The Broad-tailed Hummingbird (Selasphorus platycercus) is a small hummingbird found in the western United States. Like all hummingbirds, the Broad-tailed Hummingbird has a very distinctive sound that it uses for communication.
Typical Sounds
The most common sound made by the Broad-tailed Hummingbird is the humming created by its rapidly beating wings. The wings of hummingbirds beat incredibly fast, with the Broad-tailed Hummingbird’s wings beating up to 80 times per second. This rapid wingbeat creates the characteristic humming sound that gives hummingbirds their name.
The typical frequency of the wing hum of the Broad-tailed Hummingbird ranges from around C5 to D7 on the musical scale, with the dominant frequency being around F6. This corresponds to a frequency range of approximately 523 Hz to 2349 Hz. The changing pitch of the wing hum is caused by the bird modulating the wingbeat frequency as it hovers and moves.
In addition to the wing hum, Broad-tailed Hummingbirds also make chirping and twittering sounds with their voices. These vocalizations are higher-pitched, shorter, and less melodious than the songs of many other birds. The chirps are very high-frequency, often around 6-10 kHz in range. They are used for communicating with other individuals nearby.
Courtship Sounds
During courtship and mating, male Broad-tailed Hummingbirds produce a distinctive buzzing sound with their tail feathers. This is sometimes referred to as a “bee-buzzing” sound. It is made by vibrating the tail feathers very quickly while flying high speed dive displays.
To make the buzzing sound, the outer tail feathers of the male Broad-tailed Hummingbird are flared out and held at an angle to the tail. Air flows through the spread tail feathers and causes them to flutter and vibrate, creating the buzzing sound. The pitch is a function of the vibration frequency, which can be over 100 Hz.
Research has found that each male Broad-tailed Hummingbird has a slightly different and unique buzzing sound based on the specifics of its tail feathers. Females are thought to recognize the buzz of their mate based on these individual differences. The tail-buzzing sound signals the male’s fitness during courtship.
Distress Calls
When threatened by predators or distressed, Broad-tailed Hummingbirds will make sharp, squeaking alarm calls. These distress calls are short, loud, high-pitched sounds that can signal danger to other birds nearby. The frequency of distress calls is typically in the 5-8 kHz range.
Some common predators of Broad-tailed Hummingbirds include falcons, hawks, roadrunners, snakes, and cats. Distress calls alert these predators that the hummingbird is aware of their presence. They also communicate to other hummingbirds in the area that a threat is present.
Chatter Sounds
At their nests and feeding sites, male Broad-tailed Hummingbirds are known to make extended series of chatter-like sounds when interacting with females and juveniles. These vocalizations include a mix of tik and tok sounds in quick succession.
Researchers believe the chatter vocalizations help communicate the male’s dominance and serve as a territorial warning against intruders. The rapid chatter sounds signal the male’s willingness to chase away competitors at food sources or nest sites.
High-Speed Sounds
When diving through the air at high speeds, Broad-tailed Hummingbirds make unique sounds described as squeaky or whistle-like. These sounds are thought to be caused by the interaction of air currents over the hummingbird’s tail feathers and wings.
During courtship displays, male Broad-tailed Hummingbirds will climb very high in the air before diving down at great speed past the female. The rapid diving creates high-pitched whining and whistling sounds as the hummingbird slices through the air.
Frequency Range
By compiling the various sounds made by the Broad-tailed Hummingbird during different behaviors, we can determine the overall frequency range of its vocalizations:
- Wing hum: 523 Hz to 2349 Hz dominant at 659 Hz
- Chirps: 6 kHz to 10 kHz range
- Tail buzzing: Over 100 Hz
- Distress calls: 5 kHz to 8 kHz range
- Diving sounds: 1 kHz to 8 kHz range
This gives the Broad-tailed Hummingbird a total vocalization frequency range of approximately 100 Hz at the low end up to 10 kHz at the high end, spanning nearly four octaves.
Pitch and Timbre
The pitch of Broad-tailed Hummingbird vocalizations is distinctly high due to the tiny size of the birds. Smaller vocal anatomy means higher frequency sounds.
Most of the sounds are pure tones without complexity or modulation. However, the wing hum contains harmonic overtones that give it a distinctive timbre. The tail buzzing also has a pronounced timbre quality that radiates the buzzing effect.
The rapid chirping sounds are very short and do not sustain long enough to have a strong pitch or harmonic quality. They are simply very high-frequency spikes of sound.
Purpose of Sounds
The various vocalizations of the Broad-tailed Hummingbird serve different communication purposes:
- Wing hum – Maintains flight and signals presence
- Chirps – Close range communication
- Tail buzzing – Courtship display by males
- Distress calls – Predator warning signal
- Chatter – Territorial defense at resources
- Diving sounds – Part of courtship display
By using diverse sounds in specific behavioral contexts, Broad-tailed Hummingbirds are able to effectively communicate despite their very small size.
Variation Between Individuals
There is some moderate individual variation in the details of the sounds produced by different Broad-tailed Hummingbirds. Some sources of variation can include:
- Exact wingbeat frequency based on body size and age
- Pitch of chirps linked to voice box size
- Differences in tail feather shape affecting buzzing
- Small differences in alarm call pitch
However, the overall nature and frequency ranges of the vocalizations is relatively constant across the species. The differences are minor compared to the wide variation in songs between songbird species.
Variation in Sound by Season and Habitat
The sounds made by Broad-tailed Hummingbirds can vary somewhat based on season and habitat:
- In the breeding season, males make more buzzing sounds during courtship displays
- Chatter sounds are more common around nests and at flowers during the summer
- Alarm calls are heard more often in dense forests due to more predators
- The pitch of wing hums may change with air temperature differences
However, the basic repertoire of sounds are consistent across habitats and seasons. Only the frequency of each sound changes based on context.
Similarity to Sounds of Other Hummingbird Species
The sounds of the Broad-tailed Hummingbird share many similarities with other hummingbird species that are closely related or similar in size, such as:
- Rufous Hummingbird
- Allen’s Hummingbird
- Calliope Hummingbird
These species produce similar high-pitched chirps, wing buzzing, whistling flight sounds, and high-frequency chatter. The greatest difference is in the pitch of courtship buzzing, which varies by tail feather shape.
In contrast, larger hummingbird species such as the Giant Hummingbird have lower-pitched and slower wing beats. Smaller species have higher-pitched sounds. But across all hummingbirds, the types of sounds made are very similar.
Mimicry By Other Bird Species
Some other bird species are able to mimic the sounds of the Broad-tailed Hummingbird by modifying their vocalizations. For example:
- European Starling – Able to mimic humming and chirping sounds
- Northern Mockingbird – Copies chirps and buzzing sounds
- Brewer’s Blackbird – Mimics simple chirps
Mimicking hummingbird sounds may enable these species to deceive other birds during competitions for food and resources. However, the mimicry is limited to simple sounds like chirps rather than elaborate mimicked songs.
Recordings and Sonograms
Here are examples of audio recordings of Broad-tailed Hummingbird vocalizations with corresponding sonogram images showing the sound waveforms:
Wing Hum
| Audio | |
| Sonogram |
Chirps
| Audio | |
| Sonogram |
Tail Buzzing
| Audio | |
| Sonogram |
Conclusion
In summary, the Broad-tailed Hummingbird produces a wide variety of sounds from wing hums to courtship buzzes that span a frequency range of 100 Hz to 10 kHz. The purpose of these vocalizations is communication during behaviors such as courtship, territorial defense, and predator avoidance. While there are small individual differences, the sounds are generally consistent across the species and season. Understanding the sounds of the Broad-tailed Hummingbird provides insight into the lives of these vocal creatures.
