@article {53425, title = {An evaluation of the efficiency of passive acoustic monitoring in detecting deer and primates in comparison with camera traps}, journal = {Ecological Indicators}, volume = {98}, year = {2019}, month = {Jan-03-2019}, pages = {753 - 762}, abstract = {

In recent years, camera traps have rapidly become popular for the large-scale monitoring of wildlife distributionand population; however, we should not ignore the uncertainty regarding the reliability of camera-basedmonitoring by inexperienced data gatherers. This study introduces passive acoustic monitoring (PAM) as aneasier technique for monitoring terrestrial mammals that uses the sound cues that they produce. To validate theefficacy of PAM, we quantitatively compared the detection areas and rates between sound cues (from PAM) andvisual cues (from camera traps) of two mammals\—the sika deerCervus nipponand the Japanese macaqueMacacafuscata\—across seven study sites in eastern Japan with different population densities. To collect sound cues, weset up multiple autonomous recording units at the sites and continuously recorded ambient sounds, following apre-determined schedule. The total recording time reached 9081 h for deer and 8235 h for macaques. We thenbuilt sound recognizers to automatically detect eight target call types from the recorded data. To collect visualcues, we also set multiple camera traps at the same sites and for the same observation periods. The keyfindingswere as follows: (1) the fully automated procedures that only used the recognizers to detect sound cues producednumerous false positive detections when the call type possessed vocal plasticity and variations; (2) the semi-automated procedures, which included an additional step to validate the automated detections by manualscreening, exhibited a great improvement in the detectability and recall rates of the half of the target calls,reaching \> 0.70; (3) when using the semi-automated procedures, the frequency of deer and macaque detectionsper trap-day derived from the sound cues were in most cases approximately dozens of times and several times,respectively, higher than that derived from the visual cues; (4) the main advantage of PAM may be its superiordetection areas, which were 100\–7000 times wider than those of camera traps; and (5) the current success of therecognition of different call types of each species could broaden the use of PAM, which is not possible for cameratraps. PAM could provide socio-behavioral data (i.e., the frequencies and types of inter-individual vocal com-munications) that could help understand the status of population dynamics and the group compositions, inaddition to information related to the presence or absence of species.

}, keywords = {Cervus nippon, Ecoacoustic monitoring, Lag-phase management, Macaca fuscata, passive acoustic monitoring}, issn = {1470160X}, doi = {10.1016/j.ecolind.2018.11.062}, url = {https://linkinghub.elsevier.com/retrieve/pii/S1470160X18309257https://api.elsevier.com/content/article/PII:S1470160X18309257?httpAccept=text/xmlhttps://api.elsevier.com/content/article/PII:S1470160X18309257?httpAccept=text/plain}, author = {Enari, Hiroto and Enari, Haruka S. and Okuda, Kei and Maruyama, Tetsuya and Okuda, Kana N.} } @article {53243, title = {Temporal adjustment of short calls according to a partner during vocal turn-taking in Japanese macaques}, journal = {Current Zoology}, year = {2018}, month = {Mar-10-2019}, abstract = {

Turn-taking is a common feature in human speech, and is also seen in the communication of other primate species. However, evidence of turn-taking in vocal exchanges within a short time frame is still scarce in nonhuman primates. This study investigated whether dynamic adjustment during turn-taking in short calls exists in Japanese macaques Macaca fuscata. We observed exchanges of short calls such as grunts, girneys, and short, low coos during social interactions in a free-ranging group of Japanese macaques. We found that the median gap between the turns of two callers was 250\ ms. Call intervals varied among individuals, suggesting that call intervals were not fixed among individuals. Solo call intervals were shorter than call intervals interrupted by responses from partners (i.e., exchanges) and longer than those between the partner\’s reply and the reply to that call, indicating that the monkeys did not just repeat calls at certain intervals irrespective of the social situation. The differences in call intervals during exchanged and solo call sequences were explained by the response interval of the partner, suggesting an adjustment of call timing according to the tempo of the partner\’s call utterance. These findings suggest that monkeys display dynamic temporal adjustment in a short time window, which is comparable to turn-taking in human speech.

}, keywords = {primate, rhythm, turn-taking, vocalization}, issn = {1674-5507}, doi = {10.1093/cz/zoy077}, url = {https://academic.oup.com/cz/advance-article/doi/10.1093/cz/zoy077/5132690}, author = {Katsu, Noriko and Yamada, Kazunori and Okanoya, Kazuo and Nakamichi, Masayuki} } @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} }