Behavioral Ecology of Elliot’s Laughingthrush (<Emphasis Type="Italic">Trochalopteron</Emphasis> (<Emphasis Type="Italic">Garrulax</Emphasis>) <Emphasis Type="Italic">elliotii</Emphasis>, Timaliidae,Aves): 2. Vocal Repertoire

Our work is the first study on the vocal repertoire of one of the babbler species, Elliot’s laughingthrush. Field studies were carried out in Hupingshan Nature Reserve, Hunan Province, China. There are three types of signals in the repertoire: songs, calls (chattering), and duets. Songs and calls are used by both males and females. The song consists of a quiet introduction (short note) and a louder main part (two or three tonal notes). There are up to four song variants in the repertoire of a given pair. All songs can be classified into three types. Types I and II represent songs with the main part consisting of three notes, while type III consists of two notes. Types I and II differ from each other in certain features of the frequency modulation shape of the first two notes. All song types can be used during the spontaneous vocalization of a single bird. However, their usage in other contexts differs. Songs of types I and II are more often uttered during vocal interactions of neighbor males. Songs of type III appear to be characteristic of male–female duets. Chattering (calls) is a continuous series of broadband notes. There are several (two to five) note variants in each series. Chattering can be used both during a male–female interaction and as an alarm call. We found an inverse correlation between (1) the duration of pauses between notes, and (2) the number of note variants (“repertoire size”) in a series. Both parameters probably reflect the internal state of an individual at a given moment.     

Vocal communication in a neotropical treefrog, Hyla ebraccata: Advertisement calls

We studied the vocal communication of Hyla ebraccata in central Panama. The advertisement call of this species consists of a pulsed buzz-like primary note which may be given alone or followed by 1–4 secondary click notes. Primary notes are highly stereotyped, showing little variation within or0 among individuals in dominant frequency, duration, pulse repetition rate or rise time. Males calling in isolation give mostly single-note calls. They respond to playbacks of conspecific calls by increasing calling rates and the proportion of multi-note calls, and by giving synchronized calls 140–200 ms after the stimulus begins. Responses to conspecific advertisement calls are usually given immediately after the primary note of the leading call, but the primary note of the response often overlaps with the click notes of the leading call. Experiments with synthetic signals showed that males synchronize to any type of sound of the appropriate frequency (3 kHz), regardless of the fine structure of the stimulus. Playbacks of synthetic calls of variable duration showed that males do not synchronize well to calls less than 150 ms long, but they do to longer calls (200–600 ms). The variance in response latency increased with increasing stimulus duration, but modal response times remained at around 140–200 ms. Similar results were obtained in experiments withsynthetic calls having a variable number of click notes. Males showed no tendency to increase the number of click notes in their calls in response to increasing stimulus duration or increasing number of clicks in the stimulus. Females preferred three-note to one-note calls in two-choice playback experiments, whether these were presented in alternation, or with the one-note call leading and the three-note call following. Females showed no preference for leader or follower calls when both were one-note. When two-note calls were presented with the primary note of the follower overlapping the click note of the leader, females went to calls in which click notes were not obscured. Our results indicate that male H. ebraccata respond to other males in a chorus in ways which enhance their ability to attract mates.     

Sex Differences in the Song of <Emphasis Type="Italic">Indri indri</Emphasis>

In some primate species, males and females within a social group emit loud calls in a coordinated manner or chorus. Indri indri emits a very conspicuous loud call that elicits the loud calls of neighboring groups. Previous investigations have hypothesized that the main functions of the indri chorus are related to territorial announcement, intergroup avoidance, and group cohesion. We investigated sex differences in indri song. We recorded and analysed songs given by 10 different groups over 160 d. Overall singing duration did not vary between the sexes. However, males emitted significantly fewer but longer notes. Adult males and females of each group participated in the song with sex-specific repertoires. Females had a song repertoire of 8 note types; males shared all of their 6 notes with females. Apart from the initial roars, in all note types shared by both sexes, male notes were significantly longer than female ones, whereas variations in frequency parameters differed according to the note type. These findings suggest that indri song may provide cues to conspecifics, such as group size and sex composition, which could influence interactions between groups.     

Calling,Courtship, and Condition in the Fall Field Cricket,Gryllus pennsylvanicus

Theoretically, sexual signals should provide honest information about mating benefits and many sexually reproducing species use honest signals when signalling to potential mates. Male crickets produce two types of acoustic mating signals: a long-distance mate attraction call and a short-range courtship call. We tested whether wild-caught fall field cricket (Gryllus pennsylvanicus) males in high condition (high residual mass or large body size) produce higher effort calls (in support of the honest signalling hypothesis). We also tested an alternative hypothesis, whether low condition males produce higher effort calls (in support of the terminal investment hypothesis). Several components of long-distance mate attraction calls honestly reflected male body size, with larger males producing louder mate attraction calls at lower carrier frequencies. Long-distance mate attraction chirp rate dishonestly signalled body size, with small males producing faster chirp rates. Short-range courtship calls dishonestly reflected male residual mass, as chirp rate and pulse rate were best explained by a curvilinear function of residual mass. By producing long-distance mate attraction calls and courtship calls with similar or higher effort compared to high condition males, low condition males (low residual mass or small body size) may increase their effort in current reproductive success at the expense of their future reproductive success, suggesting that not all sexual signals are honest.     

Crepuscular Changes in Emission Rate and Parameters of the Boatwhistle Advertisement Call of the Gulf Toadfish, Opsanus Beta

We quantified crepuscular variation in the emission rate and call properties of the boatwhistle advertisement call of Gulf toadfish, Opsanus beta, from a field recording of a natural population of nesting males in the Florida Keys. Their calls are more variable and complex than previously reported. A call typically starts with a grunt followed by one to five tonal boop notes (typically two or three) and lasts for over a second. The first boop is considerably longer than later ones, and intervals between boops are relatively constant until the final interval, which approximately doubles in duration. Positions of fish are fixed and calls are sufficiently variable that we could discern individual callers in field recordings. Calling rate increases after sunset when males tend to produce shorter calls with fewer notes. Analysis by number of notes per call indicates some individuals decrease the number of initial grunts and the duration of the first note, but most of the decrease results from fewer notes. To our knowledge this sort of call plasticity has not been demonstrated before in fishes. We suggest that call shortening lowers the chances of overlapping calls of other males and that the small amount of time actually spent producing sound (total on time) is an adaptation to prevent fatigue in sonic muscles adapted for speed but not endurance.     

沼水蛙繁殖期鸣声特征及鸣叫节律

鸣叫对无尾两栖类动物的生存与繁殖起重要作用。蛙类的鸣叫行为受到环境因素影响表现出一定的节律性。2016年8和9月,采用录音机和指向性话筒,在野外录制了57只沼水蛙（Hylarana guentheri）的鸣声并对其鸣声特征进行分析;通过悬挂录音笔和自动温湿度记录仪研究了沼水蛙鸣叫节律（17 d）及其与环境温度、相对湿度的关系。结果显示,沼水蛙的鸣声由1 ~ 4个音节组成,不同类型鸣声间的音节主频、音节时长存在显著差异（P < 0.05）。该物种全天具有鸣叫行为,13:00 ~ 14:00时为鸣叫高峰期。白天单音节鸣声、双音节鸣声、三音节鸣声、总鸣声和总音节的数量较夜晚显著增加（P < 0.01）。鸣声数量和音节数量均与环境温度呈正相关（P < 0.01）。结果表明,沼水蛙通过改变音节数量、音节主频和音节时长改变鸣叫策略。沼水蛙的鸣叫行为具有昼夜节律性且受环境温度的影响。     

Flexibility as a Strategy for Avoiding Call Overlap in Male Anhui Treefrogs

Male-male vocal competition is critical for mating success in anuran species; however, it remains unknown that how males regulate their competitive strategies dynamically during competition because calling is highly time-consuming, energetically demanding and likely to increase predation risks. Since different parts of calls will encode different information for vocal communication, we hypothesized that competitive strategies of male frogs may be modulated by the temporal and spectral features of different call notes. To test this hypothesis, the natural advertisement calls(OC), its modified versions with the first call note replaced by white noise(WN) or other notes and with the fifth call note replaced by WN, were played back to the Anhui tree frogs(Rhacophorus zhoukaiyae). Results showed that 1) males produced more competitive calls in response to acoustic stimuli compared to their baseline calling during silence; and 2) males emitted more non-overlapping calls compared to overlapping calls in response to the acoustic stimuli. These results are consistent with the idea that males are flexible to acoustic signals and their competition strategies are modulated dynamically by social contexts.     

Stream Noise,Hybridization, and Uncoupled Evolution of Call Traits in Two Lineages of Poison Frogs: Oophaga histrionica and Oophaga lehmanni

According to the acoustic adaptation hypothesis, communication signals are evolutionary shaped in a way that minimizes its degradation and maximizes its contrast against the background noise. To compare the importance for call divergence of acoustic adaptation and hybridization, an evolutionary force allegedly promoting phenotypic variation, we compared the mate recognition signal of two species of poison frogs (Oophaga histrionica and O. lehmanni) at five localities: two (one per species) alongside noisy streams, two away from streams, and one interspecific hybrid. We recorded the calls of 47 males and characterized the microgeographic variation in their spectral and temporal features, measuring ambient noise level, body size, and body temperature as covariates. As predicted, frogs living in noisy habitats uttered high frequency calls and, in one species, were much smaller in size. These results support a previously unconsidered role of noise on streams as a selective force promoting an increase in call frequency and pleiotropic effects in body size. Regarding hybrid frogs, their calls overlapped in the signal space with the calls of one of the parental lineages. Our data support acoustic adaptation following two evolutionary routes but do not support the presumed role of hybridization in promoting phenotypic diversity.     

Vocal and Optical Indicators of Individual Quality in a Social Seabird,the Crested Auklet (Aethia cristatella)

Indicators of individual quality in ornamentation or in vocalizations have been reported for different animal species. However, no studies have jointly investigated ornamentation and vocalizations in one species. The crested auklet (Aethia cristatella, Alcidae) is a small colonial seabird of the North Pacific and is unusual for a bird in using optical, vocal, and olfactory signals. We estimated the potential for coding individual quality in vocalizations and plumage ornamentation and the relationship between vocal and optical traits in crested auklets. During the summer seasons of 2008–2009, we recorded 359 trumpet calls from 28 individually marked males and measured indices of body size, condition, and plumage patterns of 58 male and 48 female crested auklets from a breeding colony on Talan Island, Sea of Okhotsk. We found strong interindividual differences in trumpet call characteristics. Furthermore, we found that the maximum fundamental frequency of the loudest notes of the trumpet call is negatively correlated with body condition, and head crest length is positively correlated with body size. However, we found no relationship between vocal and ornamental traits. The results suggest that advertising calls of crested auklets signal caller individuality and quality, but future experimental studies should test whether or not this is indeed case.     

Sound Spectrum Characteristics of Songs of Hainan Gibbon (Nomascus hainanus)

Gibbons are characterized by their species-specific calls, or songs. There are few studies of songs of Hainan gibbon (Nomascus hainanus). To study the sound spectrum characteristics and test for intergroup differences in Hainan gibbon song, we studied the singing behavior of Hainan gibbons in Bawangling National Nature Reserve, Hainan Province, China, intermittently from August 2002 to February 2013, collecting 184 recordings. Our results show that: 1) Hainan gibbon song bouts occur mainly 0–4 h after dawn. 2) The songs of adult males living in groups are composed mainly of one to three short notes and one to five long notes, while solitary adult male songs consist only of long frequency modulated notes and no short or single notes. 3) The song chorus is dominated by adult males, while females add a great call. Males do not have a great call, unlike those in other gibbon species. There are no female solos. 4) The sound spectrum frequency is similar in adult males living in two different groups, but the duration of the first long note differed significantly between the groups. The sonic frequencies of male and female songs are lower than those of other gibbons: no more than 2 kHz. Hainan gibbon sound structure is simple, although females participate in the chorus, reflecting their primitive status among gibbon species.     

Development of Early Vocalizations and the Chick-a-dee Call in the Black-capped Chickadee,Parus atricapillus

The chick-a-dee call of the black-capped chickadee (Parus atricapillus) is composed of discrete elements, or notes, that are combined to form hundreds of different calls. To investigate the development of this complex call, 12 families of color-marked chickadees were observed and recorded in the wild. Vocalizations were monitored for 18 d in the nest and 14–18 d postfledging. Most vocalizations of nestlings and fledglings were associated with feeding. At hatching, vocalizations consisted of a structurally simple note type that became more complex and variable with age. Around 9–12 d, the development of the call occurred, when single notes became organized into a multiple-note unit. Notes within the call differentiated into higher frequency, rapidly modulated initial note types and a lower frequency, moderately modulated terminal note type, features also present in adult chick-a-dee calls. Several adult-like calls including chick-a-dee calls, fee-bee songs, and a subsong-like vocalization developed prior to fledgling dispersal. Based on resemblances of note structure and general call structure, the chick-a-dee call appeared to develop from calls of nestlings and fledglings, although not necessarily in a chronologically linear progression. Some features of the chick-a-dee call closely resembled features of older nestling and fledgling calls, while other features more closely resembled the sounds of very young nestlings. Vocal development in the chickadee is compared with song and call development in other species, and the possible significance of acoustic resemblances between chick-a-dee calls and the food-associated calls of nestlings and fledglings is discussed.     

Intraspecific variation in advertisement call characteristics and acoustic strategies among male forest green tree frogs

Frogs are a representative taxon that use advertisement calls to aid in reproduction. In most frog species, calls vary with body size, and allometric constraints between body size and call frequency have been widely reported among anuran species. Although this variation is an important driver of sexual selection in frogs, male advertisement call strategies may also vary according to body size. In this study, we conducted playback experiments on the male forest green tree frog (Zhangixalus arboreus) to determine whether male advertisement call characteristics and strategies vary according to body size and the amplitude of intraspecific chorus noise. The results indicated that the calls of larger individuals are louder and lower than those of smaller ones, who call more frequently; moreover, the calls become lower, and the number of calls decreases, as noise levels increase. These findings suggest that forest green tree frog emits lower calls or refrains from calling when chorus noise increases, and that intraspecific variation in advertisement call characteristics can induce different strategies in response to chorus noise. Because advertisement call variation with body size is common among frog species, intraspecific variation in male advertisement call strategies may also be a common phenomenon.     

The vocal systems of two nocturnal burrowing petrels, the White-chinned Procellaria aequinoctialis and the Grey P. cinerea

I studied the calls of White-chinned Petrels Procellaria aequinoctialis and Grey Petrels P. cinerea at the Prince Edward Islands in the Southern Ocean. White-chinned Petrels gave two calls. One, the Wheezy call, was usually given from within breeding burrows, was given in response to playback of strange (= non-mate) calls, and probably served a burrow defence function. The other call, the Rattle call, was uttered roughly as often on the ground as from within the burrow. This call was mostly given by males and probably served as sexual advertisement. The one identified call type of the Grey Petrel was given in the same circumstances as the Wheezy call of the White-chinned Petrel.
In both species there was evidence of mate recognition of calls. Birds tended to remain silent to the playback of the mate's call, whereas they responded vocally to strange calls.
This vocal system, where both sexes share two call types but where sexual dimorphism in call is absent, has not been described before for petrels. Possible reasons for the variation in petrel vocal systems are discussed.     

棘胸蛙求偶鸣声与温度有关但与体大小无关

鸣声被认为是鉴别蛙类物种最有效的特征之一,但受许多因素影响。为了研究环境因素和身体大小与雄性棘胸蛙鸣声特征的关系,在人工仿生态养殖条件下测量环境温度和体温以及蛙体的大小(体重、体长),并通过个体定位,录制繁殖期中雄性棘胸蛙的求偶鸣声,分析鸣叫参数。结果表明,棘胸蛙雄性鸣声特征测量参数与体重、体长无相关性,而鸣声特征中的鸣叫时长、音节时长与环境温度、水温、体温、泄殖腔温度存在负相关性。研究结果提示在开展棘胸蛙鸣声学研究时应注意温度对其的影响。     

Syntactical Organization of the Gargle Vocalization of the Black-capped Chickadee,Parus atricapillus

The gargle is a complex call of the black-capped chickadee Parus atricapillus associated with agonistic interactions. A large sample of calls was recorded from five sites in southeastern Wisconsin. Three sites were near one another and the other two with a different dialect pattern were more distant (all sites were within 15 km of each other). A typical call consists of about 6 notes selected from an array of about 15 different note-types that are shared among individuals in the same population. Note-types are given in many combinations, and any individual may deliver many different variations. Analysis of two- and three-note sequences shows a syntactical organization with certain note-types much more likely to precede or follow than others. In some cases linkage between note-types was nearly complete. Some differences occurred among individuals and sites, but general organizational rules were similar. One effect on ordering was acoustical structure of the notes. Higher pitched, shorter duration notes were more likely at the beginning than the end of the call which often consisted of trills. Organization of the gargle was compared to that of the chick-a-dee call of the same species. Similarities include recombinant properties, general acoustic rules and syntax. A major difference may be that in chick-a-dee calls various note combinations constituting a call have different meanings, while the various note combinations comprising an individual's repertoire of gargles may be functionally equivalent.     

Female Preferences for Call Traits and Male Mating Success in the Neotropical Frog Physalaemus enesefae

Female preferences for male call traits may affect male mating success and the evolution of exaggerated secondary sexual traits. We used phonotaxis experiments to examine female preferences in the frog Physalaemus enesefae in relation to variation in male call duration, dominant frequency, intercall interval and amplitude (dB SPL). Females preferred long calls, low and average dominant frequency calls, short intercall intervals and more intense calls. We compared the patterns of female preferences with those of acoustic variation among males to test the prediction that properties with low within‐male variation are associated with stabilizing or weakly directional female preferences, whereas properties with high within‐male variation are associated with directional preferences. Females had weakly directional preferences for the dominant frequency of the call and strongly directional preferences for call duration and call rate. We also determined whether the temporal relationship between calls influenced preferences based on the dominant frequency of the call. Preferences for low‐frequency over high‐frequency calls disappeared when calls partially overlapped. Females preferred the leading call regardless of its dominant frequency. We also investigated mating patterns in the field. There was size‐assortative mating, as male and female body sizes snout‐vent length (SVL) were positively correlated. In addition, differences in the frequency distributions of body length (SVL) between mated and unmated males approached significance; lower SVL classes were underrepresented among mated males. These patterns may reflect female preferences for lower dominant frequency calls, as there is a negative correlation between male mass and the dominant frequency of the call.     

中国43种蛙类鸣声特征数据集

无尾两栖动物的鸣声通常具有物种特异性,了解其鸣声特征信息,是利用生物声学进行物种多样性调查及物种监测的前提。本文汇总、整理了2012–2020年间利用高保真录音设备在野外记录的43种(隶属于7科26属)无尾两栖动物的鸣声数据,以及相应的鸣声采集信息。对音频文件进行降噪处理后,提供了由61个鸣声的波形图及语图组成的鸣声特征数据集。本数据集展示了鸣声的多种时域和频域信息,如单音节或多音节、音节数、音节时长、音节间隔、鸣声时长、主频、基频、谐波等,为我国无尾两栖类的声学研究、物种多样性调查及鸣声监测提供了数据支持。