Correction to ‘A cross-species framework to identify vocal learning abilities in mammals’

With colourful plumage, charismatic character and vocal learning abilities, parrots are one of the most striking and recognizable bird groups. Their attractiveness has drawn human attention for centuries, and members of the Psittaciformes order were, also, among the first avian species to be subject to cytogenetic studies which have contributed to understand their taxonomic and evolutionary relationships.We present here the karyological results collected by the study of thirteen parrot species new to karyology. These results are additionally supported by G banded preparations obtained in five species.The order Psittaciformes is an interesting example of a, typically, non migratory avian lineage with Gondwanaland origin, whose evolutionary radiation has been shaped by the Cenozoic geographic and climatic events that affected the land masses derived from the Gondwanaland continental split.We discuss the results of our studies, in conjunction with the previously compiled Psittaciformes cytogenetic data to delineate a picture of the chromosomal evolution of the order, concurrently with the biogeographic history of the lands in the southern Hemisphere.Considering the available data on parrot cytogenetics, a "standard parrot karyotype pattern" is proposed for evolutionary comparisons.Several biogeographic, and phylogenetically related "karyogram patterns" are also identified, and mechanisms of chromosome rearrangement that associate this patterns among them, and with the standard parrot karyotype pattern are proposed. These schemes on parrot chromosomal variation are discussed in relation to the general avian chromosome evolutionary theses proposed by cytogenetic and molecular genomic researchers.

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Operant control and call usage learning in African elephants

Philosophical Transactions of the Royal Society B Biological Sciences ◽

10.1098/rstb.2020.0254 ◽

2021 ◽

Vol 376 (1836) ◽

pp. 20200254

Author(s):

Angela S. Stoeger ◽

Anton Baotic

Keyword(s):

Low Frequency ◽

Vocal Learning ◽

Social Contexts ◽

Cognitive Mechanisms ◽

African Elephants ◽

Verbal Cues ◽

Learning Abilities ◽

Vocal Plasticity ◽

Call Usage ◽

Usage Learning

Elephants exhibit remarkable vocal plasticity, and case studies reveal that individuals of African savannah ( Loxodonta africana ) and Asian ( Elephas maximus ) elephants are capable of vocal production learning. Surprisingly, however, little is known about contextual learning (usage and comprehension learning) in elephant communication. Usage learning can be demonstrated by training animals to vocalize in an arbitrary (cue-triggered) context. Here we show that adult African savannah elephants ( n = 13) can vocalize in response to verbal cues, reliably producing social call types such as the low-frequency rumble, trumpets and snorts as well as atypical sounds using various mechanisms, thus displaying compound vocal control. We further show that rumbles emitted upon trainer cues differ significantly in structure from rumbles triggered by social contexts of the same individuals ( n = 6). Every form of social learning increases the complexity of a communication system. In elephants, we only poorly understand their vocal learning abilities and the underlying cognitive mechanisms. Among other research, this calls for controlled learning experiments in which the prerequisite is operant/volitional control of vocalizations. This article is part of the theme issue ‘Vocal learning in animals and humans’.

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Vocal plasticity in harbour seal pups

10.1101/2021.02.10.430617 ◽

2021 ◽

Author(s):

Laura Torres Borda ◽

Yannick Jadoul ◽

Heikki Rasilo ◽

Anna Salazar Casals ◽

Andrea Ravignani

Keyword(s):

Vocal Learning ◽

Low Noise ◽

Noise Condition ◽

Learning Abilities ◽

Noise Masking ◽

Vocal Plasticity ◽

Lombard Effect ◽

Harbour Seals ◽

Exposed Individual ◽

Filtered Noise

ABSTRACTVocal plasticity can occur in response to environmental and biological factors, including conspecifics’ vocalisations and noise. Pinnipeds are one of the few mammalian groups capable of vocal learning, and are therefore relevant to understanding the evolution of vocal plasticity in humans and other animals. Here, we investigate the vocal plasticity of harbour seals (Phoca vitulina), a species with vocal learning abilities attested in adulthood but not puppyhood. To zoom into early mammalian vocal development, we tested 1-3 weeks old seal pups. We tailored noise playbacks to this species and age to induce seal pups to shift their fundamental frequency (F0), rather than adapt call amplitude or temporal characteristics. We exposed individual pups to bandpass-filtered noise, which purposely spanned – and masked – their typical range of F0s, and simultaneously recorded pups’ spontaneous calls. Seals were able to modify their vocalisations quite unlike most mammals: They lowered their F0 in response to increased noise. This modulation was punctual and adapted to the particular noise condition. In addition, higher noise induced less dispersion around the mean F0, suggesting that pups may have been actively focusing their phonatory efforts to target lower frequencies. Noise masking did not seem to affect call amplitude. However, one seal showed two characteristics of the Lombard effect known for human speech in noise: significant increase in call amplitude and flattening of spectral tilt. Our relatively low noise levels may have favoured F0 shifts while inhibiting amplitude adjustments. This lowering of F0 is quite unusual, as other animals commonly display no F0 shift independently of noise amplitude. Our data represents a relatively rare case in mammalian neonates, and may have implications for the evolution of vocal plasticity across species, including humans.

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Differences in short-term vocal learning in parrots, a comparative study

Behaviour ◽

10.1163/1568539x-00003286 ◽

2015 ◽

Vol 152 (11) ◽

pp. 1433-1461 ◽

Cited By ~ 3

Author(s):

Solveig Walløe ◽

Heidi Thomsen ◽

Thorsten J. Balsby ◽

Torben Dabelsteen

Keyword(s):

Vocal Learning ◽

Call Rate ◽

Short Term ◽

Contact Call ◽

Learning Abilities ◽

Nymphicus Hollandicus ◽

Contact Calls ◽

Widespread Phenomenon ◽

Parrot Species ◽

Degree Of Similarity

Parrots are renowned for their vocal learning abilities. Yet only few parrot species have been investigated and empirically proven to possess vocal learning abilities. The aim of this study was to investigate if short-term vocal learning may be a widespread phenomenon among Psittaciformes. Through an interactive experiment we compare the ability of four parrot species, the peach-fronted conure (Aratinga aurea), the cockatiel (Nymphicus hollandicus), the peach-faced lovebird (Agapornis roseicollis) and the budgerigar (Melopsittacus undulatus), to vocally match playback of contact calls. All four species made an overall change to their contact call in response to the playback, and they also varied the degree of similarity with the playback call throughout the playback experiment. The peach-fronted conure showed the biggest overall changes to their contact calls by vocally matching the playback call and the budgerigar showed the least change. The cockatiel and the peach-faced lovebird showed intermediary levels of change making their calls overall less similar to the playback call. The peach-fronted conure responded with highest similarity to familiar individuals and the cockatiel responded with an overall higher similarity to female playback stimuli. Cockatiel males and budgerigar males responded with a higher call rate to playback than female conspecifics. Peach-faced lovebirds responded fastest to unfamiliar males. Based on the results we conclude that short-term vocal learning is a widespread phenomenon among parrots. The way short-term vocal learning is used however, differs between species suggesting that short-term vocal learning have different functions in different species.

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Polly Wants a Genome: The Lack of Genetic Testing for Pet Parrot Species

Genes ◽

10.3390/genes12071097 ◽

2021 ◽

Vol 12 (7) ◽

pp. 1097

Author(s):

Henriëtte van der Zwan ◽

Rencia van der Sluis

Keyword(s):

Molecular Genetic ◽

Vocal Learning ◽

The United States ◽

Breeding Systems ◽

Future Research ◽

Plumage Colour ◽

Learning Abilities ◽

A Genome ◽

Close Relatives ◽

Genotype Screening

Parrots are considered the third most popular pet species, after dogs and cats, in the United States of America. Popular birds include budgerigars, lovebirds and cockatiels and are known for their plumage and vocal learning abilities. Plumage colour variation remains the main driving force behind breeder selection. Despite the birds’ popularity, only two molecular genetic tests—bird sexing and pathogen screening—are commercially available to breeders. For a limited number of species, parentage verification tests are available, but are mainly used in conservation and not for breeding purposes. No plumage colour genotyping test is available for any of the species. Due to the fact that there isn’t any commercial plumage genotype screening or parentage verification tests available, breeders mate close relatives to ensure recessive colour alleles are passed to the next generation. This, in turn, leads to inbreeding depression and decreased fertility, lower hatchability and smaller clutch sizes, all important traits in commercial breeding systems. This review highlights the research carried out in the field of pet parrot genomics and points out the areas where future research can make a vital contribution to understanding how parrot breeding can be improved to breed healthy, genetically diverse birds.

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Prenatal learning in an Australian songbird: habituation and individual discrimination in superb fairy-wren embryos

Proceedings of The Royal Society B Biological Sciences ◽

10.1098/rspb.2014.1154 ◽

2014 ◽

Vol 281 (1797) ◽

pp. 20141154 ◽

Cited By ~ 34

Author(s):

Diane Colombelli-Négrel ◽

Mark E. Hauber ◽

Sonia Kleindorfer

Keyword(s):

Heart Rate ◽

Heart Rate Response ◽

Vocal Learning ◽

Human Embryos ◽

Learning Abilities ◽

Parental Feeding ◽

Individual Discrimination ◽

Prenatal Learning ◽

In The Wild ◽

Malurus Cyaneus

Embryos were traditionally considered to possess limited learning abilities because of the immaturity of their developing brains. By contrast, neonates from diverse species show behaviours dependent on prior embryonic experience. Stimulus discrimination is a key component of learning and has been shown by a handful of studies in non-human embryos. Superb fairy-wren embryos ( Malurus cyaneus ) learn a vocal password that has been taught to them by the attending female during incubation. The fairy-wren embryos use the learned element as their begging call after hatching to solicit more parental feeding. In this study, we test whether superb fairy-wren embryos have the capacity to discriminate between acoustical stimuli and whether they show non-associative learning. We measured embryonic heart rate response using a habituation/dishabituation paradigm with eggs sourced from nests in the wild. Fairy-wren embryos lowered their heart rate in response to the broadcasts of conspecific versus heterospecific calls, and in response to the calls of novel conspecific individuals. Thus, fairy-wrens join humans as vocal-learning species with known prenatal learning and individual discrimination.

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A cross-species framework to identify vocal learning abilities in mammals

Philosophical Transactions of the Royal Society B Biological Sciences ◽

10.1098/rstb.2020.0394 ◽

2021 ◽

Vol 377 (1841) ◽

Author(s):

Andrea Ravignani ◽

Maxime Garcia

Keyword(s):

Sexual Selection ◽

Social Impact ◽

Regression Line ◽

Vocal Learning ◽

Intermediate Step ◽

Learning Abilities ◽

Correlational Approach ◽

Potential Link ◽

Multiple Species ◽

Voice Modulation

Vocal production learning (VPL) is the experience-driven ability to produce novel vocal signals through imitation or modification of existing vocalizations. A parallel strand of research investigates acoustic allometry, namely how information about body size is conveyed by acoustic signals. Recently, we proposed that deviation from acoustic allometry principles as a result of sexual selection may have been an intermediate step towards the evolution of vocal learning abilities in mammals. Adopting a more hypothesis-neutral stance, here we perform phylogenetic regressions and other analyses further testing a potential link between VPL and being an allometric outlier. We find that multiple species belonging to VPL clades deviate from allometric scaling but in the opposite direction to that expected from size exaggeration mechanisms. In other words, our correlational approach finds an association between VPL and being an allometric outlier. However, the direction of this association, contra our original hypothesis, may indicate that VPL did not necessarily emerge via sexual selection for size exaggeration: VPL clades show higher vocalization frequencies than expected. In addition, our approach allows us to identify species with potential for VPL abilities: we hypothesize that those outliers from acoustic allometry lying above the regression line may be VPL species. Our results may help better understand the cross-species diversity, variability and aetiology of VPL, which among other things is a key underpinning of speech in our species. This article is part of the theme issue ‘Voice modulation: from origin and mechanism to social impact (Part II)’.

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Vocal plasticity in harbour seal pups

Philosophical Transactions of the Royal Society B Biological Sciences ◽

10.1098/rstb.2020.0456 ◽

2021 ◽

Vol 376 (1840) ◽

Cited By ~ 1

Author(s):

Laura Torres Borda ◽

Yannick Jadoul ◽

Heikki Rasilo ◽

Anna Salazar Casals ◽

Andrea Ravignani

Keyword(s):

Social Impact ◽

Vocal Learning ◽

Experimental Manipulation ◽

Low Noise ◽

Noise Condition ◽

Learning Abilities ◽

Vocal Plasticity ◽

Lombard Effect ◽

Exposed Individual ◽

Filtered Noise

Vocal plasticity can occur in response to environmental and biological factors, including conspecifics' vocalizations and noise. Pinnipeds are one of the few mammalian groups capable of vocal learning, and are therefore relevant to understanding the evolution of vocal plasticity in humans and other animals. Here, we investigate the vocal plasticity of harbour seals ( Phoca vitulina ), a species with vocal learning abilities observed in adulthood but not puppyhood. To evaluate early mammalian vocal development, we tested 1–3 weeks-old seal pups. We tailored noise playbacks to this species and age to induce seal pups to shift their fundamental frequency ( f 0 ), rather than adapt call amplitude or temporal characteristics. We exposed individual pups to low- and high-intensity bandpass-filtered noise, which spanned—and masked—their typical range of f 0 ; simultaneously, we recorded pups' spontaneous calls. Unlike most mammals, pups modified their vocalizations by lowering their f 0 in response to increased noise. This modulation was precise and adapted to the particular experimental manipulation of the noise condition. In addition, higher levels of noise induced less dispersion around the mean f 0 , suggesting that pups may have actively focused their phonatory efforts to target lower frequencies. Noise did not seem to affect call amplitude. However, one seal showed two characteristics of the Lombard effect known for human speech in noise: significant increase in call amplitude and flattening of spectral tilt. Our relatively low noise levels may have favoured f 0 modulation while inhibiting amplitude adjustments. This lowering of f 0 is unusual, as most animals commonly display no such f 0 shift. Our data represent a relatively rare case in mammalian neonates, and have implications for the evolution of vocal plasticity and vocal learning across species, including humans. This article is part of the theme issue ‘Voice modulation: from origin and mechanism to social impact (Part I)’.

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