Coos, booms, and hoots: The evolution of closed‐mouth vocal behavior in birds

@article{Riede2016CoosBA,
  title={Coos, booms, and hoots: The evolution of closed‐mouth vocal behavior in birds},
  author={Tobias Riede and Chad M. Eliason and Edward H. Miller and Franz Goller and Julia A. Clarke},
  journal={Evolution},
  year={2016},
  volume={70}
}
Most birds vocalize with an open beak, but vocalization with a closed beak into an inflating cavity occurs in territorial or courtship displays in disparate species throughout birds. Closed‐mouth vocalizations generate resonance conditions that favor low‐frequency sounds. By contrast, open‐mouth vocalizations cover a wider frequency range. Here we describe closed‐mouth vocalizations of birds from functional and morphological perspectives and assess the distribution of closed‐mouth vocalizations… 

Vocal specialization through tracheal elongation in an extinct Miocene pheasant from China

TLDR
A fossil skeleton of a new extinct species of wildfowl from the late Miocene of China, preserves an elongated, coiled trachea that represents the oldest fossil record of this vocal modification in birds and the first documentation of its evolution within pheasants.

The early origin of a birdlike inner ear and the evolution of dinosaurian movement and vocalization

TLDR
Three-dimensional morphometric analyses of a large sample of extant and extinct reptiles to investigate inner ear correlates of locomotor ability and hearing acuity revealed three vestibular morphotypes, best explained by three locomotor categories—quadrupeds, bipeds and simple fliers (including bipedal nonavialan dinosaurs), and high-maneuverability fliers.

Pervasive low‐frequency vocal modulation during territorial contests in Eurasian Scops Owls ( Otus scops )

TLDR
Investigating territorial interactions between male Eurasian Scops Owls that occupy territories in a densely-packed area revealed context-dependent fluctuations in hoot frequency, which may suggest that the hoot of the Scops Owl dynamically reflects the current motivational state of the caller during the contest.

Fossil evidence of the avian vocal organ from the Mesozoic

TLDR
The first remains, to the authors' knowledge, of a fossil syrinx from the Mesozoic Era are described, preserved in three dimensions in a specimen from the Late Cretaceous of Antarctica and show the fossilization potential of the avian vocal organ and beg the question why these remains have not been found in other dinosaurs.

Vocalization with semi-occluded airways is favorable for optimizing sound production

TLDR
For human vocalization described here, special emphasis is placed on the epilaryngeal airway, which can be adjusted for optimal aerodynamic power transfer and for optimal acoustic source-airway interaction.

Vocal and non-vocal behavior interact differently in territorial strategies of two sympatric Rallidae species

TLDR
While settling territorial conflicts, Water Rails utilized a purely signaling strategy involving reliable vocal signals and thus the avoidance of direct actions, whereas Little Crakes relied primarily on direct actions.

The evolution of the syrinx: An acoustic theory

TLDR
Testing the hypothesis that the syrinx constitutes a biomechanical advantage for sound production over the larynx with combined theoretical and experimental approaches provides compelling evidence that strong selective pressures for high vocal efficiency may have been a major driving force in the evolution of a syrinX.

Tonality over a broad frequency range is linked to vocal learning in birds

TLDR
Assessing tonality of song syllables between vocal learners and non-learners suggests that vocal learners in both clades have evolved to sing songs with higher tonality than the related, non-vocal learning clades, which is consistent with stronger roles for broadband dynamic filtering and adjustments to the sound source.

A global analysis of song frequency in passerines provides no support for the acoustic adaptation hypothesis but suggests a role for sexual selection

TLDR
The results suggest that the global variation in passerine song frequency is mostly driven by natural and sexual selection causing evolutionary shifts in body size rather than by habitat-related selection on sound propagation.

On the natural history of duetting in White-browed Coucals: sex- and body-size-dependent differences in a collective vocal display

TLDR
The structure and performance rules of duets in White-browed Coucals Centropus superciliosus, a tropical non-parasitic Cuckoo is described, finding that duet contributions were sex specific with females producing lower-pitched songs than males, reflecting the general size dimorphism in this species.

References

SHOWING 1-10 OF 158 REFERENCES

Vocal tract articulation revisited: the case of the monk parakeet

TLDR
X-ray cinematographic imaging of naturally vocalizing monk parakeets was used to assess which articulators are possibly involved in vocal tract filtering in this species, and strong positive correlations between beak opening and amplitude as well as changes in tongue height and amplitude in several types of vocalization were found.

Acoustic exaggeration of size in birds via tracheal elongation: comparative and theoretical analyses

TLDR
It is proposed that tracheal elongation serves to exaggerate the apparent size of a vocalizing bird, and this ‘size exaggeration’ hypothesis is found to be consistent with current theories of avian vocal production and a wide range of comparative ecological and behavioural data.

On the existence and potential functions of low-amplitude vocalizations in North American birds

TLDR
Survey of the existence and putative functions of low-amplitude vocalizations across 749 species accounts of breeding birds in North America suggests that low- AMP vocalizations are common at a broad taxonomic scale, and that low/novel songs may be a distinct class of vocal signal.

Vocal Tract Articulation in Zebra Finches

TLDR
These findings confirm that birds can modulate their song by using vocal tract filtering and demonstrate how OEC and beak gape contribute to this modulation.

Songbirds tune their vocal tract to the fundamental frequency of their song.

TLDR
Through x-ray cinematography of singing birds, it is shown that birdsong is accompanied by cyclical movements of the hyoid skeleton and changes in the diameter of the cranial end of the esophagus that maintain an inverse relationship between the volume of the oropharyngeal cavity and esophagi and the song's fundamental frequency.

Subglottal pressure and fundamental frequency control in contact calls of juvenile Alligator mississippiensis

TLDR
The morphological and physiological features of sound production in alligators are investigated and it is concluded that the alligator larynx represents a sound source with only two control parameters (subglottal pressure and vocal fold adduction) in contrast to the mammalian larynX in which three parameters can be altered to modulate frequency.

The acoustic effect of vocal tract adjustments in zebra finches

TLDR
The spectral emphasis during zebra finch call production ranging between 2.5 and 5 kHz was not present during respiratory sounds, indicating strongly that it can be attributed to the OEC expansion.

Vocal tract resonances in oscine bird sound production: evidence from birdsongs in a helium atmosphere

TLDR
Not only does the songbird's vocal tract act as an acoustic filter, but its filter characteristics are actively coordinated with the output of the syrinx, suggesting that birdsong and human phonation are more analogous than previously thought.

Model for vocalization by a bird with distensible vocal cavity and open beak.

TLDR
It is shown that the resonance of the oropharyngeal-esophageal cavity, vented through the beak, introduces a dominant peak in the radiation efficiency, the frequency of which can be adjusted by varying the volume of the cavity, theBeak gape, and perhaps the position of the tongue in the mouth.

Lingual articulation in songbirds

TLDR
Results suggest that tongue elevation lowers the resonance frequency below 2 kHz by reducing the area of the passage from the oral cavity into the beak, consistent with a computational model of the songbird vocal tract in which resonance frequencies are actively adjusted.
...