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Kaplan G. The evolution of social play in songbirds, parrots and cockatoos - emotional or highly complex cognitive behaviour or both? Neurosci Biobehav Rev 2024; 161:105621. [PMID: 38479604 DOI: 10.1016/j.neubiorev.2024.105621] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2023] [Revised: 02/04/2024] [Accepted: 03/09/2024] [Indexed: 04/20/2024]
Abstract
Social play has been described in many animals. However, much of this social behaviour among birds, particularly in adults, is still relatively unexplored in terms of the environmental, psychological, and social dynamics of play. This paper provides an overview of what we know about adult social play in birds and addresses areas in which subtleties and distinctions, such as in play initiation and social organisation and its relationship to expressions of play, are considered in detail. The paper considers emotional, social, innovative, and cognitive aspects of play, then the environmental conditions and affiliative bonds, suggesting a surprisingly complex framework of criteria awaiting further research. Adult social play has so far been studied in only a small number of avian species, exclusively in those with a particularly large brain relative to body size without necessarily addressing brain functions and lateralization. When lateralization of brain function is considered, it can further illuminate a possibly significant relevance of play behaviour to the evolution of cognition, to management of emotions, and the development of sociality.
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Affiliation(s)
- Gisela Kaplan
- University of New England, Armidale, NSW, Australia.
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Erb WM, Ross W, Kazanecki H, Mitra Setia T, Madhusudhana S, Clink DJ. Vocal complexity in the long calls of Bornean orangutans. PeerJ 2024; 12:e17320. [PMID: 38766489 PMCID: PMC11100477 DOI: 10.7717/peerj.17320] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2023] [Accepted: 04/09/2024] [Indexed: 05/22/2024] Open
Abstract
Vocal complexity is central to many evolutionary hypotheses about animal communication. Yet, quantifying and comparing complexity remains a challenge, particularly when vocal types are highly graded. Male Bornean orangutans (Pongo pygmaeus wurmbii) produce complex and variable "long call" vocalizations comprising multiple sound types that vary within and among individuals. Previous studies described six distinct call (or pulse) types within these complex vocalizations, but none quantified their discreteness or the ability of human observers to reliably classify them. We studied the long calls of 13 individuals to: (1) evaluate and quantify the reliability of audio-visual classification by three well-trained observers, (2) distinguish among call types using supervised classification and unsupervised clustering, and (3) compare the performance of different feature sets. Using 46 acoustic features, we used machine learning (i.e., support vector machines, affinity propagation, and fuzzy c-means) to identify call types and assess their discreteness. We additionally used Uniform Manifold Approximation and Projection (UMAP) to visualize the separation of pulses using both extracted features and spectrogram representations. Supervised approaches showed low inter-observer reliability and poor classification accuracy, indicating that pulse types were not discrete. We propose an updated pulse classification approach that is highly reproducible across observers and exhibits strong classification accuracy using support vector machines. Although the low number of call types suggests long calls are fairly simple, the continuous gradation of sounds seems to greatly boost the complexity of this system. This work responds to calls for more quantitative research to define call types and quantify gradedness in animal vocal systems and highlights the need for a more comprehensive framework for studying vocal complexity vis-à-vis graded repertoires.
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Affiliation(s)
- Wendy M. Erb
- K. Lisa Yang Center for Conservation Bioacoustics, Cornell Lab of Ornithology, Cornell University, Ithaca, NY, United States of America
- Department of Anthropology, Rutgers, The State University of New Jersey, New Brunswick, United States of America
| | - Whitney Ross
- K. Lisa Yang Center for Conservation Bioacoustics, Cornell Lab of Ornithology, Cornell University, Ithaca, NY, United States of America
| | - Haley Kazanecki
- K. Lisa Yang Center for Conservation Bioacoustics, Cornell Lab of Ornithology, Cornell University, Ithaca, NY, United States of America
| | - Tatang Mitra Setia
- Primate Research Center, Universitas Nasional Jakarta, Jakarta, Indonesia
- Department of Biology, Faculty of Biology and Agriculture, Universitas Nasional Jakarta, Jakarta, Indonesia
| | - Shyam Madhusudhana
- K. Lisa Yang Center for Conservation Bioacoustics, Cornell Lab of Ornithology, Cornell University, Ithaca, NY, United States of America
- Centre for Marine Science and Technology, Curtin University, Perth, Australia
| | - Dena J. Clink
- K. Lisa Yang Center for Conservation Bioacoustics, Cornell Lab of Ornithology, Cornell University, Ithaca, NY, United States of America
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Nelson XJ, Taylor AH, Cartmill EA, Lyn H, Robinson LM, Janik V, Allen C. Joyful by nature: approaches to investigate the evolution and function of joy in non-human animals. Biol Rev Camb Philos Soc 2023; 98:1548-1563. [PMID: 37127535 DOI: 10.1111/brv.12965] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2022] [Revised: 04/12/2023] [Accepted: 04/17/2023] [Indexed: 05/03/2023]
Abstract
The nature and evolution of positive emotion is a major question remaining unanswered in science and philosophy. The study of feelings and emotions in humans and animals is dominated by discussion of affective states that have negative valence. Given the clinical and social significance of negative affect, such as depression, it is unsurprising that these emotions have received more attention from scientists. Compared to negative emotions, such as fear that leads to fleeing or avoidance, positive emotions are less likely to result in specific, identifiable, behaviours being expressed by an animal. This makes it particularly challenging to quantify and study positive affect. However, bursts of intense positive emotion (joy) are more likely to be accompanied by externally visible markers, like vocalisations or movement patterns, which make it more amenable to scientific study and more resilient to concerns about anthropomorphism. We define joy as intense, brief, and event-driven (i.e. a response to something), which permits investigation into how animals react to a variety of situations that would provoke joy in humans. This means that behavioural correlates of joy are measurable, either through newly discovered 'laughter' vocalisations, increases in play behaviour, or reactions to cognitive bias tests that can be used across species. There are a range of potential situations that cause joy in humans that have not been studied in other animals, such as whether animals feel joy on sunny days, when they accomplish a difficult feat, or when they are reunited with a familiar companion after a prolonged absence. Observations of species-specific calls and play behaviour can be combined with biometric markers and reactions to ambiguous stimuli in order to enable comparisons of affect between phylogenetically distant taxonomic groups. Identifying positive affect is also important for animal welfare because knowledge of positive emotional states would allow us to monitor animal well-being better. Additionally, measuring if phylogenetically and ecologically distant animals play more, laugh more, or act more optimistically after certain kinds of experiences will also provide insight into the mechanisms underlying the evolution of joy and other positive emotions, and potentially even into the evolution of consciousness.
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Affiliation(s)
- Ximena J Nelson
- Private Bag 4800, School of Biological Sciences, University of Canterbury, Christchurch, New Zealand
| | - Alex H Taylor
- Institut de Neurociències, Universitat Autònoma de Barcelona, Bellaterra, Barcelona, 08193, Spain
- ICREA, Pg. Lluís Companys, 23, Barcelona, Spain
- School of Psychology, The University of Auckland, Private Bag 92019, Auckland, 1142, New Zealand
| | - Erica A Cartmill
- Departments of Anthropology and Psychology, UCLA, 375 Portola Plaza, Los Angeles, CA, 90095, USA
| | - Heidi Lyn
- Department of Psychology, University of South Alabama, 75 S. University Blvd., Mobile, AL, 36688, USA
| | - Lauren M Robinson
- Domestication Lab, Konrad Lorenz Institute of Ethology, University of Veterinary Medicine, Vienna, Savoyenstraße 1a, Vienna, A-1160, Austria
| | - Vincent Janik
- Scottish Oceans Institute, School of Biology, University of St. Andrews, St Andrews, KY16 8LB, UK
| | - Colin Allen
- Department of History & Philosophy of Science, University of Pittsburgh, 1101 Cathedral of Learning, 4200 Fifth Ave, Pittsburgh, PA, 15260, USA
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Bastos APM, Nelson XJ, Taylor AH. From the lab to the wild: how can captive studies aid the conservation of kea (Nestor notabilis)? Curr Opin Behav Sci 2022. [DOI: 10.1016/j.cobeha.2022.101131] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Romani F, Ramella Levis E, Posillico M, Opramolla G, Pavan G. Vocal repertoire of the Eurasian griffon vulture ( Gyps fulvus) in the central Apennines: a baseline assessment. BIOACOUSTICS 2021. [DOI: 10.1080/09524622.2021.1925591] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Affiliation(s)
- Federico Romani
- Centro Interdisciplinare di Bioacustica e Ricerche Ambientali, Department of Earth and Environment Sciences, University of Pavia, Pavia, Italy
- Eurafrica Conservation Projects, Non-Profit Organization for the Conservation of Biodiversity, Rome, Italy
| | - Elena Ramella Levis
- Centro Interdisciplinare di Bioacustica e Ricerche Ambientali, Department of Earth and Environment Sciences, University of Pavia, Pavia, Italy
- Eurafrica Conservation Projects, Non-Profit Organization for the Conservation of Biodiversity, Rome, Italy
| | - Mario Posillico
- Reparto Carabinieri Biodiversità, Centro Ricerche Ambienti Montani, Castel di Sangro (AQ), Italy
| | - Giancarlo Opramolla
- Reparto Carabinieri Biodiversità, Centro Ricerche Ambienti Montani, Castel di Sangro (AQ), Italy
| | - Gianni Pavan
- Centro Interdisciplinare di Bioacustica e Ricerche Ambientali, Department of Earth and Environment Sciences, University of Pavia, Pavia, Italy
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Austin VI, Dalziell AH, Langmore NE, Welbergen JA. Avian vocalisations: the female perspective. Biol Rev Camb Philos Soc 2021; 96:1484-1503. [PMID: 33797176 DOI: 10.1111/brv.12713] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2020] [Revised: 03/16/2021] [Accepted: 03/17/2021] [Indexed: 01/04/2023]
Abstract
Research on avian vocalisations has traditionally focused on male song produced by oscine passerines. However, accumulating evidence indicates that complex vocalisations can readily evolve outside the traditional contexts of mate attraction and territory defence by male birds, and yet the previous bias towards male song has shaped - and continues to shape - our understanding of avian communication as a whole. Accordingly, in this review we seek to address this imbalance by synthesising studies on female vocalisations from across signalling contexts throughout the Aves, and discuss the implications of recent empirical advances for our understanding of vocalisations in both sexes. This review reveals great structural and functional diversity among female vocalisations and highlights the important roles that vocalisations can play in mediating female-specific behaviours. However, fundamental gaps remain. While there are now several case studies that identify the function of female vocalisations, few quantify the associated fitness benefits. Additionally, very little is known about the role of vocal learning in the development of female vocalisations. Thus, there remains a pressing need to examine the function and development of all forms of vocalisations in female birds. In the light of what we now know about the functions and mechanisms of female vocalisations, we suggest that conventional male-biased definitions of songs and calls are inadequate for furthering our understanding of avian vocal communication more generally. Therefore, we propose two simple alternatives, both emancipated from the sex of the singer. The first distinguishes song from calls functionally as a sexually selected vocal signal, whilst the second distinguishes them mechanistically in terms of their underlying neurological processes. It is clear that more investigations are needed into the ultimate and proximate causes of female vocalisations; however, these are essential if we are to develop a holistic epistemology of avian vocal communication in both sexes, across ecological contexts and taxonomic divides.
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Affiliation(s)
- Victoria I Austin
- Hawkesbury Institute for the Environment, Western Sydney University, Hawkesbury Campus, Ground Floor, Building R2, Locked Bag 1797, Penrith, NSW, 2751, Australia
| | - Anastasia H Dalziell
- Hawkesbury Institute for the Environment, Western Sydney University, Hawkesbury Campus, Ground Floor, Building R2, Locked Bag 1797, Penrith, NSW, 2751, Australia.,Centre for Sustainable Ecosystem Solutions, School of Earth, Atmospheric and Life Sciences, University of Wollongong, Northfields Ave, Wollongong, NSW, 2522, Australia.,Cornell Lab of Ornithology, Cornell University, 159 Sapsucker Woods Rd., Ithaca, NY, 14850, U.S.A
| | - Naomi E Langmore
- Research School of Biology, The Australian National University, 46 Sullivan's Creek Road, Acton, Canberra, ACT, 2601, Australia
| | - Justin A Welbergen
- Hawkesbury Institute for the Environment, Western Sydney University, Hawkesbury Campus, Ground Floor, Building R2, Locked Bag 1797, Penrith, NSW, 2751, Australia
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Roubalová T, Giret N, Bovet D, Policht R, Lindová J. Shared calls in repertoires of two locally distant gray parrots (Psittacus erithacus). Acta Ethol 2020. [DOI: 10.1007/s10211-020-00350-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Bertin A, Beraud A, Lansade L, Mulot B, Arnould C. Bill covering and nape feather ruffling as indicators of calm states in the Sulphur-crested cockatoo (Cacatua galerita). Behav Processes 2020; 178:104188. [PMID: 32598901 DOI: 10.1016/j.beproc.2020.104188] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2020] [Revised: 06/19/2020] [Accepted: 06/25/2020] [Indexed: 01/28/2023]
Abstract
Parrots are highly social birds that are recognized for their primate-like cognitive abilities but their way to express emotions remain overlooked. Herein we explored potential facial indicators of emotions in cockatoos. We predicted that facial feather ruffling is an indicator of a cockatoo's emotional state and hypothesized that specific facial feather positions would be present more during positive valence and low arousal situations. We observed feather position on the crest, cheek and nape during the daily routine of a group of five captive, non-breeding, Sulphur-crested cockatoos. The data show that cheek and nape feather ruffling occurred significantly more during activities associated with low arousal levels and positive valence such as maintenance behaviours, positive and quiet social contact and resting. Our data suggest that ruffling feathers over the bill (i.e. cheek feather ruffling) and nape ruffling may provide visual indicators of calm/relaxed states in cockatoos. Subtle movement of facial feathers may be an effective close-ranged visual signal to communicate birds' affective states or their intention to engage in specific activities. This work provides a novel approach to assessing the positive welfare of captive cockatoos and to understanding emotional communication in non-mammalian species.
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Affiliation(s)
- Aline Bertin
- PRC, CNRS, IFCE, INRAE, Université de Tours, 37380, Nouzilly, France.
| | - Arielle Beraud
- PRC, CNRS, IFCE, INRAE, Université de Tours, 37380, Nouzilly, France; ZooParc de Beauval & Beauval Nature, Saint-Aignan, France.
| | - Léa Lansade
- PRC, CNRS, IFCE, INRAE, Université de Tours, 37380, Nouzilly, France.
| | - Baptiste Mulot
- ZooParc de Beauval & Beauval Nature, Saint-Aignan, France.
| | - Cécile Arnould
- PRC, CNRS, IFCE, INRAE, Université de Tours, 37380, Nouzilly, France.
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Khan AA, Qureshi IZ. High-level individuality in vocalizations of a well-known avian brood parasite: Asian koel ( Eudynamys scolopacea L.). BIOACOUSTICS 2020. [DOI: 10.1080/09524622.2020.1784281] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Affiliation(s)
- Abdul Aziz Khan
- Laboratory of Animal and Human Physiology, Department of Animal Sciences, Quaid-i-Azam University, Islamabad, Pakistan
| | - Irfan Zia Qureshi
- Laboratory of Animal and Human Physiology, Department of Animal Sciences, Quaid-i-Azam University, Islamabad, Pakistan
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Wein A, Schwing R, Yanagida T, Huber L. Vocal development in nestling kea parrots ( Nestor notabilis). BIOACOUSTICS 2020. [DOI: 10.1080/09524622.2019.1705184] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Affiliation(s)
- Amelia Wein
- Comparative Cognition, Messerli Research Institute, University of Veterinary Medicine Vienna, Medical University of Vienna, University of Vienna, Vienna, Austria
| | - Raoul Schwing
- Comparative Cognition, Messerli Research Institute, University of Veterinary Medicine Vienna, Medical University of Vienna, University of Vienna, Vienna, Austria
| | - Takuya Yanagida
- Department of Applied Psychology: Work, Education, and Economy, Faculty of Psychology, University of Vienna, Vienna, Austria
| | - Ludwig Huber
- Comparative Cognition, Messerli Research Institute, University of Veterinary Medicine Vienna, Medical University of Vienna, University of Vienna, Vienna, Austria
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Schwing R, Nelson XJ, Wein A, Parsons S. Positive emotional contagion in a New Zealand parrot. Curr Biol 2018; 27:R213-R214. [PMID: 28324733 DOI: 10.1016/j.cub.2017.02.020] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
Positive emotional contagions are outwardly emotive actions that spread from one individual to another, such as glee in preschool children [1] or laughter in humans of all ages [2]. The play vocalizations of some animals may also act as emotional contagions. For example, artificially deafened rats are less likely to play than their non-hearing-impaired conspecifics, while no such effect is found for blinded rats [3]. As rat play vocalizations are also produced in anticipation of play, they, rather than the play itself, may act as a contagion, leading to a hypothesis of evolutionary parallels between rat play vocalizations and human laughter [4]. The kea parrot (Nestor notabilis) has complex play behaviour and a distinct play vocalization [5]. We used acoustic playback to investigate the effect of play calls on wild kea, finding that play vocalizations increase the amount of play among both juveniles and adults, likely by acting as a positive emotional contagion.
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Affiliation(s)
- Raoul Schwing
- Comparative Cognition, Messerli Research Institute, University of Veterinary Medicine Vienna, Medical University of Vienna, University of Vienna, Vienna, Austria; Haidlhof Research Station, University of Veterinary Medicine Vienna and University of Vienna, Bad Vöslau, Austria; School of Biological Sciences, University of Auckland, Auckland, New Zealand.
| | - Ximena J Nelson
- School of Biological Sciences, University of Canterbury, Christchurch, New Zealand
| | - Amelia Wein
- Comparative Cognition, Messerli Research Institute, University of Veterinary Medicine Vienna, Medical University of Vienna, University of Vienna, Vienna, Austria; Haidlhof Research Station, University of Veterinary Medicine Vienna and University of Vienna, Bad Vöslau, Austria
| | - Stuart Parsons
- School of Biological Sciences, University of Auckland, Auckland, New Zealand; School of Earth, Environmental and Biological Sciences, Queensland University of Technology, Brisbane, Australia
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Socially-mediated arousal and contagion within domestic chick broods. Sci Rep 2018; 8:10509. [PMID: 30002482 PMCID: PMC6043517 DOI: 10.1038/s41598-018-28923-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2018] [Accepted: 07/03/2018] [Indexed: 12/13/2022] Open
Abstract
Emotional contagion - an underpinning valenced feature of empathy - is made up of simpler, potentially dissociable social processes which can include socially-mediated arousal and behavioural/physiological contagion. Previous studies of emotional contagion have often conflated these processes rather than examining their independent contribution to empathic response. We measured socially-mediated arousal and contagion in 9-week old domestic chicks (n = 19 broods), who were unrelated but raised together from hatching. Pairs of observer chicks were exposed to two conditions in a counterbalanced order: air puff to conspecifics (AP) (during which an air puff was applied to three conspecifics at 30 s intervals) and control with noise of air puff (C) (during which the air puff was directed away from the apparatus at 30 s intervals). Behaviour and surface eye temperature of subjects and observers were measured throughout a 10-min pre-treatment and 10-min treatment period. Subjects and observers responded to AP with increased freezing, and reduced preening and ground pecking. Subjects and observers also showed reduced surface eye temperature - indicative of stress-induced hyperthermia. Subject-Observer behaviour was highly correlated within broods during both C and AP conditions, but with higher overall synchrony during AP. We demonstrate the co-occurrence of socially-mediated behavioural and physiological arousal and contagion; component features of emotional contagion.
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Schwing R, Nelson XJ, Parsons S. Audiogram of the kea parrot, Nestor notabilis. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2016; 140:3739. [PMID: 27908073 DOI: 10.1121/1.4967757] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Vocal communication requires the sender to produce a sound, which transmits through the environment and is perceived by the receiver. Perception is dependent on the quality of the received signal and the receiver's frequency and amplitude sensitivity; hearing sensitivity of animals can be tested using behavioural detection tasks, showing the physical limitations of sound perception. Kea parrots (Nestor notabilis) were tested for their ability to hear sounds that varied in terms of both frequency and amplitude by means of a simple auditory detection task. Audiograms for three kea were similar, with the region of highest sensitivity (1-5 kHz) corresponding to the frequency of the highest amplitude in kea calls. Compared with other parrots and other bird taxa, the overall shape of the kea audiogram follows a similar pattern. However, two potentially interesting differences to the audiograms of other birds were found: an increase in sensitivity at approximately 12 kHz and a decreased sensitivity to frequencies below 1 kHz.
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Affiliation(s)
- Raoul Schwing
- Comparative Cognition, Messerli Research Institute, University of Veterinary Medicine Vienna, Medical University of Vienna, University of Vienna, Veterinärplatz 1, 1210 Vienna, Austria
| | - Ximena J Nelson
- School of Biological Sciences, University of Canterbury, Private Bag 4800, Christchurch 8140, New Zealand
| | - Stuart Parsons
- School of Biological Sciences, The University of Auckland, Private Bag 92019, Auckland Mail Centre, Auckland 1142, New Zealand
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Montes-Medina AC, Salinas-Melgoza A, Renton K. Contextual flexibility in the vocal repertoire of an Amazon parrot. Front Zool 2016; 13:40. [PMID: 27570534 PMCID: PMC5000441 DOI: 10.1186/s12983-016-0169-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2016] [Accepted: 08/08/2016] [Indexed: 11/28/2022] Open
Abstract
Background Understanding the role of avian vocal communication in social organisation requires knowledge of the vocal repertoire used to convey information. Parrots use acoustic signals in a variety of social contexts, but no studies have evaluated cross-functional use of acoustic signals by parrots, or whether these conform to signal design rules for different behavioural contexts. We statistically characterised the vocal repertoire of 61 free-living Lilac-crowned Amazons (Amazona finschi) in nine behavioural contexts (nesting, threat, alarm, foraging, perched, take-off, flight, landing, and food soliciting). We aimed to determine whether parrots demonstrated contextual flexibility in their vocal repertoire, and whether these acoustic signals follow design rules that could maximise communication. Results The Lilac-crowned Amazon had a diverse vocal repertoire of 101 note-types emitted at least twice, 58 of which were emitted ≥5 times. Threat and nesting contexts had the greatest variety and proportion of exclusive note-types, although the most common note-types were emitted in all behavioural contexts but with differing proportional contribution. Behavioural context significantly explained variation in acoustic features, where threat and nesting contexts had the highest mean frequencies and broad bandwidths, and alarm signals had a high emission rate of 3.6 notes/s. Three Principal Components explained 72.03 % of the variation in temporal and spectral characteristics of notes. Permutated Discriminant Function Analysis using these Principal Components demonstrated that 28 note-types (emitted by >1 individual) could be correctly classified and significantly discriminated from a random model. Conclusions Acoustic features of Lilac-crowned Amazon vocalisations in specific behavioural contexts conformed to signal design rules. Lilac-crowned Amazons modified the emission rate and proportional contribution of note-types used in each context, suggesting the use of graded and combinatorial variation to encode information. We propose that evaluation of vocal repertoires based on note-types would reflect the true extent of a species’ vocal flexibility, and the potential for combinatorial structures in parrot acoustic signals. Electronic supplementary material The online version of this article (doi:10.1186/s12983-016-0169-6) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Adolfo Christian Montes-Medina
- Posgrado en Ciencias Biológicas, Instituto de Biología, Universidad Nacional Autónoma de México, Ciudad Universitaria, Mexico City, Mexico
| | - Alejandro Salinas-Melgoza
- Facultad de Biología, Universidad Michoacana de San Nicolás de Hidalgo, Ciudad Universitaria, Morelia, Michoacán Mexico
| | - Katherine Renton
- Estación de Biología Chamela, Instituto de Biología, Universidad Nacional Autónoma de México, Apartado Postal 21, San Patricio-Melaque, Chamela, Jalisco CP 48980 Mexico
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Affiliation(s)
- Amelia Wein
- Messerli Research Institute; University of Veterinary Medicine Vienna; Medical University Vienna; University of Vienna; Vienna Austria
- Cognitive Science; Department of Philosophy; Faculty of Philosophy and Education; University of Vienna; Vienna Austria
| | - Gyula K. Gajdon
- Messerli Research Institute; University of Veterinary Medicine Vienna; Medical University Vienna; University of Vienna; Vienna Austria
| | - Raoul Schwing
- Messerli Research Institute; University of Veterinary Medicine Vienna; Medical University Vienna; University of Vienna; Vienna Austria
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