Airport Wildlife Management Bulletin - TP 8240 - No. 36

Bulletin No. 36 - Winter 2006

Avian Radar


As aviation-industry and public awareness grow regarding airport wildlife management, so too has the range of tools and technology available for mitigating wildlife hazards. One technology that has been gaining credibility in recent years is avian radar, which is designed to locate, identify and track birds in airport environments.

Research and development in this field has been ongoing for many years. One of its early proponents was bird biologist Dr. Hans Blokpoel. In his 1976 publication, Bird Hazards to Aircraft, Blokpoel speculated that the probability and severity of collisions between birds and aircraft could be calculated if a radar system could deliver accurate information on the distribution, quantity and location of birds in the air.

Blokpoel identified five areas in which technological advancements could help radar achieve such capability:

Radar characteristics

This refers to the technology’s performance, or the maximum range at which a specific target can be detected. Performance depends on peak power transmitted in relation to receiver sensitivity, as well as radar resolution, or the ability to distinguish individual targets that are close together. Each radar pulse is made up of resolution cells. Within each cell there could be an indeterminate number of birds; therefore, the smaller the cell (or the higher the radar resolution), the greater the capacity to accurately identify the number of birds.


In the late 1970s, radar relied on PPI (Plan Position Indicator) screens to display visual information. This technology posed a number of challenges, including its limited range of brightness levels, which made it difficult to distinguish the number or type of birds.

Radar fixes

Specific technological factors, such as radar fixes (electronic techniques to improve the detection ability of existing radar), improved radar’s ability to fulfill its intended purpose, but hampered the effectiveness of bird detection. These capabilities included moving target indicators (to eliminate stationary targets), sensitivity time control (to eliminate undesired small echoes), and circular polarization (to suppress echoes from precipitation and humidity).

Height distribution

Both the volume of a resolution cell and the curvature of the earth meant that the heights of birds could not be determined reliably with typical surveillance radar.

Record keeping and information utilization

Counting bird echoes on live PPI screens is virtually impossible. Blokpoel recognized a need for a system that would enable storage and retrieval of radar imagery, providing a permanent record for later analysis and trend identification.

In short, 1970’s-era surveillance radar lacked the sophistication that would clearly be required in an effective bird-tracking system. To be fair, however, the technology had not been intended for use on wildlife, let alone objects as small and unpredictable as birds. Blokpoel realized that customized bird, or avian, radars would have to be developed to provide legible bird information-information that could then be translated into useful data and meaningful strike-risk information for ATC operations.

North American Bird Strike Advisory System Strategic Plan

Bird radar is just one of the technologies that will benefit under this strategic plan, which is a development effort led by the Institute for Information and Technology Applications (IITA) at the U.S. Air Force Academy. The first step toward consolidating and integrating various United States and Canadian civil and military efforts to develop and implement a North American Bird Strike Advisory System, the plan is championed by the US Air force, Federal Aviation Administration and Transport Canada.

The purpose of the strategic plan is to cooperatively research, develop and implement advisory systems-such as avian radar-that would produce real-time, widely available and efficiently accessible data to greatly reduce risks to aircraft, aircrew and passengers. By fully integrating all disparate systems and efforts currently under deployment, development and proposal, cooperation between government and other agencies can help ensure an integrated, compatible, coordinated North American Bird Strike Advisory System for the benefit of all aviation operations.

Current state of the technology

The primary purpose of this bulletin is to provide an update on (compiled by Kory Litt at Transport Canada) from industry bird-detection radar vendors and researchers. Please note that the claims and capabilities outlined in this bulletin are those of individual companies, organizations and experts, and have not been verified by Transport Canada. Additionally, the inclusion of these submissions does not constitute endorsement by Transport Canada of any product, technology or company.

More information on liability associated with airport wildlife management can be accessed through:

the Transport Canada publication Sharing The Skies (TP13549E)

Demonstrated Successes and Emerging Technologies

1. Avian Hazard Advisory System (AHAS)

AHAS was developed by the United States Air Force to provide information on real-time bird concentrations and behaviors in U.S. military training routes, military operating areas, bombing ranges, and airfields. Operational since 1998, the system updates bird-strike risk levels every 20-35 minutes and displays trend data that anticipates bird activity into the next hour.

A key signifi cance of AHAS may be the synergy it achieves by incorporating a range of elements, namely:

  • data on bird activity gathered by next-generation weather radar (NEXRAD),
  • strike rates for specific bird species, and
  • US Air Force Bird Avoidance Model (BAM) information.

BAM was created by the USAF in the early 1980s to help warn flight crews of bird activity. BAM uses geographic information system (GIS) technology to analyze and correlate information on bird habitats, migration, and breeding characteristics, combined with key environmental and man-made geospatial data. In effect, the system assigns each square kilometre of the U.S. a unique bird-strike risk value, and allows users to obtain bird hazard information according to location, time of year, time of day, and planned flight route.

More information on AHAS:

2. Sicom Systems Ltd.

ACCIPITER® Avian Radar

Sicom began developing Accipiter in 1994 to provide local, real-time and historical situational awareness of bird and aircraft movements for applications in civil aviation, wildlife management, and environmental assessment. Operational deployments have been undertaken by the U.S. Navy (since 2004), the United States Department of Agriculture Wildlife Services (2005),) in cooperation with the U.S. Marine Corps, and in recent tests during November 2005 at Toronto Pearson International Airport. Variants of Accipiter have also been deployed in operations involving the RCMP, DND, the New York State Police, and the U.S. Department of Homeland Security.

Accipiter’s standard features usually include:

  • MHT/IMM tracking for small targets.
  • Fully integrated, geographical information system (GIS) that provides coordinates, speed, heading, and size parameters for up to 1,000 targets updated every 2.5 seconds.
  • Continuous, 24/7 recording of GIS target data for measuring effectiveness of habitat-management and riskmitigation strategies through off -line analyses. This recording capability
  • Unlimited recording capacity.
  • High-speed playback to visually review nighttime bird activity.
  • Statistical and historical overlays to interpret correlation between bird behavior and underlying geography, and to compute and display bird counts and bird fluctuation over particular observation intervals.


Other features include:

  • An SQL Radar Data Server (RDS) that organizes target data from multiple Accipiter radars in real-time. The RDS responds to user definable queries from multiple users and supports web services for real-time information retrieval, multi-sensor fusion, historical/statistical assessments, and automated bird advisories.
  • Network capability to distribute target data in real-time to remote users on LANs, WANs, or public networks (such as the Internet).
  • Remote control of radar hardware and software to reduce operational and lifecycle costs and provide completely unattended operation.
  • Automated alerts distributed via e-mail and/or cell phone text messaging.

For more information on Accipiter:

  • proceedings of the 2005 IEEE international radar conference and the 2005 bird strike canada conference contain information on successful bird-tracking results in dense, nighttime, fall and spring migration at the patuxent river naval air station using the navy’s eBIRDRAD confi guration (with accipiter):
  • Dr. Tim J. Nohara
    Sicom Systems Ltd
    P.O. Box 366
    Fonthill ON
    Canada L0S 1E0
    Tel: (905) 892-1875

3. Geo-Marine Inc. (GMI)

Mobile Avian Radar System™ (MARS™)

GMI’s MARS uses commercial marine-band radars and proprietary software to:

  • remove background clutter;
  • determine, track and classify targets; and
  • automatically archive target information to a database.

The system runs 24/7, continuously recording data.

MARS features two central components: TracScan S-band (10 cm wavelength) and VerCat X-band (3 cm wavelength) radars. These units are available either individually or in a combined system.

TracScan provides horizontal surveillance of avian migratory ground track, and is capable of detecting flocks of small birds at a range of 4 nm and single birds at ranges between 1 and 2 nm (detection ranges quoted for both systems are longer for larger birds such as waterfowl). The unit has an altitude beam width of 25 degrees-12.5 degrees above and 12.5 degrees below horizontal.

Able to detect flocks of birds at an altitude of 8,000 ft, VerCat provides altitude surveillance along a bearing axis. The unit has a horizontal beam width of 20 degrees-10 degrees to either side of the scan axis. At a range of 5,000 ft, VerCat sees targets 800 ft to either side of its scan axis.

GMI’s proprietary software correlates bird targets into tracks for both TracScan and VerCat. Data associated with a target track include size, speed, heading and position relative to the radar. A tracked target is counted once in data analyses regardless of track length; this results in more accurate target counts. Tracked datasets can be analyzed for spatial distribution by altitude and by heading, comparing avian activity before, during and after migratory periods.

Bird Detection System (BDS), Europe

GMI’s BDS is a radar-based system designed to detect the location and flight direction of flocks of Greylag Geese and Tundra Swans within 3 nm of a Royal Air Force (RAF) air- field, and display their position with reference to aircraft in the traffic pattern


The BDS is comprised of both TracScan and VerCat radars. Detections by both radars are displayed simultaneously in the control room for real-time use by RAF air traffic controllers. The controllers use this information to advise aircrews of the presence and locations of birds, day or night, and in inclement weather. The system operates 24/7 with less than 2% downtime. Accuracy of detections is verified annually under a formal ground-truthing protocol executed at the beginning of each wintering activity season.

For more information:

Tel: (972) 423-5480

4. DeTect Inc.

MERLIN ™ Bird Strike Avoidance Radar System

DeTect develops and commercializes radar-based bird detection technologies for both military and civil bird-aircraft strike-hazard management. A contributor to the creation of AHAS (see above), DeTect also manufactures and supports the MERLIN aircraft bird strike avoidance radar system: a production-model, real-time mobile radar designed for close-in airfield detection of hazardous bird activity.

DeTect’s MERLIN system entered the market in 2003, and is currently available in three standard models.

MERLIN uses a dual marine-radar configuration to provide 2.5-dimensional (2.5-D) bird-detection capability with ranges up six nm (nautical miles) around an airport and altitudes up to 15,000 ft AGL (above ground level). The system incorporates DeTect’s proprietary radar data-processing, clutter mapping, data recording (raw and processed radar data), display, distribution and analysis software suite that was developed specifically to detect and track the unique behavioral characteristics of birds.


MERLIN enables ATC, airport operations and bird-control units to monitor high-risk zones (e.g., runway ends, corridors) even during inclement weather. The system can be controlled-and data can be viewed remotely-through an Internet interface. Audible and/or visual alerts via workstation, pager or cell-phone alerts can be delivered when elevated risk is detected. MERLIN also records bird-track data attributes-including bird size (small, medium, large, fl ock), speed, bearing and altitude-to a GIS-exportable database that can be used in long-term resource management and planning

DeTect will have 12 MERLIN systems in operation in the U.S. and Europe by early 2006. The company also plans to introduce a fourth MERLIN production model for forward-base military deployment in conflict zones. Long-term development 3-D bird detection radar system.

Additional two- to three-month trials of MERLIN are currently scheduled to begin at Dallas-Fort Worth International Airport in early 2006, and at Calgary International by June.


In 2005, and in cooperation with a major North American airport, DeTect prototyped RAPTOR RADAR: an Internetbased, large-scale bird advisory system for commercial aviation. RAPTOR is based on the U.S. NEXRAD radar network and is intended to:

  • provide near real-time bird-density levels in colour-coded image formats within 10-50 nm range views;
  • provide specific airport and area bird-density imagery to subscriber airports through the Internet with onekilometer resolution; and
  • allow bird control units and ATC to view regional and local bird-activity imagery and subsequently direct aircraft approaches and departure traffic around high activity areas.

For more information:

5. FAA Technical Center

Research and development on bird detection radar

In 2002 the FAA joined with the U.S. Air Force Research Laboratory to solicit bids under the Dual Use Science and Technology (DUST) program for development of airport bird detection radar. The successful bidder, WaveBand Corporation of Irvine, California, designed and constructed BIRDAR™-a millimeter-wave (MMW), 94 GHz frequency-modulated, continuous wave (FMCW) detection system.

BIRDAR’s specifications include:

  • a three-mile detection range,
  • altitude determination up to 3,000 ft.,
  • lack of interference with existing airport equipment or operations, and
  • capacity for integration into existing airport GIS systems.


BIRDAR’s scanning antenna achieves 0.5-degree resolution in one dimension and either 2.5 or five degrees in the orthogonal direction. The 0.5-degree beam can be electronically scanned from 30 to 360 degrees, while the five-degree beam can be scanned using a stepper motor. The antenna can be rotated by 90 degrees so that the narrow beam scans horizontally or vertically, depending on desired use.

Supported by CEAT (Centre for Excellence in Airport Technology), BIRDAR’s demonstration and testing campaign had the following objectives:

  • Collect sufficient radar data to enable evaluation of:
    • size/mass of bird targets,
    • distance to targets of different size/mass, and
    • capability of the radar in vertical as well as horizontal settings.
  • Collect data in a form that would allow standard postprocessing as well as output to GIS platforms.
  • Conduct demonstration and testing campaigns to collect coordinated radar and video data, supported by downrange recognition of bird targets.

An initial field campaign was completed in September 2004 at Dallas-Fort Worth (DFW) International Airport; a second campaign was completed in October 2005 at the Fermi National Accelerator Laboratory, Batavia, IL. Each field campaign involved opportunistic detection of bird movement, radar calibration and radar testing. In all cases, down-range observers provided confirmation of bird targets. Each campaign resulted in an integrated audio, video and paper record of all detections supported by calibration and testing of radar detection using defined targets. (Results of the 2004 demonstration and testing at DFW are available in a report published by the U. S. Air Force, Sensors Directorate, Rome Research Site as AFRL-SNRS- TR-2005-55. Reporting of the 2005 Fermilab demonstration and testing is currently in progress.)

General results are provided in Table 1. Detection of small, medium and large massed birds proved a success during the demonstrations. The BIRDAR prototype detected birds of different size/mass at varying ranges and operated well through both testing campaigns. Data from the radar was exported to a GIS platform to demonstrate alternate visualization schemes.

More information on BIRDAR is available through:

Federal Aviation Administration
William J. Hughes Technical Center
Atlantic City International Airport, NJ 08405
Tel: (609) 485-4000

Table 1: Demonstration and testing results for BIRDAR™
  Short Range 500 m Medium Range 500 m – 1.5 km Long Range 1.5 km
Small birds – single 400 g Confidence in detection Non-detection, additional testing needed Not Applicable
Small birds - flock Confidence in detection Confident in detection @ 1 - 1.2 km Non-detection
Medium Birds 400 g – 1.5 kg Confidence in detection Confident up to 1.2 km Non-detection
Large birds Confidence in detection Confidence in detection @ 1.5 km Detections @ 4 km


6. Clemson University Radar Ornithology Laboratory (CUROL)


CUROL developed the first BIRDRAD unit during the spring and summer of 1998 with funding from the Department of Defense Legacy Resource Management Program. First deployed successfully during the fall of 1998 at Howard Air Force Base in Panama, the radar system featured an off -the shelf Furuno FR-2155-an X-band, 50 kW, TR up unit.

At Howard Air Force Base, BIRDRAD easily detected dense movements of migrating hawks and vultures during daylight hours within six nautical miles, and songbird and other bird movements at night within three nautical miles.

With funding from Naval Facilities Engineering Command Field Activity Chesapeake (NAVFAC), CUROL updated BIRDRAD in August 1999 to a black-box version of the FR-2155. This new version provided enhanced display on a peripheral monitor. The unit was deployed at Patuxent River Naval Air Station, Maryland.

The next modification to BIRDRAD occurred in 2001. A Foresight Imaging HI*DEF Accura frame-grabber was bundled with Imaging Development Environment for Applications (IDEA) software in a PC to enable manual capture of any radar image as a.bmp file.

The new BIRDRAD unit was also equipped with a 24-inch parabolic antenna (four-degree beam width). Unlike open array antennas, the narrow, conical beam of the parabolic antenna provides accurate bird-target location within three-dimensions. The user-definable antenna angle is typically set between five and 30 degrees above the horizon to minimize ground clutter- returns from stationary targets such as buildings, towers, hills and trees.

The first of this new-generation BIRDRAD was deployed at Point Mugu Naval Air Station, California, in December 2001. Over the next year and a half, four additional units were deployed at Elmendorf Air Force Base, Alaska; Whidbey Island Naval Air Station, Washington; Cherry Point Marine Corp Air Station, North Carolina; and Patuxent River Naval Air Station, Maryland.

Within the last two years, the NAVFAC Shore Environmental R&D Program funded SSC-SD (Space and Naval Warfare Systems Command, San Diego) to help digitize and process raw BIRDRAD data and develop remote-control mechanisms. Sicom Systems Ltd. was contracted to undertake R&D and apply their ACCIPITER radar processor to:

  • reduce ground clutter;
  • detect, extract, identify, and track bird targets;
  • write processed data to a database; and
  • control radar remotely over a network.

The upgrade of BIRDRAD to eBIRDRAD on Patuxent River Naval Air Station began in the summer of 2004 and was completed in the spring of 2005. The unit is now being used in their bird-aircraft strike-hazard (BASH) program. In the fall of 2005, the BIRDRAD at Cherry Point Marine Corp Air Station was also upgraded to eBIRDRAD status.

For more information on BIRDRAD and eBIRDRAD:

Darnell, K.S.C. (1999) Winning the BASH War in Panama-
Sharing Lessons Learned.
Flying Safety Magazine 55 (9): 4-8

Dr. Sidney A. Gauthreaux, Jr.
Department of Biological Sciences
Clemson University Clemson, SC 29634-0314

7. EchoTrack Inc.

EchoTrack has developed a wildlife surveillance system that uses both radar and acoustics to assess collision risks. The system tracks flight paths of airborne wildlife (birds and bats) in three dimensions (using patented radar signal processing algorithms) and correlates them with acoustic data to identify species. The resulting data may help answer the pressing questions facing airport wildlife managers: Where and when is the risk of collision high? What are the conditions that increase the risk? What can be done to reduce them?

Based on conventional X-band marine grade radar with both transmission and signal processing modifications, the system is tuned and calibrated to monitor individual movements of even small birds and bats in all three dimensions, eliminating the need for, and limitations of, a second antenna. The system monitors the locations and altitudes of flight paths in a volume that is 4 km in diameter and up to 1,600 m high. Acoustic capture capability is both in the audible range (for birds) and ultrafrequency (for bats). A computerized console permits real-time monitoring but the EchoTrack system is also automated for 24/7 sampling. The resulting database is fully digitized for subsequent review, trend analysis and incident reporting.

In Alberta and Ontario, wind farm developers are using radaracoustic technology to measure and evaluate the response of birds and bats to the presence of a vertical planar threat; in their case, a wind turbine array. By following multiple flight paths the system determines the risk of a collision in a "zone of interference"; diff erent in shape but similar in concept, to a flight path.

EchoTrack has monitored bird and bat avoidance behavior on different landscapes, at various times of night, and during different seasons to determine-and enable prediction of-relative risk under various circumstances. In Alberta, for example, EchoTrack found that a very small proportion (1-2%) of wind turbines were associated with more than 80% of collisions. Managing conditions at these turbines substantially reduced the risk of collision. This capacity to identify high-risk areas and conditions could be equally beneficial for airport wildlife management.

Additionally, the species identification aspect of EchoTrack’s system enables wildlife personnel to enact species-specific control activities, increasing the effectiveness of mitigation and further reducing the risk of bird strikes.

For more information on EchoTrack:

Dr. Rhonda L. Millikin
EchoTrack Inc

8. Roadmap To The Future - 3D Airport Bird Detection Radar System

While private and public sector initiatives have demonstrated the potential of radar to greatly reduce bird hazards, most experts agree that radar systems capable of providing effective, three dimensional (3D) target determination will be required to fulfill the necessities of multiple-runway airports.

In January 2004, a report prepared by DeTect Inc, under contract to Transport Canada, was published as an internal guideline for the development of a 3D Airport Bird Detection Radar (3D ABDR) system at commercial airports in Canada. The report’s objective was to outline a roadmap for developing and fielding a 3D ABDR that would detect, track and monitor birds; improve airport wildlife management; and reduce aircraft-bird strike risk.

The report examined specifications and characteristics needed for an automated, real-time 3D-ABDR system that would:

  • accurately locate birds to a distance of five nautical miles and a height of 3000 feet AGL;
  • determine bird altitude, species, speed and size; and
  • issue warnings to pilots and wildlife-control offi cers based on the detected hazard.

Update - Health and Safety

Bird-radar systems exposure risks

Radar systems detect the presence, direction and range of moving objects by emitting pulses of high-frequency electromagnetic fields (EMFs). Radars usually operate at radio frequencies (RF) between 300MHz and 15GHz. Electromagnetic RF fields below 10 GHz (to 1 MHz) can penetrate exposed tissues and cause molecules in the tissue to vibrate and generate heat. Tissue absorption of RF fields is measured as the Specific Absorption Rate (SAR) of a given mass of tissue, usually expressed in W/kg (where W=power density). A SAR of at least 4W/kg is needed to produce known adverse health effects in the frequency range below 10 GHz. RF fields above 10 GHz are absorbed only at the skin surface. The intensity of fields in this frequency range is measured as power density per square metre (W/m2). Known adverse health effects, such as eye cataracts and skin burns, can occur when RF field exposure above 10GHz possesses power densities over 1000W/m2.

People who live or routinely work in radar-covered environments have expressed concerns about long-term adverse health effects, including cancer, reproductive malfunction, cataracts, and changes in behavior or development of children. However, international standards and protective measures-developed according to current available scientific evidence-limit human exposure to radar emissions. These standards also apply to bird radar systems, which produce relatively low RF environmental field levels and should not pose adverse health risks. To date, research has not found evidence of adverse health effects caused by multiple exposures to RF fields below threshold levels. Additionally, no evidence suggests that multiple low-level RF exposure results in accumulating damage.

For more information regarding radar safety:

Occupational Health and Safety Act

World Health Organization

Handling bird remains

Avian influenza is a contagious viral infection that can affect all species of birds, but can, less commonly, infect mammals. Due to natural resistance, wild bird species often carry influenza viruses without becoming ill. Domestic poultry flocks, however, are especially vulnerable to infection.

Avian influenza, although potentially fatal, is quite difficult for humans to contract. So far, most cases of bird-to-human transmission have involved people working in close proximity to large numbers of infected birds. Transmission is most likely to occur when infected bird droppings or bodily fluids come into contact with the mouth, or when infected airborne particles reach the eyes, mouth, or nose.

A single dead bird or small number of dead birds is unlikely to generate airborne particles; however, wildlife-control personnel are advised to wear non-permeable gloves and observe good hygiene when handling bird remains. Thorough handwashing, and effective disposal of the carcass, gloves, etc. in a sealed bag should be sufficient. If there is any concern about possible airborne particles, wear a facemask and safety glasses.

Persons who undertake activities with large numbers of birds in confined spaces (e.g., clearing pigeons from a roof ) should wear protective suits and respirators.

Regardless of the recent avian influenza outbreak, simple precautions should always be undertaken by anyone interacting with wildlife or handling dead animal matter.

For more information regarding avian influenza:

Health Canada

Public Health Agency of Canada

UK Health Protection Agency

US Center For Disease Control

Laser use

When using lasers in avian dispersal, operators target birds’ vision sensors. The repellent or dispersal effect of a laser is due to the intense and coherent mono-chromatic light that may have effects on bird behavior and may elicit changes in physiological processes.

Be sure to review the following Canadian Aviation Regulations before adding laser dispersal to an airport wildlife-management portfolio:

Projection of Directed Bright Light Source at an Aircraft 601.20

Subject to section 601.21, no person shall project or cause to be projected a bright light source into navigable airspace in such a manner as to create a hazard to aviation safety or cause damage to an aircraft or injury to persons on board the aircraft.

Requirement for Notifi cation 601.21

  1. Any person planning to project or cause to be projected a directed bright light source into navigable airspace with sufficient power to create a hazard to aviation safety shall provide written notification to the Minister before the projection.
  2. On receipt of the notification, the Minister may issue an authorization if the projection of the directed bright light source is not likely to create a hazard to aviation safety.

Requirement for Pilot-in-command 601.22

  1. No pilot-in-command shall intentionally operate an aircraft into a beam from a directed bright light source or into an area where a directed bright light source is projected, unless the aircraft is operated in accordance with an authorization issued by the Minister
  2. The Minister may issue the authorization if the operation of the aircraft is not likely to create a hazard to aviation safety.

For more information:

Canadian Aviation Regulations

United States Department of Agriculture (APHIS)

For more information on content in this bulletin, please contact:

Wildlife Management Specialist
Flight Standards, Transport Canada
Place de Ville, Tower C
Ottawa, ON
K1A 0N8