Ultrasonic bird repellent devices (UBRDs) promise a quiet way to keep birds away by emitting very high frequency sound above 20 kHz, but their effectiveness is often questioned. This article summarizes independent studies and authoritative reviews that synthesize prior research, explaining what was tested, how it was tested, and what happened.
Woronecki: Effect of Ultrasonic, Visual, and Sonic Devices on Pigeon Numbers in a Vacant Building
What was tested and how
Researchers evaluated three scaring devices inside an empty multi storey building that housed a resident feral pigeon population. The ultrasonic unit was run in two operating modes during a 20 day treatment. Counts of pigeons were made during pre, treatment, and post treatment periods. (Source)
What happened
- The study’s abstract states: “The ultrasonic device was completely ineffective.”
- The ultrasonic unit showed no change in pigeon activity during its 20 day run.
- Pigeons did not avoid places where the ultrasonic field was strongest and even built nests within about 7 to 20 metres of the operating unit.
- Post treatment counts were essentially unchanged, with totals of about 75 birds for continuous mode and about 73 for pulsed mode.
Bottom line: In this controlled building trial, ultrasonics did not reduce pigeon numbers.
Griffiths: Efficacy Testing of an Ultrasonic Bird Repeller
What was tested and how
A commercial device that combined audible and ultrasonic outputs was set up at feeding sites baited with sunflower seeds. Researchers compared bird activity, time spent feeding, and the amount of seed eaten at a treated site versus a matched control site. They also checked an unbaited site to see whether the device altered general bird use of the area. (Source)
What happened
- Across the common species present, no significant differences in activity or feeding were detected between treated and control sites.
- The device also did not change bird behaviour at the unbaited site.
Bottom line: In side by side field comparisons, the combination sonic ultrasonic unit did not measurably deter birds.
Beuter and Weiss: Properties of the Auditory System in Birds and the Effectiveness of Acoustic Scaring Signals
What was tested and how
This paper had two parts (Source):
- Hearing tests. The team measured midbrain evoked potentials in gulls to map hearing thresholds from 1 to 25 kHz.
- Field test. At a municipal purification plant with many free living gulls, the researchers placed sound sources close to the birds and broadcast ultrasound, infrasound, and audible signals at high intensities. Equipment was staged days in advance so birds were accustomed to the hardware. They then observed changes in use of the area.
What happened
- Physiological thresholds showed very poor sensitivity above roughly 11 kHz, which excludes ultrasonic hearing.
- In the field, ultrasound and infrasound did not produce a scaring effect. Only certain frequency modulated audible signals affected gull behaviour.
Bottom line: The hearing data and field observations both point the same way. Ultrasound was inaudible to the study birds and failed to scare them.
Jenni Eiermann, Heynen and Schaub: Effect of an Ultrasonic Device on the Behaviour and the Stress Hormone Corticosterone in Feral Pigeons
What was tested and how
The authors ran two complementary tests with a commercially used ultrasonic system (Source):
- Caged pigeons. Birds were exposed to the device while their behaviour was video recorded and their stress physiology was measured using blood corticosterone sampling.
- Free living pigeons. An ultrasonic loudspeaker was mounted at a dovecote entrance in Lucerne. A metal plate behind the speaker directed sound away from birds inside, creating a quieter shadow while still flooding the approach with ultrasound. Researchers photographed the entrance platform at set intervals and counted how many pigeons used it under on and off cycles of the device.
What happened
- In cages, no change in behaviour or corticosterone levels was detected during ultrasonic exposure.
- At the dovecote, pigeons used the entrance regularly regardless of whether the device was running, and no deterrent effect was seen.
Bottom line: Carefully measured behaviour and physiology showed no repellent effect from ultrasound on feral pigeons.
Transport Canada: Evaluation of the Efficacy of Products and Techniques for Airport Bird Control
What it is
A government evaluation of bird control products and techniques for airports. (Source)
Ultrasonic section verdict
Ultrasound is not an effective bird deterrent and is not recommended for airport wildlife control. The report cites the hearing limits of birds and negative device tests, including Woronecki and Griffiths.
Bottom line: National level guidance advises against ultrasonic devices for birds.
Airport Cooperative Research Program: Bird Harassment, Repellent, and Deterrent Techniques for Use on and Near Airports
What it is
A National Academies synthesis of techniques for airports. (Source)
Ultrasonic conclusion
Ultrasonic devices are unlikely to be a viable option for birds and past field tests have not shown success.
Bottom line: Independent synthesis reaches the same conclusion as Transport Canada.
U.S. Air Force: Ultrasonics as a Method of Bird Control
What it is
A technical review that examined published trials of ultrasonic bird repelling devices (UBRDs). (Source)
Conclusion
No meaningful reductions in bird numbers from ultrasonic devices. The review questioned the plausibility of ultrasonic bird control given avian hearing limits.
Bottom line: Aligns with later government and academic reviews that do not recommend ultrasonic devices for birds.
Why These Results Are Consistent With Bird Hearing
Independent summaries of avian bioacoustics show that birds generally do not hear true ultrasound and are most sensitive to lower frequencies. According to USDA National Wildlife Research Center, most birds hear best around 1 to 5 kHz, have very poor sensitivity above about 10 kHz, and that audibility depends on species, loudness, distance, and background noise. These points explain why a purely ultrasonic output is unlikely to repel birds.
Takeaway
Across multiple controlled tests and government reviews, the effectiveness of ultrasonic bird repellent is not supported. Most birds hear best around 1 to 5 kHz and have poor sensitivity at ultrasonic pitches, which helps explain the field results. Some products marketed as ultrasonic also emit audible sound. Any initial response is likely due to the audible part, and birds often habituate to sound-based bird deterrents.
Where Rise Tape Fits
If you need a non-audible, unobtrusive option to discourage perching and roosting, Rise Tape is a visual deterrent that uses movement and light reflections to make perching and nesting less attractive. It can be one part of an integrated plan where sound has not produced lasting results. If you want help deciding if it fits your site, we can walk through placement and coverage.