@article {53511, title = {Body size and vocalization in primates and carnivores}, journal = {Scientific Reports}, volume = {7}, year = {2017}, month = {Jan-12-2017}, abstract = {

A fundamental assumption in bioacoustics is that large animals tend to produce vocalizations with lower frequencies than small animals. This inverse relationship between body size and vocalization frequencies is widely considered to be foundational in animal communication, with prominent theories arguing that it played a critical role in the evolution of vocal communication, in both production and perception. A major shortcoming of these theories is that they lack a solid empirical foundation: rigorous comparisons between body size and vocalization frequencies remain scarce, particularly among mammals. We address this issue here in a study of body size and vocalization frequencies conducted across 91 mammalian species, covering most of the size range in the orders Primates (n\ =\ 50; ~0.11\–120\ Kg) and Carnivora (n\ =\ 41; ~0.14\–250\ Kg). We employed a novel procedure designed to capture spectral variability and standardize frequency measurement of vocalization data across species. The results unequivocally demonstrate strong inverse relationships between body size and vocalization frequencies in primates and carnivores, filling a long-standing gap in mammalian bioacoustics and providing an empirical foundation for theories on the adaptive function of call frequency in animal communication.

}, doi = {10.1038/srep41070}, url = {http://www.nature.com/articles/srep41070}, author = {Bowling, D. L. and M. Garcia and Dunn, J. C. and Ruprecht, R. and Stewart, A. and Frommolt, K.-H. and Fitch, W. T.} } @article {52598, title = {Environmental factors could constrain the use of long-range vocal signals in solitary tuco-tucos (Ctenomys; Rodentia, Ctenomyidae) reproduction }, journal = {Journal of Ecoacoustics}, volume = {1}, year = {2017}, month = {Oct-24-20172112}, pages = {R7YFP0}, abstract = {

Ctenomys are mainly solitary subterranean rodents. Life underground has advantages (protection against predators, environmental control and reduced competition) but also implies disadvantages (digging costs, coping with hypercapnia, physiological and sensory changes, and communication problems) that can affect the social structure. Reproduction is a critical moment in the use of the signal repertoire, because individuals should locate in space, travel to, contact and copulate with a suitable partner. Energy expenditure involved in digging (connecting) tunnels makes difficult to attain a partner burrow system, but predation risk involved in moving above ground can counterbalance it and coupled with the spatial structure of the population, can determine the best communicative strategy to contact and locate a potential partner. Vocalisations allow to communicate over longer distances an with a reduced risk, while chemical signals, mostly aimed at vomerolfaction involve proximity or direct contact with the sample odour thus making information gathering more risky. As Ctenomys can use different signal types to gather different types of information leading to copulation, we propose that the use of these signals would be flexible, depending mostly on population spatial structure and type of predators living in the zone. This is because differences among species and/or populations in the use and characteristics of long-range vocalisations could be induced by environmental and/or social factors. This variation could be considered as a case of phenotypic plasticity, determining communication strategies variability in reproductive context, mostly dependent on long-range communication signals and the behaviour of males.

}, doi = {10.22261/JEA10.22261/JEA.R7YFP0}, author = {Francescoli, Gabriel} } @article {52578, title = {Silent porpoise: potential sleeping behaviour identified in wild harbour porpoises}, journal = {Animal Behaviour}, volume = {133}, year = {2017}, month = {Jan-11-2017}, pages = {211 - 222}, abstract = {

All animals sleep and it is essential for maintaining optimal brain function. However, cetaceans engage in the unusual practice of unihemispherical sleep, where only half of their brain sleeps at a time, due to their constant need for movement and breathing. Most studies of sleep in cetaceans have occurred in captivity. However, tagging devices have now developed to the point where the data collected from wild animals can be assessed against published criteria for defining sleep behaviourally. Seven acoustic and behavioural data loggers were deployed on harbour porpoises, Phocoena phocoena, in Danish waters between May 2010 and August 2011 and stayed on the animals between 53 and 72 h, recording 1884 to 2755 valid dives per animal. Parabolic dives with significantly reduced bioacoustic activity and a ste- reotyped behavioural pattern were identified as potential sleeping periods. The recordings for nearly half of the parabolic dives were found to contain no vocalization (echolocation clicks), significantly more than other dive types. Of the remaining parabolic dives, the click rate was, when normalized to their indi- vidual means, also significantly lower than detected in other dive types. Additionally, parabolic dives were shallow compared to all other dive types, and found to have a stereotypic low-energy profile. They were also found to contain fewer rolls and incorporate a lower vertical descent rate than most other dive types. If the data are representative, harbour porpoises spend a small, but meaningful amount of their diving time engaged in parabolic dives and thus potentially sleeping. All animals have a fundamental need for undisturbed sleep. These quiet periods thus need to be considered in studies of anthropogenic effects, but also those employing passive acoustic monitoring techniques, as well as in efforts to reduce incidental bycatch in fisheries, given the associated periods of reduced environmental awareness.

}, keywords = {A-tag, acoustic tags, data storage, e Phocoena, echolocation, harbour porpois, satellite telemetry, sleeping behaviour, tags}, issn = {00033472}, doi = {10.1016/j.anbehav.2017.09.015}, url = {http://linkinghub.elsevier.com/retrieve/pii/S0003347217303020}, author = {Wright, Andrew J. and Akamatsu, Tomonari and Mouritsen, Kim N. and Sveegaard, Signe and Dietz, Rune and Teilmann, Jonas} } @article {52576, title = {Male hyraxes increase countersinging as strangers become {\textquoteleft}nasty neighbours{\textquoteright}}, journal = {Animal Behaviour}, volume = {134}, year = {2017}, month = {Jan-12-2017}, pages = {9 - 14}, abstract = {

Many territorial animals interact less aggressively with neighbours than with strangers, a phenomenon known as the \‘dear enemy\’ effect, although some species show the opposite behaviour. Rock hyraxes, Procavia capensis, are social mammals that communicate via a rich acoustic repertoire. Male hyraxes produce elaborate advertisement calls (i.e. songs) both spontaneously and in response to occasional attention-grabbing events (e.g. pup screams, agonistic interaction), as well as to conspecific male songs. When replying to conspecific songs, male hyraxes tend to respond more to familiar males than to strangers, reflecting the \‘nasty neighbour\’ effect. Our study relates to the general question of why some species respond aggressively towards neighbours, while others are more aggressive towards strangers. We hypothesized that male hyraxes eventually familiarize themselves with a stranger, subsequently perceiving its intentions as highly threatening and deserving of a vocal response. To simulate the presence of a stranger in the area we exposed wild hyrax groups to playbacks of natural songs of un- familiar hyraxes. Male rock hyraxes became more likely to reply to a stranger\&$\#$39;s song over time, but this was independent of the number of times they heard the song. This suggests that either (1) the threat presented by a stranger increases when it is no longer perceived as transient or (2) because listeners do not physically encounter the stranger, they perceive replying aggressively as a low-risk response. Our work implies that species may demonstrate a range of condition-dependent behaviours instead of a dichotomy between the \‘nasty neighbour\’ and \‘dear enemy\’ strategies.

}, keywords = {advertisement, animal communication, floating territory, neighbour-stranger relationships, social mammals, vocalization}, issn = {00033472}, doi = {10.1016/j.anbehav.2017.10.002}, url = {http://linkinghub.elsevier.com/retrieve/pii/S000334721730324X}, author = {Goll, Yael and Demartsev, Vlad and Koren, Lee and Geffen, Eli} } @article {52573, title = {Call concatenation in wild meerkats}, journal = {Animal Behaviour}, volume = {134}, year = {2017}, month = {Jan-12-2017}, pages = {257 - 269}, abstract = {

Repertoire size, frequently determined by the number of discrete call types, has been used to assess vocal complexity in animals. However, species can also increase their communicative complexity by using graded signals or by combining individual calls. Animal call sequences can be divided into two main categories, each subdivided into two classes: repetitions, with either an unlimited or finite number of iterations of the same call type, and mixed call combinations, composed of two or more graded or discrete call types. Social contexts involve a wide range of behaviours and, unlike predation contexts, can be associated with both positive and negative emotions. Therefore, interactions linked to social contexts may place additional demands on an animal\&$\#$39;s communicative system and lead to the use of call com- binations. We systematically documented call combinations produced by wild meerkats, Suricata sur- icatta, a highly social carnivore, in social contexts in their natural habitat. We observed 12 distinct call combinations belonging to all four classes of combination, produced in all the observed behavioural contexts. Four combinations were each produced in a specific context whereas the remaining eight were produced in several contexts, albeit in different proportions. The broad use of combinations suggests that they represent a non-negligible part of meerkat social communication and that they can be used in flexible ways across various behavioural contexts. Comparison with combinations produced in predation contexts indicated that social call combinations are more varied in number of classes and structural complexity than the former, perhaps due to the greater variety of social contexts. However, in meerkats, combinations of functionally referential calls have been documented in predation but not social contexts, suggesting that both social and predation pressures may play a role in the evolution of combinatoriality in animal communication.

}, keywords = {call combination, meerkat, natural observations, social context, vocal communication}, issn = {00033472}, doi = {10.1016/j.anbehav.2016.12.014}, url = {http://linkinghub.elsevier.com/retrieve/pii/S0003347216303463}, author = {Collier, Katie and Townsend, Simon W.} } @article {52572, title = {Gestural development of chimpanzees in the wild: the impact of interactional experience}, journal = {Animal Behaviour}, volume = {134}, year = {2017}, month = {Jan-12-2017}, pages = {271 - 282}, abstract = {

To understand the complexity involved in animal signalling, studies have mainly focused on repertoire size and information conveyed in vocalizations of birds and nonhuman primates. However, recent studies on gestural abilities of nonhuman primates have shown that we also need a detailed understanding of other communicative modalities and underlying cognitive skills to grasp this phenomenon in detail. Here, we thus examined gestural signalling of chimpanzees, Pan troglodytes, living in two communities in the wild (Kanyawara, Uganda; Ta\ï South, Co^te d\&$\#$39;Ivoire) with a special focus on the influence of the social environment on signal development. Specifically, we investigated to what extent specific social factors, namely behavioural context, interaction rates and maternal proximity, affect gestural production (i.e. gesture frequency, sequences and repertoire size). We used a combination of video recordings and focal scans obtained from 11 infants aged between 9 and 69 months during 1145 h of observation throughout two consecutive field periods. Overall, we found that social play was the context in which the highest number of gestures occurred. While gesture frequency and repertoire size increased with higher inter- action rates with nonmaternal conspecifics and the number of previous interaction partners, no effect was found for interaction rates with mothers. Our results thus imply that infants of social mothers may have a head start in life. Moreover, we provide hitherto undocumented evidence for sex differences in gestural signalling, which may reflect the differential importance of early socialization for chimpanzee males and females. Gestural development thus relies heavily on interactional experiences with con- specifics, which adds support for gestural acquisition via the learning mechanism of \‘social negotiation\’ in great apes.

}, keywords = {chimpanzee, communication, development, gestures, interactional experience, ontogeny, Pan troglodytes}, issn = {00033472}, doi = {10.1016/j.anbehav.2016.12.018}, url = {http://linkinghub.elsevier.com/retrieve/pii/S000334721630361X}, author = {Fr{\"o}hlich, Marlen and M{\"u}ller, Gudrun and Zeitr{\"a}g, Claudia and Wittig, Roman M. and Pika, Simone} } @article {52566, title = {Grunt to go-Vocal coordination of group movements in redfronted lemurs}, journal = {Ethology}, volume = {123}, year = {2017}, month = {Jan-12-2017}, pages = {894 - 905}, abstract = {

To remain cohesive as a group, individuals must coordinate their movements between resources. In many species, vocalisations are used in this context. While some species have specific movement calls, others use calls which are also employed in different contexts. The use of such multicontextual calls has rarely been studied quantitatively, especially during both the pre-departure and departure period associated with collective decisions. We thus investigated the use of close calls (\“grunts\”) for the coordination of collective movements in four groups of wild redfronted lemurs (Eulemur rufifrons) in Kirindy Forest, Western Madagascar. Group movements are started by an initiator, who moves away from the group and is joined by followers setting out in the same direction. We observed collective movements and recorded vocalisations from 18 focal individuals (54 movements recorded for followers, 21 for initiators). The grunt rate of both initiators and followers was higher in the pre-departure period than in a control context (i.e., during foraging). Initiators of collective movements grunted more often than followers in the pre-departure period as well as at individual departure. The latter difference was due to the initiators\’ grunt rates increasing earlier than the followers\’ and remaining at an elevated level for longer. These observations suggest that grunts serve to coordinate the departure by indicating the individual\&$\#$39;s readiness to move. The pre-departure period, in which both initiators and followers showed an elevated grunt rate, may provide the basis for a shared decision on departure time. The difference in initiator and follower call rates suggests that grunts may have a recruitment function, but playback experiments are required to test this potential function. Overall, our study describes how multicontextual close calls can function as movement calls, with changes in call rate providing a potential feedback mechanism for the timing of group movements. This study thus contributes to a more detailed understanding of the mechanisms of group coordination and collective decision-making.

}, doi = {10.1111/eth.2017.123.issue-1210.1111/eth.12663}, url = {http://doi.wiley.com/10.1111/eth.2017.123.issue-12}, author = {Sperber, Anna Lucia and Werner, Lynne M. and Kappeler, Peter M. and Fichtel, Claudia}, editor = {Wright, J.} } @article {52565, title = {Bottlenose dolphins that forage with artisanal fishermen whistle differently}, journal = {Ethology}, volume = {123}, year = {2017}, month = {Jan-12-2017}, pages = {906 - 915}, abstract = {

Acoustic communication is a taxonomically widespread phenomenon, crucial for social animals. We evaluate social sounds from bottlenose dolphins (Tursiops truncatus) of Laguna, southern Brazil, whose social structure is organized around a cooperative foraging tactic with artisanal fishermen. This tactic involves stereotyped and coordinated behaviour by dolphins and fishermen and is performed by a subset of the dolphin population, splitting it into two distinct social communities. We compared the acoustic parameters and type of whistles emitted by dolphins of the \“non-cooperative\” and \“cooperative\” communities, both during their interactions with fishermen and in times where dolphins were engaged in other types of foraging. Our findings show how dolphins\’ social sounds differ between foraging tactics and social communities. The frequencies of six whistle types (ascending, descending, concave, convex, multiple, flat) were significantly dependent on tactics and communities. Ascending whistles were more common than expected during foraging without fishermen, and among dolphins of the non-cooperative community. Whistle acoustic parameters (duration, number of inclination changes and inflection points, and initial, final, maximum, minimum frequencies) also varied between social communities. In general, whistles emitted by cooperative dolphins, mainly when not interacting with fishermen, tended to be shorter, had higher frequency and more inflections than those emitted by non-cooperative dolphins. These results suggest that different whistles may convey specific information among dolphins related to foraging, which we hypothesize promote social cohesion among members of the same social community. These differences in acoustic repertoires add a new dimension of complexity to this unique human\–animal interaction.

}, doi = {10.1111/eth.2017.123.issue-1210.1111/eth.12665}, url = {http://doi.wiley.com/10.1111/eth.2017.123.issue-12}, author = {Romeu, Bianca and Cantor, Mauricio and Bezamat, Carolina and Sim{\~o}es-Lopes, Paulo C. and Daura-Jorge, F{\'a}bio G.}, editor = {Ebensperger, L.} } @inbook {50785, title = {Primate Habitat Acoustics}, volume = {63}, year = {2017}, pages = {79 - 107}, publisher = {Springer International Publishing}, organization = {Springer International Publishing}, address = {Cham}, abstract = {

Natural habitats are not recording studios. Calls emitted in nature encounter an irregular assortment of hard surfaces that reflect and scatter the wave front, producing complicated patterns of constructive and destructive interference. The propagated wave front is subsequently disturbed by wind, thermal gradients, and atmospheric absorption. Collectively, these phenomena result in an unpredictable and untidy acoustic environment. Furthermore, thunder, rain, crashing waves, or the relentless chatter of biotic sources can result in high ambient-noise levels that may mask the signal, overwhelm the recipient, and obliterate significant nuances and embellishments. Thus, vocal communication is hampered by attenuation, reverberation, distortion, and acoustic disturbances. Accordingly, the twin components of vocal communication, sound production and acoustic perception, may have undergone persistent selection to counter the most prominent impediments to both hearing and being heard. Primates have radiated from rain forest to grassland and other habitats, and each habitat differs acoustically. Hence, there is reason to believe that the duration, amplitude, pitch, and composition of primate vocal repertoires, the timing of emissions, and the placement and orientation of vocalizers is not haphazard, but each has become tuned to the acoustic parameters of the natal habitat to heighten the clarity of vocal exchanges. This chapter begins with an overview of the acoustic properties of rain forest, riverine forest, and savanna habitats occupied by East African primates, which is followed by reviews of how primate calls become distorted when propagated in natural habitats and how distortion scores have been used to explore the acoustic adaptation hypothesis. Finally, significant opportunities for additional research are highlighted.

}, keywords = {acoustic adaptation hypothesis, ambient noise, amplitude fluctuation, animal vocalization, comparative bioacoustics, Distortion, excess attenuation, reverberation}, isbn = {978-3-319-59476-7}, issn = {0947-2657}, doi = {10.1007/978-3-319-59478-1}, url = {http://link.springer.com/10.1007/978-3-319-59478-1}, author = {Brown, Charles H. and Waser, Peter M.} } @article {50507, title = {Vocalizations of captive beluga whales, Delphinapterus leucas: Additional evidence for contact signature {\textquotedblleft}mixed{\textquotedblright} calls in belugas}, journal = {Marine Mammal Science}, volume = {33}, year = {2017}, month = {Jan-07-2017}, pages = {889 - 903}, doi = {10.1111/mms.2017.33.issue-310.1111/mms.12393}, url = {http://doi.wiley.com/10.1111/mms.2017.33.issue-3}, author = {Panova, Elena and Agafonov, Alexandr and Belikov, Roman and Melnikova, Faina} } @article {50505, title = {Individuality of distress and discomfort calls in neonates with bass voices: Wild-living goitred gazelles ( Gazella subgutturosa) and saiga antelopes ( Saiga tatarica)}, journal = {Ethology}, volume = {123}, year = {2017}, month = {Jan-05-2017}, pages = {386 - 396}, abstract = {

Neonate ruminants produce distress calls when captured by a predator and discomfort milk begging calls when hungry. In many neonate ruminants, the distress and discomfort calls are high-frequency vocalizations, in which the fundamental frequency is the key variable for recognition of their emotional arousal by caregivers. In contrast, in this study, we examine the low-frequency open-mouth distress and discomfort calls in the neonates of two species of wild-living ungulates, which clearly highlight vocal tract resonances (formants). In the goitred gazelle (Gazella subgutturosa), the distress calls were higher in fundamental frequency (f0) and in the first and third formants than the discomfort calls. The accuracy of classifying individuals by variables of distress calls with discriminant function analysis (67\%) was significantly lower than that of discomfort calls (85\%). In the saiga (Saiga tatarica), only the third formant was higher in the distress calls than in the discomfort calls. The accuracy of classifying individuals by variables of distress calls (89\%) did not differ significantly from that of discomfort calls (94\%). Thus, the use of acoustic cues to vocal identity and to the degree of arousal differs between the two species. Calls were significantly more individualistic in the saiga, probably because this species lives in large herds and neonates use a \‘following\’ antipredatory strategy, in which vocal individuality is crucial for mother\–offspring communication. In contrast, goitred gazelles live in smaller groups and neonates use a \‘hiding\’ antipredatory strategy. Accordingly, mothers can rely on additional environmental cues for spotting their young and this may decrease the necessity for individualization of the calls of neonates.

}, keywords = {acoustic behavior, antipredatory strategy, emotional arousal, mother-offspring communication, ruminants, vocal identity}, doi = {10.1111/eth.2017.123.issue-510.1111/eth.12607}, url = {http://doi.wiley.com/10.1111/eth.2017.123.issue-5}, author = {Volodin, Ilya A. and Sibiryakova, Olga V. and Frey, Roland and Efremova, Kseniya O. and Soldatova, Natalia V. and Zuther, Steffen and Kisebaev, Talgat B. and Salemgareev, Albert R. and Volodina, Elena V.} } @article {50502, title = {Age-dependent change in attention paid to vocal exchange rules in Japanese macaques}, journal = {Animal Behaviour}, volume = {129}, year = {2017}, month = {Jan-07-2017}, pages = {81 - 92}, abstract = {

The mechanisms underlying vocal development in nonhuman primates, so-called \‘nonlearners\’, are of special interest because they give an insight in how social factors can shape the expression of an already genetically determined vocal repertoire. Interestingly, recent studies suggest that the acquisition of the complex rules governing vocal exchanges (i.e. context-specific temporal and structural acoustic adjustments) may result from a socially guided development process, with social experience and parental selective feedback playing a key role. Among those conversational rules, call matching is a particularly remarkable phenomenon in Japanese macaques, Macaca fuscata, with interacting adult females matching the frequency range pattern of their own call with another female\&$\#$39;s preceding call. Here, we investigated whether fine-tuned acoustic adjustments during vocal exchanges in Japanese macaques are subject to developmental processes, specifically testing for the ability of individuals of different age classes to discriminate between vocal exchanges respecting, or not, the matching rule. We performed playback experiments in 10 adult and 10 1-year-old captive Japanese macaque females. Each subject was successively exposed to two stimuli: a pair of calls respecting call matching (i.e. two calls from two individuals with matched frequency ranges) and another pair of calls that did not. Adults discriminated better than juveniles whether stimuli respected the call-matching rule or not, and displayed significantly different levels of interest towards each stimulus type. The latency to look towards the loudspeaker was shorter, and the duration of the directed gaze was longer, after the playback that violated the matching expectation in every adult, but not in juveniles which seemingly displayed a random gaze response. Our findings support the conclusion that the matching rule is relevant for adults, but not for socially inexperienced young monkeys which may not have had enough experience of the conversational rules governing vocal exchanges.

}, keywords = {call matching, Japanese Macaque, nonhuman primate, playback experiment, vocal development, vocal exchange}, issn = {00033472}, doi = {10.1016/j.anbehav.2017.05.012}, url = {http://linkinghub.elsevier.com/retrieve/pii/S0003347217301495}, author = {Bouchet, H{\'e}l{\`e}ne and Koda, Hiroki and Lemasson, Alban} } @article {50500, title = {Voices of Africa: acoustic predictors of human male vocal attractiveness}, journal = {Animal Behaviour}, volume = {127}, year = {2017}, month = {Jan-05-2017}, pages = {205 - 211}, abstract = {

Robust evidence shows that voice quality affects various social interactions, including mate preferences. Previous research found that male voices perceived as attractive are characterized by low voice pitch, lower or sexually typical formants and relatively high breathiness. These features tend to be seen as markers of an individual\&$\#$39;s quality as a potential mate. Although there are considerable differences between languages in vocal parameters that could influence the perceived attractiveness, the above-mentioned findings rely on research based mainly on participants from European or North American countries. In our study, we therefore tested the main acoustic predictors of vocal attractiveness using two male samples from Cameroon and Namibia. Standardized vocal recordings were then assessed for vocal attractiveness by a panel of female raters from the Czech Republic. Our results show that in the Cameroonian voices, fundamental frequency was strongly negatively associated with perceived vocal attractiveness. In the Namibian sample, however, it was not the fundamental frequency but lower mean formants and harmonics-to-noise ratio that were negatively associated with vocal attractiveness. This pattern may be partly attributed to differences in morphological characteristics such as the body mass index, indicating variation across individual populations.

}, keywords = {attractiveness, body mass index, formant, fundamental frequency, human, male, sexual selection, undernutrition, voice, y harmonics-to-noise ratio}, issn = {00033472}, doi = {10.1016/j.anbehav.2017.03.014}, url = {http://linkinghub.elsevier.com/retrieve/pii/S0003347217300866}, author = {{\v S}ebesta, Pavel and Kleisner, Karel and Ture{\v c}ek, Petr and Ko{\v c}nar, Tom{\'a}{\v s} and Akoko, Robert Mbe and T{\v r}ebick{\'y}, V{\'\i}t and Havl{\'\i}{\v c}ek, Jan} } @article {50498, title = {To seek or speak? Dual function of an acoustic signal limits its versatility in communication}, journal = {Animal Behaviour}, volume = {127}, year = {2017}, month = {Jan-05-2017}, pages = {135 - 152}, abstract = {

The perception of different attributes of conspecifics is an integral part of intraspecific communication. It can facilitate the recognition of interaction partners or the assessment of potential mates. Acoustic signals can encode fine-scaled information through the interplay of acoustic variability and specificity. A reliable vocal signature is both unique within a class and variable between classes. Therefore, acoustic complexity might be associated with the number of classes to be discriminated. We investigated the assumption that limitations to signal design may affect the communicative functionality of a signal. To do so, we chose a signal with potentially dual functionality which may therefore display such limitations. In bats, echolocation is used primarily for foraging and orientation but there is increasing support for its additional role in communication. An acoustic analysis of echolocation pulses of the bat Rhinolophus clivosus confirmed sex and individual vocal signatures in echolocation pulses. A habituation\–dishabituation playback experiment suggested that bats perceived these signatures because listening bats clearly discriminated between the sexes (two classes) and between individuals (representatives of a multiclass category), although to different degrees. The simple acoustic structure of these vocalizations provides sufficient specificity for sex discrimination but has limitations for individual discrimination because pulse parameters of individuals increasingly overlapped with increasing group size. We conclude that selection for the primary function of echolocation restricts the acoustic space available for communication. However, we frequently observed echolocation pulses with conspicuous structural modifications. Statistical analyses revealed that these vocalizations yielded increased individual distinctiveness. Such added systematic variation may indicate a communicative function and perhaps a signalling intent of the emitter, although the latter has yet to be tested. The findings suggest that the required specificity for effective communication could be obtained through modification of echolocation variants when adaptations for orientation and foraging constrain the evolution of complex communication signatures.

}, keywords = {acoustic communication, bats, co-option, constraints, eavesdropping, echolocation, habituation{\textendash}dishabituation playback, individual and sex discrimination, signal design, vocal signatures}, issn = {00033472}, doi = {10.1016/j.anbehav.2017.03.005}, url = {http://linkinghub.elsevier.com/retrieve/pii/S0003347217300775}, author = {Anna Bastian and David Steve Jacobs} } @article {50497, title = {Social calls honestly signal female competitive ability in Asian particoloured bats}, journal = {Animal Behaviour}, volume = {127}, year = {2017}, month = {Jan-05-2017}, pages = {101 - 108}, abstract = {

Why a variety of social animals vocalize during agonistic foraging interactions remains obscure. One possibility is that these signals advertise the signaller\&$\#$39;s competitive ability, playing a role in the defence of food resources, yet there is limited evidence in support of this idea. Here, we used adult female Asian particoloured bats, Vespertilio sinensis, to test whether individual variation in competitive ability when foraging can be explained by social calls. Using synchronized infrared video and audio recording, we monitored bat social vocalizations, dominance rank and weight gain in triads under controlled food conditions. Additionally, subsequent playbacks, consisting of experimental stimuli, echolocation pulses and silence, were presented to feeding bats in a laboratory. Analyses showed that females uttered low-frequency social calls composed of one to five syllable types during feeding competition. The rates of social vocalizations increased with reduced food availability. Interestingly, dominance score and weight gain correlated weakly with body size, but positively with call rate and associated parameters. Playback of social calls inhibited the visits of bats to the focal food dish compared to playback of silence and echolocation pulses. The amount of food consumed was greatly reduced in the presence of experimental stimuli versus controls. Collectively, these results highlight that acoustic signals serve as an honest indicator of bat competitive ability.

}, keywords = {aggressive interaction, bats, competitive ability echolocation, foraging, social call}, issn = {00033472}, doi = {10.1016/j.anbehav.2017.03.012}, url = {http://linkinghub.elsevier.com/retrieve/pii/S0003347217300842}, author = {Luo, Bo and Lu, Guanjun and Chen, Kelly and Guo, Dongge and Huang, Xiaobin and Liu, Ying and Feng, Jiang} } @article {50496, title = {Dwarf mongooses use sex and identity cues in isolation calls to discriminate between callers}, journal = {Animal Behaviour}, volume = {127}, year = {2017}, month = {Jan-05-2017}, pages = {23 - 31}, abstract = {

The information transmitted by acoustic signals has attracted much scientific interest in recent years. However, isolation calls, which are long-distance vocalizations used by lost group members to reunite with their social group, have been surprisingly neglected. These calls assist in maintaining group cohesion and are thus particularly important in species that depend on the group for survival or reproduction such as cooperative breeders. Our study therefore examined the information transmitted by the isolation vocalization in a wild cooperatively breeding carnivore: the dwarf mongoose, Helogale parvula. We ran an acoustic analysis for informative cues within isolation calls, and conducted a series of playback experiments to identify whether mongooses could discriminate between callers based on these cues. The acoustic structure of dwarf mongoose isolation vocalizations contained information concerning the caller\&$\#$39;s identity, sex and potentially also group membership. Target mongooses discriminated between callers of their own and other groups and biased their response based on the sex of the caller. They responded more quickly and for longer, and approached more closely, for calls of foreign females than calls of female group mates. This is the first time that sex specificity has been demonstrated in the vocalization of an herpestid, and we suggest that dwarf mongooses eavesdrop on the calls of isolated foreigners and may use isolation calls to attract and identify potential mates.

}, keywords = {acoustic analysis, dwarf mongoose, familiarity, Helogale parvula, individuality, isolation vocalizations, playbacks, sex specificity}, issn = {00033472}, doi = {10.1016/j.anbehav.2017.02.019}, url = {http://linkinghub.elsevier.com/retrieve/pii/S0003347217300660}, author = {Rubow, Janneke and Cherry, Michael I. and Sharpe, Lynda L.} } @article {50495, title = {Calling for help: dwarf mongoose recruitment calls inform receivers about context and elicit disparate responses}, journal = {Animal Behaviour}, volume = {127}, year = {2017}, month = {Jan-05-2017}, pages = {7 - 14}, abstract = {

Social complexity and communicative complexity appear to have coevolved in terrestrial vertebrates. Understanding the information conveyed within the social signals of group-living taxa can illuminate the selection pressures impacting on a species and help to identify the factors promoting sociality. Within vocal communication, recruitment calls are of great importance to many social species, helping to maintain group cohesion and facilitating cooperative behaviour. Yet recruitment vocalizations have received limited scientific attention and it is not clear whether they convey context-specific information to receivers. We investigated the recruitment calls of wild dwarf mongooses, Helogale parvula, to ascertain whether they showed context-specific acoustic differences and whether receivers displayed context-specific responses to recruitment calls in the absence of external cues. We recorded recruitment calls (from four wild groups of dwarf mongooses) from two contexts: when an individual became separated from its group and when an individual encountered a snake. Acoustic analysis revealed that calls from the two contexts differed in acoustic structure and were distinguishable with a discriminant function analysis. Playbacks of calls from both contexts successfully recruited target mongooses, but snake calls elicited a stronger reaction (with mongooses vigilant for longer and approaching the speaker more closely). More importantly, target mongooses also displayed behaviours that were unique to call context, exhibiting head bobbing, creeping and searching of the vegetation during snake call playbacks but never during isolation call playbacks. We conclude that dwarf mongoose recruitment calls refer to context and are perceived as functionally referential by receivers.

}, keywords = {acoustic analysis, context-specific, dwarf mongoose, functional reference, Helogale parvula, mobbing, recruitment calls}, issn = {00033472}, doi = {10.1016/j.anbehav.2017.02.018}, url = {http://linkinghub.elsevier.com/retrieve/pii/S0003347217300659}, author = {Rubow, Janneke and Cherry, Michael I. and Sharpe, Lynda L.} } @article {50494, title = {Subharmonics increase the auditory impact of female koala rejection calls}, journal = {Ethology}, volume = {123}, year = {2017}, month = {Jan-08-2017}, pages = {571 - 579}, abstract = {

Although non-linear phenomena are common in human and non-human animal vocalisations, their functional relevance remains poorly understood. One theory posits that non-linear phenomena generate unpredictability in vocalisations, which increases the auditory impact of vocal signals, and makes animals less likely to habituate to call repetition. Female koalas (Phascolarctos cinereus) produce vocal signals when they reject male copulation attempts that contain relatively high levels of non-linear phenomena, and thus may function as attention grabbing vocal signals during the breeding season. To test this hypothesis, we used playback experiments: firstly, to determine whether female rejection calls induce heightened behavioural responses in free-ranging male koalas during the breeding season, and secondly, to examine how the relative amount of non-linear phenomena in rejection calls influences male behavioural response. The results show that male koalas look for longer towards speakers broadcasting playback sequences of male bellows followed by a series of female rejection calls than those broadcasting only male bellows. In addition, female rejection call sequences with more subharmonics, higher harmonics-to-noise ratios, and less biphonation produced the greatest male looking responses. Our findings support the hypothesis that female koala rejection calls function to grab male attention during the breeding season, and indicate that subharmonics are the main acoustic feature that increases the auditory impact of these vocal signals.

}, keywords = {koalas, mammal vocal communication, non-linear phenomena}, doi = {10.1111/eth.2017.123.issue-810.1111/eth.12628}, url = {http://doi.wiley.com/10.1111/eth.2017.123.issue-8}, author = {Charlton, Benjamin D. and Watchorn, Darcy J. and Whisson, Desley A.} } @article {50492, title = {The effects of cultural drift on geographic variation in echolocation calls of the Chinese rufous horseshoe bat ( Rhinolophus sinicus)}, journal = {Ethology}, volume = {123}, year = {2017}, month = {Jan-08-2017}, pages = {532 - 541}, abstract = {

Drift, selection, or their combined effects commonly drive geographic variation in traits. Clarifying the relative roles of each process is a long-standing research goal in evolutionary biology. Acoustic signals of bats are a phenotypic characteristic that plays an important role in social organization and species recognition. We extensively sampled the Chinese rufous horseshoe bat (Rhinolophus sinicus) throughout China and Vietnam and reconstructed a species phylogeny to better understand the patterns and causes of the geographic variation of acoustic signals. Our results showed that the resting frequency (RF) of calls varied with latitude, sex, and distance among different colony locations. RF differences were not correlated with genetic distance (based on only one nuclear locus and the mitochondrial locus), climatic factors (mean annual temperature and mean annual precipitable water), or body size, although differences in calls increased with distance among various populations. This suggests that cultural drift may play more important roles than genetic drift and acoustic adaptation in shaping acoustic differences within regions in R. sinicus.

}, keywords = {drift, geographic variation, resting frequency, Rhinolophus sinicus, selection}, doi = {10.1111/eth.2017.123.issue-810.1111/eth.12627}, url = {http://doi.wiley.com/10.1111/eth.2017.123.issue-8}, author = {Xie, Lifen and Sun, Keping and Jiang, Tinglei and Liu, Sen and Lu, Guanjun and Jin, Longru and Feng, Jiang} } @article {50489, title = {Conflict or consensus? Synchronous change in mother{\textendash}young vocal communication across weaning in the cat}, journal = {Animal Behaviour}, volume = {130}, year = {2017}, month = {Jan-08-2017}, pages = {233 - 240}, abstract = {

Since parent\–offspring conflict theory was first proposed, a number of studies in a range of mammalian species have questioned its importance, suggesting that coordination, rather than conflict, occurs during weaning. In this study we propose a set of behaviours for studying the development of the mother\–offspring relationship: offspring separation calls and the corresponding maternal response, which can be used to describe the continually developing motivational changes in both parties accompanying weaning. We recorded and analysed separation calls of kittens of the domestic cat, Felis silvestris catus, during the first two postnatal months, and performed playback experiments to observe their mothers\&$\#$39; behavioural response. Three different stimuli were played back: calls of the mothers\&$\#$39; kittens at their correct age, calls of their kittens from an earlier age (1 week old) and a control sound. We found that kittens\&$\#$39; separation calls changed in several respects across the 8 weeks of the study. After the first postnatal month, the number, intensity and fundamental frequency of calls declined markedly, while kittens\&$\#$39; latency to call increased. In parallel, we found that during playback tests, mothers\&$\#$39; willingness to return to the nest or reunite with their kittens decreased notably as the kittens approached weaning age. Since this decline was present even when mothers were played back the calls of their own kittens previously recorded at an earlier age, we conclude that the decline in responsiveness was not due to a change in the kittens\&$\#$39; vocalizations, but rather to a change in the mothers\&$\#$39; motivational state. Our findings support the view that weaning in the domestic cat is a well-synchronized process between mothers and offspring, at least under the favourable nutritional conditions of the present study.

}, keywords = {domestic cat, Felis silvestris catus, mammal, motivation, parent{\textendash}offspring conflict, separation call, vocal communication, weaning}, issn = {00033472}, doi = {10.1016/j.anbehav.2017.06.025}, url = {http://linkinghub.elsevier.com/retrieve/pii/S0003347217302002}, author = {B{\'a}nszegi, Ox{\'a}na and Szenczi, P{\'e}ter and Urrutia, Andrea and Hudson, Robyn} } @article {50486, title = {Tennis grunts communicate acoustic cues to sex and contest outcome}, journal = {Animal Behaviour}, volume = {130}, year = {2017}, month = {Jan-08-2017}, pages = {47 - 55}, abstract = {

Despite their ubiquity in human behaviour, the communicative functions of nonverbal vocalizations remain poorly understood. Here, we analysed the acoustic structure of tennis grunts, nonverbal vocal- izations produced in a competitive context. We predicted that tennis grunts convey information about the vocalizer and context, similar to nonhuman vocal displays. Speci fi cally, we tested whether the fundamental frequency (F0) of tennis grunts conveys static cues to a player\&$\#$39;s sex, height, weight, and age, and covaries dynamically with tennis shot type (a proxy of body posture) and the progress and outcome of male and female professional tennis contests. We also performed playback experiments (using natural and resynthesized stimuli) to assess the perceptual relevance of tennis grunts. The F0 of tennis grunts predicted player sex, but not age or body size. Serve grunts had higher F0 than forehand and backhand grunts, grunts produced later in contests had higher F0 than those produced earlier, and grunts produced during contests that players won had a lower F0 than those produced during lost contests. This difference in F0 between losses and wins emerged early in matches, and did not change in magnitude as the match progressed, suggesting a possible role of physiological and/or psychological factors manifesting early or even before matches. Playbacks revealed that listeners use grunt F0 to infer sex and contest outcome. These fi ndings indicate that tennis grunts communicate information about both the vocalizer and contest, consistent with nonhuman mammal vocalizations.

}, keywords = {dominance, fundamental frequency, nonverbal vocalizations, pitch, tennis grunts, vocal communication}, issn = {00033472}, doi = {10.1016/j.anbehav.2017.06.022}, url = {http://linkinghub.elsevier.com/retrieve/pii/S0003347217301975}, author = {Raine, Jordan and Pisanski, Katarzyna and Reby, David} } @article {50485, title = {Feeling anxious? The mechanisms of vocal deception in tufted capuchin monkeys}, journal = {Animal Behaviour}, volume = {130}, year = {2017}, month = {Jan-08-2017}, pages = {37 - 46}, abstract = {

An ability to deceive conspeci fi cs is thought to have favoured the evolution of large brains in social animals, but evidence that such behaviours require cognitive complexity is lacking. Tufted capuchin monkeys ( Sapajus spp.) have been documented to use false alarm calls during feeding in a manner that functions to deceive competitors. However, comparative evidence suggests that the production of vo- calizations by nonhuman primates is largely underpinned by emotional mechanisms, calling into question more cognitive interpretations of this behaviour. To determine whether emotional states are plausibly necessary and suf fi cient to proximately explain deceptive alarm call production, we examined the association between self-directed behaviours (SDBs), as a proxy for anxiety, and the production of spontaneous false alarm calls among tufted capuchins. Speci fi cally, we predicted that if anxiety is necessary for the production of false alarms, then individuals that produce spontaneous false alarms should exhibit more SDBs in those contexts in which they call. If anxiety is also suf fi cient to explain the false alarm call production, then we predicted that individuals that call more in a given context would show higher rates of SDBs in that context, and that high rates of calling would be temporally associated with high rates of SDBs. Our results support the contention that states of anxiety are necessary for an individual to spontaneously produce false alarms, but that such states are not suf fi cient to explain patterns of calling. The link between anxiety and deceptive calling thus appears complex, and cognitively based decision-making processes may play some role in call production.

}, keywords = {affect, alarm calls, anxiety, deceptive behaviour, emotions, primates, scratching, self-directed behaviours, vocalizations, within-group contest competition}, issn = {00033472}, doi = {10.1016/j.anbehav.2017.06.008}, url = {http://linkinghub.elsevier.com/retrieve/pii/S0003347217301835}, author = {Kean, Donna and Tiddi, Barbara and Fahy, Martin and Heistermann, Michael and Schino, Gabriele and Wheeler, Brandon C.} } @article {47816, title = {Using nonlinear time warping to estimate North Pacific right whale calling depths in the Bering Sea}, journal = {The Journal of the Acoustical Society of America}, volume = {141}, year = {2017}, month = {Jan-05-2017}, pages = {3059 - 3069}, abstract = {

Calling depth distributions are estimated for two types of calls produced by critically endangered eastern North Pacific right whales (NPRWs) in the Bering Sea, using passive acoustic data collected with bottom-mounted hydrophone recorders. Nonlinear time resampling of 12 NPRW \“upcalls\” and 20 \“gunshots\” recorded in a critical NPRW habitat isolated individual normal mode arrivals from each call. The relative modal arrival times permitted range estimates between 1 and 40\ km, while the relative modal amplitudes permitted call depth estimates, provided that environmental inversions were obtained from high signal-to-noise ratio calls. Gunshot sounds were generally only produced at a few meters depth, while upcall depths clustered between 10 and 25\ m, consistent with previously published bioacoustic tagging results from North Atlantic right whales. A Wilcoxon rank sum test rejected the null hypothesis that the mean calling depths of the two call types were the same (p\ =\ 2.9\ \×\ 10\−5); the null hypothesis was still rejected if the sample set was restricted to one call per acoustic encounter (p\ =\ 0.02). Propagation modeling demonstrates that deeper depths enhance acoustic propagation and that source depth estimates impact both NPRW upcall source level and detection range estimates.

}, issn = {0001-4966}, doi = {10.1121/1.4982200}, url = {http://asa.scitation.org/doi/10.1121/1.4982200}, author = {Thode, Aaron and Bonnel, Julien and Thieury, Margaux and Fagan, Aileen and Verlinden, Chris and Wright, Dana and Crance, Jessica} } @article {47815, title = {Horseshoe bats and Old World leaf-nosed bats have two discrete types of pinna motions}, journal = {The Journal of the Acoustical Society of America}, volume = {141}, year = {2017}, month = {Jan-05-2017}, pages = {3011 - 3017}, abstract = {

Horseshoe bats (Rhinolophidae) and the related Old World leaf-nosed bats (Hipposideridae) both show conspicuous pinna motions as part of their biosonar behaviors. In the current work, the kinematics of these motions in one species from each family (Rhinolophus ferrumequinum and Hipposideros armiger) has been analyzed quantitatively using three-dimensional tracking of landmarks placed on the pinna. The pinna motions that were observed in both species fell into two categories: In \“rigid rotations\” motions the geometry of the pinna was preserved and only its orientation in space was altered. In \“open\–close motions\” the geometry of the pinna was changed which was evident in a change of the distances between the landmark points. A linear discriminant analysis showed that motions from both categories could be separated without any overlap in the analyzed data set. Hence, bats from both species have two separate types of pinna motions with apparently no transitions between them. The deformations associated with open\–close pinna motions in Hipposideros armiger were found to be substantially larger compared to the wavelength associated with the largest pulse energy than in Rhinolophus ferrumequinum (137\% vs 99\%). The role of the two different motions in the biosonar behaviors of the animals remains to be determined.

}, issn = {0001-4966}, doi = {10.1121/1.4982042}, url = {http://asa.scitation.org/doi/10.1121/1.4982042}, author = {Yin, Xiaoyan and Qiu, Peiwen and Yang, Lili and M{\"u}ller, Rolf} } @article {47814, title = {Three-dimensional sonar beam-width expansion by Japanese house bats ( Pipistrellus abramus ) during natural foraging}, journal = {The Journal of the Acoustical Society of America}, volume = {141}, year = {2017}, month = {Jan-05-2017}, pages = {EL439 - EL444}, abstract = {

Three-dimensional directivity patterns of sonar sounds emitted by Japanese house bats (Pipistrellus abramus) during natural foraging were measured by a 44-channel microphone array. Just before prey capture, the terminal frequency (TF) of emitted sounds decreased, and the beam width (mean\ \±\ standard deviation) expanded from 40\ \±\ 10\° to 63\ \±\ 9\° (horizontal) and from 32\ \±\ 10\° to 52\ \±\ 7\° (vertical). P. abramus decrease the TF to simultaneously expand the beam width in both the horizontal and vertical planes, while retaining the target within the three-dimensional acoustic field of view at the final stage of capture.

}, issn = {0001-4966}, doi = {10.1121/1.4981934}, url = {http://asa.scitation.org/doi/10.1121/1.4981934}, author = {Motoi, Kazuya and Sumiya, Miwa and Fujioka, Emyo and Hiryu, Shizuko} } @article {47324, title = {Upcall production by southern right whale ( Eubalaena australis) mother-calf pairs may be independent of diel period in a nursery area}, journal = {Marine Mammal Science}, year = {2017}, month = {Jan-02-2017}, doi = {10.1111/mms.12382}, url = {http://doi.wiley.com/10.1111/mms.12382}, author = {Dombroski, Julia R. G. and Parks, Susan E. and Groch, Karina R. and Flores, Paulo A. C. and Sousa-lima, Renata S.} } @article {47323, title = {Estimation of minke whale abundance from an acoustic line transect survey of the Mariana Islands}, journal = {Marine Mammal Science}, year = {2017}, month = {Jan-03-2017}, abstract = {

The minke whale is one of the most abundant species of baleen whales worldwide, yet is rarely sighted in subtropical waters. In the North Pacific, they produce a dis- tinctive sound known as the \“boing,\” which can be used to acoustically localize indi- viduals. A vessel-based survey using both visual and passive acoustic monitoring was conducted during the spring of 2007 in a large (616,000 km 2 ) study area encom- passing the Mariana Islands. We applied line transect methods to data collected from a towed hydrophone array to estimate the abundance of calling minke whales in our study area. No minke whales were sighted, but there were hundreds of acoustic detections of boings. Computer algorithms were developed to localize calling minke whales from acoustic recordings, resulting in over 30 independent localizations, a six-fold increase over those estimated during the survey. The two best estimates of abundance of calling minke whales were determined to be 80 and 91 animals (0.13 and 0.15 animals per 1,000 km2, respectively; CV = 34\%). These are the first den- sity and abundance estimates for calling minke whales using towed hydrophone array surveys, and the first estimates for this species in the Mariana Islands region. These are considered minimum estimates of the true number of minke whales in the study area.

}, keywords = {Balaenoptera acutorostrata, density esti- mation, Mariana Islands, marine mammals., minke whale, Pacific, passive acoustics}, doi = {10.1111/mms.12397}, url = {http://doi.wiley.com/10.1111/mms.12397}, author = {Norris, Thomas F. and Dunleavy, Kerry J. and Yack, Tina M. and Ferguson, Elizabeth L.} } @article {47320, title = {To seek or speak? Dual function of an acoustic signal limits its versatility in communication}, journal = {Animal Behaviour}, volume = {127}, year = {2017}, month = {Jan-05-2017}, pages = {135 - 152}, abstract = {

The perception of different attributes of conspecifics is an integral part of intraspecific communication. It can facilitate the recognition of interaction partners or the assessment of potential mates. Acoustic signals can encode fine-scaled information through the interplay of acoustic variability and specificity. A reliable vocal signature is both unique within a class and variable between classes. Therefore, acoustic complexity might be associated with the number of classes to be discriminated. We investigated the assumption that limitations to signal design may affect the communicative functionality of a signal. To do so, we chose a signal with potentially dual functionality which may therefore display such limitations. In bats, echolocation is used primarily for foraging and orientation but there is increasing support for its additional role in communication. An acoustic analysis of echolocation pulses of the bat Rhinolophus clivosus confirmed sex and individual vocal signatures in echolocation pulses. A habituation\–dishabituation playback experiment suggested that bats perceived these signatures because listening bats clearly discriminated between the sexes (two classes) and between individuals (representatives of a multiclass category), although to different degrees. The simple acoustic structure of these vocalizations provides sufficient specificity for sex discrimination but has limitations for individual discrimination because pulse parameters of individuals increasingly overlapped with increasing group size. We conclude that selection for the primary function of echolocation restricts the acoustic space available for communication. However, we frequently observed echolocation pulses with conspicuous structural modifications. Statistical analyses revealed that these vocalizations yielded increased individual distinctiveness. Such added systematic variation may indicate a communicative function and perhaps a signalling intent of the emitter, although the latter has yet to be tested. The findings suggest that the required specificity for effective communication could be obtained through modification of echolocation variants when adaptations for orientation and foraging constrain the evolution of complex communication signatures.

}, keywords = {acoustic communication, bats, co-option, constraints, eavesdropping, echolocation, habituation{\textendash}dishabituation playback, individual and sex discrimination, signal design, vocal signatures}, issn = {00033472}, doi = {10.1016/j.anbehav.2017.03.005}, url = {http://linkinghub.elsevier.com/retrieve/pii/S0003347217300775}, author = {Anna Bastian and David Steve Jacobs} } @article {47292, title = {Testing the performances of automated identification of bat echolocation calls: A request for prudence}, journal = {Ecological Indicators}, volume = {78}, year = {2017}, month = {Jan-07-2017}, pages = {416 - 420}, abstract = {

Echolocating bats are surveyed and studied acoustically with bat detectors routinely and worldwide, yet identification of species from calls often remains ambiguous or impossible due to intraspecific call variation and/or interspecific overlap in call design. To overcome such difficulties and to reduce workload, automated classifiers of echolocation calls have become popular, but their performance has not been tested sufficiently in the field. We examined the absolute performance of two commercially available programs (SonoChiro and Kaleidoscope) and one freeware package (BatClassify). We recorded noise from rain and calls of seven common bat species with Pettersson real-time full spectrum detectors in Sweden. The programs could always (100\%) distinguish rain from bat calls, usually (68\–100\%) identify bats to group ( Nyctalus/Vespertilio/Eptesicus, Pipistrellus, Myotis, Plecotus, Barbastella ) and usually (83\–99\%) recognize typical calls of some species whose echolocation pulses are structurally distinct ( Pipistrellus pygmaeus , Barbastella barbastellus ). Species with less characteristic echolocation calls were not identified reliably, including Vespertilio murinus (16\–26\%), Myotis spp. (4\–93\%) and Plecotus auritus (0\–89\%). All programs showed major although different shortcomings and the often poor performance raising serious concerns about the use of automated classifiers for identification to species level in research and surveys. We highlight the importance of validating output from automated classifiers, and restricting their use to specific situations where identification can be made with high confidence. For comparison we also present the result of a manual identification test on a random subset of the files used to test the programs. It showed a higher classification success but performances were still low for more problematic taxa.

}, keywords = {Biosonar, methodology, software, species identification, ultrasound}, issn = {1470160X}, doi = {10.1016/j.ecolind.2017.03.023}, url = {http://linkinghub.elsevier.com/retrieve/pii/S1470160X17301401}, author = {Rydell, Jens and Nyman, Stefan and Ekl{\"o}f, Johan and Jones, Gareth and Russo, Danilo} } @article {17270, title = {Remarkable vocal identity in wild-living mother and neonate saiga antelopes: a specialization for breeding in huge aggregations?}, journal = {The Science of Nature}, volume = {104}, year = {2017}, month = {Jan-04-2017}, abstract = {

Saiga antelopes Saiga tatarica tatarica give birth in large aggregations, and offspring follow the herd soon after birth. Herding is advantageous as anti-predator strategy; however, communication between mothers and neonates is strongly complicated in large aggregations. Individual series of nasal and oral contact calls of mother and neonate saiga antelopes were selected from recordings made with automated recording systems placed near the hiding neonates on the saiga breeding grounds in Northern Kazakhstan during synchronized parturitions of 30,000 calving females. We used for comparison of the acoustic structure of nasal and oral contact calls 168 nasal calls of 18 mothers, 192 oral calls of 21 mothers, 78 nasal calls of 16 neonates, and 197 oral calls of 22 neonates. In the oral calls of either mothers or neonates, formant frequencies were higher and the duration was longer than in the nasal calls, whereas fundamental frequencies did not differ between oral and nasal calls. Discriminant function analysis (DFA) based on six acoustic variables, accurately classified individual identity for 99.4\% of oral calls of 18 mothers, for 89.3\% of nasal calls of 18 mothers, and for 94.4\% of oral calls of 18 neonates. The average value of correct classification to individual was higher in mother oral than in mother nasal calls and in mother oral calls than in neonate oral calls; no significant difference was observed between mother nasal and neonate oral calls. Variables mainly responsible for vocal identity were the fundamental frequency and the second and third formants in either mothers or neonates, and in either nasal or oral calls. The high vocal identity of mothers and neonates suggests a powerful potential for the mutual mother-offspring recognition in dense aggregations of saiga antelopes as an important component of their survival strategy.

}, keywords = {maternal care in herds, mother-offspring communication, offspring survival, vocal identity}, issn = {0028-1042}, doi = {10.1007/s00114-017-1433-0}, url = {http://link.springer.com/10.1007/s00114-017-1433-0}, author = {Sibiryakova, Olga V. and Volodin, Ilya A. and Frey, Roland and Zuther, Steffen and Kisebaev, Talgat B. and Salemgareev, Albert R. and Volodina, Elena V.} } @article {16462, title = {Two-stage detection of north Atlantic right whale upcalls using local binary patterns and machine learning algorithms}, journal = {Applied Acoustics}, volume = {120}, year = {2017}, month = {Jan-05-2017}, pages = {158 - 166}, abstract = {

In this paper, we investigate the effectiveness of two-stage classification strategies in detecting north Atlantic right whale upcalls. Time-frequency measurements of data from passive acoustic monitoring devices are evaluated as images. Vocalization spectrograms are preprocessed for noise reduction and tone removal. First stage of the algorithm eliminates non-upcalls by an energy detection algorithm. In the second stage, two sets of features are extracted from the remaining signals using contour-based and texture based methods. The former is based on extraction of time\–frequency features from upcall contours, and the latter employs a Local Binary Pattern operator to extract distinguishing texture features of the upcalls. Subsequently evaluation phase is carried out by using several classifiers to assess the effectiveness of both the contour-based and texture-based features for upcall detection. Comparing ROC curves of machine learning algorithms obtained from Cornell University\’s dataset reveals that LBP features improved performance accuracy up to 43\% over time\–frequency features. Classifiers such as the Linear Discriminant Analysis, Support Vector Machine, and TreeBagger achieve highest upcall detection rates with LBP features.

}, issn = {0003682X}, doi = {10.1016/j.apacoust.2017.01.025}, url = {http://linkinghub.elsevier.com/retrieve/pii/S0003682X17300774}, author = {Esfahanian, Mahdi and Erdol, Nurgun and Gerstein, Edmund and Zhuang, Hanqi} } @article {16409, title = {Potential for coupling the monitoring of bush-crickets with established large-scale acoustic monitoring of bats}, journal = {Methods in Ecology and Evolution}, year = {2017}, month = {Jan-01-2017}, abstract = {

Monitoring biodiversity over large spatial and temporal scales is crucial for assessing the impact of global changes and environmental mitigation measures. However, large-scale monitoring of invertebrates remains poorly developed despite the importance of these organisms in ecosystem functioning. Exciting possibilities applicable to professional and citizen science are offered by new recording techniques and methods of semi-automated species recognition based on sound detection.


Static broad-spectrum detectors deployed to record throughout whole nights have been recommended for standardised acoustic monitoring of bats, but they have the potential to also collect acoustic data for other species groups. Large-scale deployment of such systems is only viable when combined with robust automated species identification algorithms. Here we examine the potential of such a system for detecting, identifying and monitoring bush-crickets (Orthoptera of the family Tettigoniidae). We use incidental sound recordings generated by an extensive citizen science bat survey and recordings from intensive site surveys to test a semi-automated step-wise method with a classifier for assigning species identities. We assess species\’ diel activity patterns to make recommendations for survey timing and interpretation of existing nocturnal data sets and consider the feasibility of determining site occupancy.

Of six species of bush-crickets, the species classifier achieved over 85\% accuracy for three, speckled bush-cricket, dark bush-cricket and Roesel\&$\#$39;s bush-cricket. It should be possible to automatically scan recordings for these species with minimal manual validation. Further refinement of the classifier is required for the three remaining species, in particular for the acoustically similar short-winged conehead and long-winged conehead. Diel activity patterns are species specific and it may be necessary to adjust the hours over which the detectors record to increase detection of key species, but this must be weighed against the costs in terms of increased memory and battery use and equipment security during daytime.

We conclude that with logistical support and centralised semi-automated species identification it is now possible for the public to contribute to large-scale acoustic monitoring of Orthoptera while recording bats. Further innovation of sound classifier algorithms is needed and would be aided by improved reference sound libraries from multiple locations spanning species\’ ranges.

}, doi = {10.1111/2041-210X.12720}, url = {http://doi.wiley.com/10.1111/2041-210X.12720}, author = {Newson, Stuart E. and Bas, Yves and Murray, Ash and Gillings, Simon} } @article {16156, title = {Common nonsong social calls of humpback whales (Megaptera novaeangliae) recorded off northern Angola, southern Africa}, journal = {Marine Mammal Science}, volume = {33}, year = {2017}, month = {Jan-01-2017}, pages = {365 - 375}, doi = {10.1111/mms.2017.33.issue-110.1111/mms.12355}, url = {http://doi.wiley.com/10.1111/mms.2017.33.issue-1}, author = {Melinda L. Rekdahl and Tisch, Charlotte and Salvatore Cerchio and Howard C. Rosenbaum} } @article {16155, title = {Insights into Blainville{\textquoteright}s beaked whale (Mesoplodon densirostris) echolocation ontogeny from recordings of mother-calf pairs}, journal = {Marine Mammal Science}, volume = {33}, year = {2017}, month = {Jan-01-2017}, pages = {356 - 364}, doi = {10.1111/mms.2017.33.issue-110.1111/mms.12351}, url = {http://doi.wiley.com/10.1111/mms.2017.33.issue-1}, author = {Dunn, Charlotte and Claridge, Diane and John W. Durban and Shaffer, Jessica and David J. Moretti and Peter L. Tyack and Rendell, Luke} } @article {16154, title = {Southeastern Pacific humpback whales (Megaptera novaeangliae and their breeding grounds: Distribution and habitat preference of singers and social groups off the coast of Ecuador}, journal = {Marine Mammal Science}, volume = {33}, year = {2017}, month = {Jan-01-2017}, pages = {219 - 235}, doi = {10.1111/mms.2017.33.issue-110.1111/mms.12365}, url = {http://doi.wiley.com/10.1111/mms.2017.33.issue-1}, author = {O{\~n}a, Javier and Garland, Ellen C. and Denkinger, Judith} } @article {16153, title = {Seasonal acoustic behavior of blue whales ( Balaenoptera musculus ) in the Gulf of California, Mexico}, journal = {Marine Mammal Science}, volume = {33}, year = {2017}, month = {Jan-01-2017}, pages = {206 - 218}, doi = {10.1111/mms.2017.33.issue-110.1111/mms.12362}, url = {http://doi.wiley.com/10.1111/mms.2017.33.issue-1}, author = {Paniagua-Mendoza, Aurora and Gendron, Diane and Romero-Vivas, Eduardo} } @article {16152, title = {Using calls as an indicator for Antarctic blue whale occurrence and distribution across the southwest Pacific and southeast Indian Oceans}, journal = {Marine Mammal Science}, volume = {33}, year = {2017}, month = {Jan-01-2017}, pages = {172 - 186}, doi = {10.1111/mms.2017.33.issue-110.1111/mms.12373}, url = {http://doi.wiley.com/10.1111/mms.2017.33.issue-1}, author = {Balcazar, Naysa E. and Klinck, Holger and Nieukirk, Sharon L. and Mellinger, David K. and Klinck, Karolin and Dziak, Robert P. and Rogers, Tracey L.} } @article {16151, title = {Spatial and temporal patterns in the calling behavior of beluga whales, Delphinapterus leucas, in Cook Inlet, Alaska}, journal = {Marine Mammal Science}, volume = {33}, year = {2017}, month = {Jan-01-2017}, pages = {112 - 133}, doi = {10.1111/mms.2017.33.issue-110.1111/mms.12353}, url = {http://doi.wiley.com/10.1111/mms.2017.33.issue-1}, author = {Blevins-Manhard, Rachael and Atkinson, Shannon and Lammers, Marc} } @article {16150, title = {Different modes of acoustic communication in deep-diving short-finned pilot whales (Globicephala macrorhynchus)}, journal = {Marine Mammal Science}, volume = {33}, year = {2017}, month = {Jan-01-2017}, pages = {59 - 79}, doi = {10.1111/mms.2017.33.issue-110.1111/mms.12344}, url = {http://doi.wiley.com/10.1111/mms.2017.33.issue-1}, author = {P{\'e}rez, Jacobo Marrero and Jensen, Frants H. and Rojano-Do{\~n}ate, Laia and Aguilar de Soto, Natacha} } @article {15452, title = {Acoustic monitoring for conservation in tropical forests: examples from forest elephants}, journal = {Methods in Ecology and Evolution}, year = {2017}, month = {Jan-01-2017}, abstract = {

1. The accelerating loss of biodiversity worldwide demands effective tools for monitoring animal populations and informing conservation action. In habitats where direct observation is difficult (rain forests, oceans), or for cryptic species (shy, nocturnal), passive acoustic monitoring (PAM) provides cost-effective, unbiased data collec- tion. PAM has broad applicability in terrestrial environments, particularly tropical rain forests.


2. Using examples from studies of forest elephants in Central African rainforest,we show how PAM can be used to investigate cryptic behaviour, mechanisms of communication, estimate population size, quantify threats, and assess the efficacy of conservation strategies. We discuss the methodologies, requirements, and challenges of obtaining these data using acoustics. Where applicable, we compare these methods to more traditional approaches.


3. While PAM methods and associated analysis are maturing rapidly, mechanisms are needed for processing the dense raw data efficiently with standard computer hardware, speeding development of detection algorithms, and harnessing communication networks to move data from the field to research facilities.


4. Passive acoustic monitoring is a viable and cost-effective tool for conservation and should be incorporated in monitoring schemes much more broadly. The capability to quickly assess changes in behaviour, population size, and landscape use, simultaneously over large geographical areas, makes this approach attractive for detecting human-induced impacts and for assessing the success of conservation strategies.

}, keywords = {anthropogenic impacts, anti-poaching, bioacoustics, cryptic species, density estimate, law enforcement monitoring, Loxodonta cyclotis, passive acoustic monitoring, signal detection, SMART}, doi = {10.1111/2041-210X.12730}, url = {http://doi.wiley.com/10.1111/2041-210X.12730}, author = {Wrege, Peter H. and Rowland, Elizabeth D. and Keen, Sara and Shiu, Yu} }