Hummingbirds are known for their ability to hover in midair and fly backwards, but some species also make a distinct clicking or rattling sound with their wings. This sound is related to the aerodynamics of hummingbird flight and serves an important purpose for the birds.
Why Do Hummingbirds Make a Clicking Sound?
According to ornithologists and researchers, there are a couple reasons hummingbirds make a clicking or rattling noise with their wings:
- It’s caused by airflow over the wings when the bird is courting, defending territory, or engaging in aerial displays
- The sound occurs when the wings beat at high frequencies around 20-80 times per second
- As the wings flap at rapid speeds, air rushing over the feathers causes tiny vortices and turbulence
- The collision of these air currents produces the clicking or rattling noise
Additionally, the noise may play a role in communication and display between hummingbirds. The male Anna’s hummingbird, in particular, makes a loud whistling sound with its tail feathers during its elaborate diving courtship display. The clicking noise of the wings could add to this visual display to impress potential mates or ward off competitors.
Which Species of Hummingbirds Make This Sound?
There are over 300 species of hummingbirds worldwide, but only some have been documented to produce clicking or rattling sounds in flight. Some species known for this include:
- Anna’s hummingbird (Calypte anna)
- Costa’s hummingbird (Calypte costae)
- Allen’s hummingbird (Selasphorus sasin)
- Streamertail hummingbird (Trochilus scitulus)
- Black-chinned hummingbird (Archilochus alexandri)
- Broad-tailed hummingbird (Selasphorus platycercus)
Of these, Anna’s and Allen’s hummingbirds are among the most vocal and produce the loudest clicking sounds. Their rapid wing beats and aerobatics involved in courtship displays may contribute to the prominence of the sound.
When and Why Do They Produce the Sound?
Hummingbirds appear to produce clicking wing sounds in the following contexts:
- Courtship Displays: Many hummingbird species perform elaborate courtship rituals to attract mates. The male flies in loops, dives, and hovers near the female. The sounds made by their wings add to the display.
- Territorial Defense: Hummingbirds are very territorial, especially when defending a food source. The clicking sounds communicate a warning to intruders.
- Chasing: A hummingbird may produce clicking sounds when chasing another bird from a feeder or territory.
- Alarm: The birds sometimes make a rattling sound with their wings when alarmed or distressed.
Research indicates the following primary reasons they use clicking wing sounds for communication:
- To demonstrate fitness during courtship
- To startle, intimidate, or chase away competitors
- To signal distress or alarm
- To exaggerate and call attention to aerial maneuvers
The sounds emphasize dynamic motions and may provide information on the bird’s health, skill, strength, and motivation.
Are the Sounds Only Made During Flight?
Hummingbirds only produce clicking or rattling wing sounds while in flight. The aerodynamics of air rushing over their wings at rapid speeds causes the noises. When perched or at rest, they do not make these sounds.
However, hummingbirds can and do produce other vocalizations when sitting still. These can include:
- Squeaks
- Cheeps
- Whistles
- Chirps
- Trills
These sounds are made vocally through the syrinx rather than with their wings. The syrinx is the avian equivalent of the human larynx or voice box.
Measuring the Frequency of Hummingbird Clicking
Scientists have measured the frequency of hummingbird wings flapping to produce the clicking sounds. Here are some examples of the beats per second recorded in different species:
- Ruby-throated hummingbird: 24 beats/second
- Black-chinned hummingbird: 27 beats/second
- Anna’s hummingbird: 48 beats/second
- Costa’s hummingbird: 55 beats/second
- Broad-tailed hummingbird: up to 80 beats/second
In general, the larger the hummingbird species, the slower the wing beat required for hovering and clicking sounds. Larger wings move more air with each flap compared to smaller wings. The smallest species, like bee hummingbirds, can beat up to 200 times per second!
Table – Hummingbird species and their average wing beat frequencies
Species | Average Wing Beat Frequency |
---|---|
Ruby-throated Hummingbird | 24 beats/second |
Black-chinned Hummingbird | 27 beats/second |
Anna’s Hummingbird | 48 beats/second |
Costa’s Hummingbird | 55 beats/second |
Broad-tailed Hummingbird | Up to 80 beats/second |
Acoustics and Mechanics of the Sound
The exact mechanics behind the clicking and rattling sounds hummingbirds generate mid-flight requires further study. But researchers suggest a few factors that contribute to the acoustics:
- As the wings flap at high speeds, tiny eddies and vortices in the air currents collide and pop.
- The tips of the wings likely snap and cause air to rush through the primary feathers.
- This turbulence and popping in the airflow creates the clicking sounds.
- The flexible feathers and their ability to twist and flutter likely accentuate the noise.
The speed, angle, and motion of the wings as they beat and rotate can all affect the volume and intensity of the sounds produced. There may also be subtle differences in the wing anatomy of species that click more prominently during flight.
The Evolutionary Advantage of Clicking Wings
Most ornithologists agree that the clicking or rattling wing sounds evolved to serve a purpose for hummingbirds. Possible advantages include:
- Communication – The sounds amplify visual courtship displays or territorial displays to other birds.
- Scaring Competitors – Rival males may be startled by the sounds and leave an area.
- Drawing Attention – Females are alerted to impressive aerial maneuvers and fitness.
- Aerodynamics – There may be subtle flight improvements such as stability from the wing movements.
In species like Anna’s hummingbird where males perform complex dive displays during courtship, the clicking sounds likely helped reinforce mating signals and improved reproductive success over time.
Threats to Hummingbirds That Vocalize
Hummingbirds that use clicking wing sounds may face some risks including:
- Energy costs – Producing the sounds requires rapid wing beats which expend more energy.
- Increased predation risk – The sounds may attract predators or reveal the bird’s presence.
- Hearing damage – Loud hummingbird vocalizations are over 100 dB SPL. This can temporarily impact their hearing.
However, the benefits of making the sounds likely outweighed the potential costs as the behavior evolved. Strategic use of clicking noise only in short bursts probably minimizes any threats for hummingbirds.
Differences Between Wing Clicking and Vocalizations
The clicking or rattling noises made by the wings differ from vocal hummingbird calls and chirps. Key differences include:
- Source: Wing sounds are mechanical while vocalizations come from the syrinx.
- Context: Clicks occur during flight only but calls happen while perched.
- Volume: Vocalizations are generally louder than the subtle wing clicks.
- Pitch: Calls have a wider frequency range compared to uniform clicking.
Understanding these distinctions can help birders identify the unique sounds hummingbirds produce and why they make them.
Recording and Identifying Hummingbird Wing Sounds
Catching the subtle clicking sounds hummingbird wings make midair on recording equipment can be challenging. But here are some tips for capturing the noise:
- Use a parabolic microphone for best results in isolation and directionality.
- Aim for areas where males court, display, and chase to increase likelihood of recording the sounds.
- Pay attention to dive bombing display behaviors to anticipate clicking bursts.
- Consider attaching small microphones directly near hummingbird feeders.
- Use audio software to amplify and isolate the subtle wing click sounds.
Focusing on territorial males during peak mating seasons offers your best chance to detect and analyze the wing clicking phenomena in hummingbirds.
Conclusion
The clicking and rattling sounds some hummingbird species make while in flight arise from the aerodynamics of rapid wing beats. As air flows over the wings at speeds over 50 flaps per second in courtship displays, the turbulence creates noticeable sounds. Ornithologists think male hummingbirds leverage these wing clicks to communicate with mates and competitors. Next time you hear a persistent clicking around a hummingbird, listen closely to identify which species it may be and why the bird is vocalizing.