scholarly journals A Call to Expand Avian Vocal Development Research

2021 ◽  
Vol 9 ◽  
Author(s):  
Yen Yi Loo ◽  
Kristal E. Cain

Birds are our best models to understand vocal learning – a vocal production ability guided by auditory feedback, which includes human language. Among all vocal learners, songbirds have the most diverse life histories, and some aspects of their vocal learning ability are well-known, such as the neural substrates and vocal control centers, through vocal development studies. Currently, species are classified as either vocal learners or non-learners, and a key difference between the two is the development period, extended in learners, but short in non-learners. But this clear dichotomy has been challenged by the vocal learning continuum hypothesis. One way to address this challenge is to examine both learners and canonical non-learners and determine whether their vocal development is dichotomous or falls along a continuum. However, when we examined the existing empirical data we found that surprisingly few species have their vocal development periods documented. Furthermore, we identified multiple biases within previous vocal development studies in birds, including an extremely narrow focus on (1) a few model species, (2) oscines, (3) males, and (4) songs. Consequently, these biases may have led to an incomplete and possibly erroneous conclusions regarding the nature of the relationships between vocal development patterns and vocal learning ability. Diversifying vocal development studies to include a broader range of taxa is urgently needed to advance the field of vocal learning and examine how vocal development patterns might inform our understanding of vocal learning.

2006 ◽  
Vol 2 (4) ◽  
pp. 509-512 ◽  
Author(s):  
Andrew D Foote ◽  
Rachael M Griffin ◽  
David Howitt ◽  
Lisa Larsson ◽  
Patrick J.O Miller ◽  
...  

The production learning of vocalizations by manipulation of the sound production organs to alter the physical structure of sound has been demonstrated in only a few mammals. In this natural experiment, we document the vocal behaviour of two juvenile killer whales, Orcinus orca , separated from their natal pods, which are the only cases of dispersal seen during the three decades of observation of their populations. We find mimicry of California sea lion ( Zalophus californianus ) barks, demonstrating the vocal production learning ability for one of the calves. We also find differences in call usage (compared to the natal pod) that may reflect the absence of a repertoire model from tutors or some unknown effect related to isolation or context.


2021 ◽  
Vol 7 (20) ◽  
pp. eabe2405
Author(s):  
Henrik Brumm ◽  
Wolfgang Goymann ◽  
Sébastien Derégnaucourt ◽  
Nicole Geberzahn ◽  
Sue Anne Zollinger

Noise pollution has been linked to learning and language deficits in children, but the causal mechanisms connecting noise to cognitive deficiencies remain unclear because experimental models are lacking. Here, we investigated the effects of noise on birdsong learning, the primary animal model for vocal learning and speech development in humans. We found that traffic noise exposure retarded vocal development and led to learning inaccuracies. In addition, noise suppressed immune function during the sensitive learning period, indicating that it is a potent stressor for birds, which is likely to compromise their cognitive functions. Our results provide important insights into the consequences of noise pollution and pave the way for future studies using birdsong as an experimental model for the investigation of noise-induced learning impairments.


Development ◽  
1994 ◽  
Vol 120 (1) ◽  
pp. 13-24
Author(s):  
F. Johnson ◽  
S. W. Bottjer

Forebrain nuclei that control learned vocal behavior in zebra finches are anatomically distinct and interconnected by a simple pattern of axonal pathways. In the present study, we examined afferent regulation of neuronal survival during development of the robust nucleus of the archistriatum (RA). RA projection neurons form the descending motor pathway of cortical vocal-control regions and are believed to be directly involved in vocal production. RA receives afferent inputs from two other cortical regions, the lateral magnocellular nucleus of the anterior neostriatum (lMAN) and the higher vocal center (HVC). However, because the ingrowth of HVC afferent input is delayed, lMAN projection neurons provide the majority of afferent input to RA during early vocal learning. lMAN afferent input to RA is of particular interest because lMAN is necessary for vocal learning only during a restricted period of development. By making lesions of lMAN in male zebra finches at various stages of vocal development (20-60 days of age) and in adults (>90-days old), we asked whether the survival of RA neurons depends on lMAN afferent input, and if so whether such dependence changes over the course of vocal learning. The results showed that removal of lMAN afferent input induced the loss of over 40% of RA neurons among birds in early stages of vocal development (20 days of age). However, lMAN lesions lost the ability to induce RA neuron death among birds in later stages of vocal development (40 days of age and older). These findings indicate that many RA neurons require lMAN afferent input for their survival during early vocal learning, whereas the inability of lMAN lesions to induce RA neuron death in older birds may indicate a reduced requirement for afferent input or perhaps the delayed ingrowth of HVC afferent input (at approx. 35 days of age) provides an alternate source of afferent support. Removal of lMAN afferent input also dramatically increased the incidence of mitotic figures in RA, but only among 20-day-old birds at 2 days post-lesion. The early, acute nature of the mitotic events raises the possibility that cell division in RA may be regulated by lMAN afferent input.


2020 ◽  
Vol 16 (4) ◽  
pp. 20190928 ◽  
Author(s):  
Ella Z. Lattenkamp ◽  
Sonja C. Vernes ◽  
Lutz Wiegrebe

Vocal production learning (VPL), or the ability to modify vocalizations through the imitation of sounds, is a rare trait in the animal kingdom. While humans are exceptional vocal learners, few other mammalian species share this trait. Owing to their singular ecology and lifestyle, bats are highly specialized for the precise emission and reception of acoustic signals. This specialization makes them ideal candidates for the study of vocal learning, and several bat species have previously shown evidence supportive of vocal learning. Here we use a sophisticated automated set-up and a contingency training paradigm to explore the vocal learning capacity of pale spear-nosed bats. We show that these bats are capable of directional change of the fundamental frequency of their calls according to an auditory target. With this study, we further highlight the importance of bats for the study of vocal learning and provide evidence for the VPL capacity of the pale spear-nosed bat.


Author(s):  
Samantha Carouso Peck ◽  
Michael H. Goldstein

The social environment plays an important role in vocal development. In songbirds, social interactions that promote vocal learning are often characterized by contingent responses of adults to early, immature vocalizations. Parallel processes have been discovered in the early speech development of human infants. Why does contingent social feedback facilitate vocal learning so effectively? Answers may be found by connecting the neural mechanisms of vocal learning and control with those involved in processing social reward. This chapter extends the idea of Newman’s social behaviour network, a tightly interconnected system of limbic areas across which social behaviour and motivation are distributed, to an avian social/vocal control network. It explores anatomical and functional overlaps between song circuitry and social-motivational circuitry, describing how circuitry linking basal ganglia with cortical areas serves to integrate social reward with vocal control and may underlie socially guided vocal learning. In species that have evolved socially guided vocal learning, a unique link has been forgedbetween social circuitry and vocal learning systems, such that learning is driven by social motivation.


1996 ◽  
Vol 351 (1345) ◽  
pp. 1341-1348 ◽  

Several empirical models have attempted to account for the covariation among life history traits observed in a variety of organisms. One of these models, the fast-slow continuum hypothesis, emphasizes the role played by mortality at different stages of the life cycle in shaping the large array of life history variation. Under this scheme, species can be arranged from those suffering high adult mortality levels to those undergoing relatively low adult mortality. This differential mortality is responsible for the evolution of contrasting life histories on either end of the continuum. Species undergoing high adult mortality are expected to have shorter life cycles, faster development rates and higher fecundity than those experiencing lower adult mortality. The theory has proved accurate in describing the evolution of life histories in several animal groups but has previously not been tested in plants. Here we test this theory using demographic information for 83 species of perennial plants. In accordance with the fast-slow continuum, plants undergoing high adult mortality have shorter lifespans and reach sexual maturity at an earlier age. However, demographic traits related to reproduction (the intrinsic rate of natural increase, the net reproductive rate and the average rate of decrease in the intensity of natural selection on fecundity) do not show the covariation expected with longevity, age at first reproducion and life expectancy at sexual maturity. Contrary to the situation in animals, plants with multiple meristems continuously increase their size and, consequently, their fecundity and reproductive value. This may balance the negative effect of mortality on fitness, thus having no apparent effect in the sign of the covariation between these two goups of life history traits.


Author(s):  
Carel ten Cate

The study of vocal production learning in birds is heavily biased towards oscine songbirds, making the songbird model the reference for comparative studies. However, as vocal learning was probably ancestral in songbirds, interspecific variations might all be variations on a single theme and need not be representative of the nature and characteristics of vocal learning in other bird groups. To assess the possible mechanisms of vocal learning and its evolution therefore requires knowledge about independently evolved incidences of vocal learning. This review examines the presence and nature of vocal production learning in non-songbirds. Using a broad definition of vocal learning and a comparative phylogenetic framework, I evaluate the evidence for vocal learning and its characteristics in non-oscine birds, including well-known vocal learners such as parrots and hummingbirds but also (putative) cases from other taxa. Despite the sometimes limited evidence, it is clear that vocal learning occurs in a range of different, non-related, taxa and can be caused by a variety of mechanisms. It is more widespread than often realized, calling for more systematic studies. Examining this variation may provide a window onto the evolution of vocal learning and increase the value of comparative research for understanding vocal learning in humans. This article is part of the theme issue ‘Vocal learning in animals and humans’.


2021 ◽  
Author(s):  
Carlos A. Rodriguez-Saltos ◽  
Aditya Bhise ◽  
Prasanna Karur ◽  
Ramsha Nabihah Khan ◽  
Sumin Lee ◽  
...  

In songbirds, learning to sing is a highly social process that likely involves social reward. Here, we hypothesized that the degree to which a juvenile songbird learns a song depends on the degree to which it finds that song rewarding to hear during vocal development. We tested this hypothesis by measuring song preferences in young birds during song learning and then analyzing their adult songs. Song preferences were measured in an operant key-pressing assay. Juvenile male zebra finches (Taeniopygia guttata) had access to two keys, each of which was associated with a higher likelihood of playing the song of their father or that of another familiar adult ("neighbor"). To minimize the effects of exposure on learning, we implemented a reinforcement schedule that allowed us to detect preferences while balancing exposure to each song. On average, the juveniles significantly preferred the father's song early during song learning, before they were themselves singing. At around post-hatch day 60, their preference shifted to the neighbor's song. At the end of the song learning period, we recorded the juveniles' songs and compared them to the father's and the neighbor's song. All of the birds copied father's song. The accuracy with which the father's song was imitated was positively correlated with the peak strength of the preference for the father's song during the sensitive period. Our results show that preference for a social stimulus, in this case a vocalization, predicted social learning during development.


Author(s):  
Amanda Monte ◽  
Alexander F. Cerwenka ◽  
Bernhard Ruthensteiner ◽  
Manfred Gahr ◽  
Daniel N. Düring

AbstractVocal learning is a rare evolutionary trait that evolved independently in three avian clades: songbirds, parrots, and hummingbirds. Although the anatomy and mechanisms of sound production in songbirds are well understood, little is known about the hummingbird’s vocal anatomy. We use high-resolution micro-computed tomography (μCT) and microdissection to reveal the three-dimensional structure of the syrinx, the vocal organ of the black jacobin (Florisuga fusca), a phylogenetically basal hummingbird species. We identify three unique features of the black jacobin’s syrinx: (i) a shift in the position of the syrinx to the outside of the thoracic cavity and the related loss of the sterno-tracheal muscle, (ii) complex intrinsic musculature, oriented dorso-ventrally, and (iii) ossicles embedded in the medial vibratory membranes. Their syrinx morphology allows vibratory decoupling, precise control of complex acoustic parameters, and a large redundant acoustic space that may be key biomechanical factors facilitating the occurrence of vocal production learning.


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