. (2019) examined the performance of different passive acoustic monitoring filters and detectors in varying ocean noise environments. The PAMGuard system was used to analyse harbour porpoise clicks and ambient noise data collected in the spring of 2013 and summer of 2014 in the west of Denmark.
Sarnocinska et al. (2017) observed harbor porpoises in the Danish Great and Little Belts between June and November, 2015 with C-PODS and PAMGuard. The accuracy of both methods was compared.
Keating et al. (2013) describe the beaked whale detectors and classifiers used during beaked whale surveys in Southern California (US) in the summer and fall of 2012.
Yack et al. (2009) evaluated the efficacy of using PAMGuard software (version 1.0) to detect cetaceans in marine environments by comparing manual detections to those made by PAMGuard during a SWFSC dolphin survey conducted in the eastern tropical Pacific Ocean from 20 August to 28 November, 2007. Read less |
Clausen et al. 2019, Sarnocinska et al. 2016, Keating and Barlow 2013, Yack et al. 2009 |