Les emissions sonores de Ctenodactylus gundi (Rothman) et leur signification comportementale

Calls of $\text{Ctenodactylus gundi}$ living in semi-natural conditions in our laboratory were recorded during various interactions : sexual, agonistic, maternal.The physical characteristics of the sounds lead us to describe five major structural groups and eleven vocal types. Two of them were recorded only in young animals. Intermediate calls and some complex sequences formed by association of two vocal types were observed.When emitting sounds, adult gundis can produce eight vocal sequences. In two of these phrases a constant association of two different calls can be shown. Seven sequences can be related to one of three kinds of social interactions : sexual intercourse, withdrawal or aggressivity. In each,vocal types are arranged in a gradual order based on the intensity of the interaction. The alarm call and two calls produced by young gundis when interacting with their mother must be added to the seven sequences described above.Gundi's calls appear then to be related both to the quality of social interactions and to the degree of arousal of the emitter. Functional problems are discussed and compared with available data from some other Rodents.     

Vocal communication in adult greater horseshoe bats, Rhinolophus ferrumequinum

Whereas echolocation in horseshoe bats is well studied, virtually nothing is known about characteristics and function of their communication calls. Therefore, the communication calls produced by a group of captive adult greater horseshoe bats were recorded during various social interactions in a free-flight facility. Analysis revealed that this species exhibited an amazingly rich repertoire of vocalizations varying in numerous spectro-temporal aspects. Calls were classified into 17 syllable types (ten simple syllables and seven composites). Syllables were combined into six types of simple phrases and four combination phrases. The majority of syllables had durations of more than 100 ms with multiple harmonics and fundamental frequencies usually above 20 kHz, although some of them were also audible to humans. Preliminary behavioral observations indicated that many calls were emitted during direct interaction with and in response to social calls from conspecifics without requiring physical contact. Some echolocation-like vocalizations also appeared to clearly serve a communication role. These results not only shed light upon a so far widely neglected aspect of horseshoe bat vocalizations, but also provide the basis for future studies on the neural control of the production of communicative vocalizations in contrast to the production of echolocation pulse sequences.     

Species-specific and shared features in vocal repertoires of three Eurasian ground squirrels (genus <Emphasis Type="Italic">Spermophilus</Emphasis>)

Along to alarm calls, Eurasian ground squirrels of the genus Spermophilus also produce other call types toward potential predators and rival conspecifics. Individually identified 50 speckled (Spermophilus suslicus), 18 European (S. citellus) and 59 yellow (S. fulvus) ground squirrels were examined for interspecies differences in their vocal repertoires. A separate sample of 116 (90 adult and 26 juvenile) S. suslicus was examined for presence of ultrasound in their alarm calls. In addition, all tonal calls in all the three species were checked for presence of nonlinear phenomena. Calls were elicited by approaching animals in live-traps or near burrows; some types of vocalizations were also recorded during handling. Eight call types, three tonal and five wideband ones, were described. Vocal repertoires were remarkably similar between species, excluding the alarm calls, which were species-specific. Alarm calls with ultrasonic components were found in two individuals of S. suslicus. Concerning nonlinear phenomena, biphonation in alarm calls of S. suslicus, frequency jumps and sidebands in screams of S. citellus, frequency jumps and subharmonics in screams of S. fulvus were found. Results are discussed with literature evidence on audible and ultrasonic vocalizations in ground squirrels.     

Diagnostics of nocturnal calls of Sciaena umbra (L., fam. Sciaenidae) in a nearshore Mediterranean marine reserve

Calls emitted by the brown meagre Sciaena umbra (L., fam. Sciaenidae) were recorded at the Natural Marine Reserve of Miramare (Trieste, Italy) in seven nocturnal surveys (12-h continuous sampling) during the summer of 2009. Calls consist of pulses, with the main energy content below 2 kHz and mean peak frequency of c. 270 Hz. Pulses were short, with an average duration of 20 ms and a pulse period of 100 ms. Sounds lasted approximately 500 ms. Three types of sound patterns were recognized: irregular (I), regular (R) and the chorus (C). Their acoustic parameters are described showing that I, R and C differ in pulse duration, pulse peak frequency and pulse period. Occurrence of the three call types changes throughout the night: the R pattern occurred mainly at dawn and dusk, C predominated after nightfall, while I calls were produced sporadically during the whole nocturnal period. Our results indicate that S. umbra has a pronounced nocturnal rhythm in vocalizing behaviour and highlight how the diagnostic time–frequency pattern of S. umbra calls can be used to identify the species in the field. Considering that the abundance of S. umbra is currently declining, the information presented here will be relevant in developing non-invasive and low-cost monitoring acoustic systems for managing S. umbra conservation and fishery along the Mediterranean Sea.     

Microgeographic Variation and Sharing of the Gargle Vocalization and Its Component Syllables in Black-Capped Chickadee (Aves, Paridae, Poecile atricapillus) Populations

Throughout the year during agonistic encounters, black‐capped chickadees (Poecile atricapillus) emit a vocal signal known as the gargle call. Each bird has a repertoire of structurally differing gargle calls; some are shared with others in the local area. As a basis for understanding the cultural evolution of this social signal, we initiated a study of gargle call repertoires of birds living in a narrow belt of continuous riparian habitat occupied throughout by a resident population of chickadees. During two consecutive winter seasons, we sampled repertoires at three locations over a distance of 8.4 km to quantify micro‐geographical variation. Analyses of vocal sharing and population differentiation were carried out on whole gargle calls and on the individual acoustic units (syllables) from which the whole calls are constructed. We analysed 28 380 calls of 46 subjects in the two seasons of study. Birds averaged 7.6 different calls in their gargle repertoires. Calls were composed of about 10 syllables on average. Fifty‐six different syllables were used to construct the calls of all birds. Each study site had some gargle calls unique to the local birds and some that were shared with one or both of the other two sites. There was significantly greater sharing of both calls and syllables among birds within sample sites than between sample sites. The frequencies of the different kinds of gargles and syllables were significantly correlated across the 2 yr of the study, but the correlation was stronger (r² = 0.93) for syllables than for whole gargle calls (r² = 0.61).     

Weddell seals do not lengthen calls in response to conspecific masking

Some mammalian and avian species alter their vocal communication signals to reduce masking by background noises (including conspecific calls). A preliminary study suggested that Weddell seals (Leptonychotes weddellii) increase the durations of some underwater call types when overlapped by another calling seal. The present study examined the durations and overlapping sequences of Weddell seal calls recorded in Eastern Antarctica. The calling rate, call type (13 major categories), total duration, numbers of elements per call and overlapping order of 100–200 consecutive calls per recording location were measured. In response to increased conspecific calling rates, the call durations and numbers of elements (within repeated-element call types) did not change or became shorter. Calls that were not overlapped were 3.8?±?6.1 s long, the first call in a series of overlapped calls was 14.4?±?15.7 s and subsequent calls in an overlapping series were 6.5?±?10.3 s. The mean durations of non-overlapped and overlapped calls matched random distributions. Weddell seals do not appear to be adjusting the durations or timing of their calls to purposefully avoid masking each other’s calls. The longer a call is, the more likely it is to overlap another call by chance. An implication of this is that Weddell seals may not have the behavioural flexibility to reduce masking by altering the temporal aspects of their calls or calling behaviours as background noises (natural and from shipping) increase.     

Vocal repertoire of cooperatively breeding Smooth‐billed Anis

Calls are functionally diverse signals that mediate behavior in a wide variety of contexts in both passerines and non‐passerines. However, the call‐based acoustic communication systems of non‐passerines have received less attention from investigators than those of passerines. We examined the vocal repertoire of Smooth‐billed Anis (Crotophaga ani), cooperatively breeding cuckoos that live in groups with multiple breeding pairs. We recorded calls from 22 groups over two breeding seasons at the Cabo Rojo National Wildlife Refuge in Puerto Rico. We identified 11 call types and one group vocalization, and used an automated sound measurement program to quantify their acoustic features. Discriminant function analysis (DFA) correctly classified 74.2% of calls based on these features. The vocal repertoire of Smooth‐billed Anis is larger than that reported for the three other species in the subfamily Crotophaginae. Smooth‐billed Anis have at least two alarm calls, two nest‐specific calls, and one nest defense call. We also identified one possible signal of aggressive intent, one possible appeasement signal, and two calls that may communicate identity. The relatively large vocal repertoire of Smooth‐billed Anis and association of distinct call types with different functions and contexts supports the main prediction of the social complexity hypothesis, i.e., species with more complex social systems will have more complex communication systems.     

Golden-marmot Alarm Calls. II. Asymmetrical Production and Perception of Situationally Specific Vocalizations?

Many species produce alarm calls that vary according to situation. An implicit assumption for these species is that production and perception of situationally specific alarm calls is symmetrical: perceivers respond to variation produced by signalers. The companion paper to this one (Blumstein 1995) showed that golden marmots (Marmota caudata aurea) produce variable alarm calls that vary in proportion to the degree of risk the caller perceives. Calls produced in higher-risk situations have fewer notes than calls produced in lower-risk situations. In this study, to determine the salience of the number of notes per call in eliciting different responses in conspecific perceivers, I played back three-note alarm calls, eight-note alarm calls, and the non-alarm vocalization of a local bird to adult golden marmots. Although marmots responded differently to bird calls and alarm calls, vigilance responses to the different alarm calls were similar. Several explanations may account for the apparent insensitivity to alarm-call variation: golden marmots may require additional contextual cues to properly interpret alarm calls, perceptual abilities do not parallel production abilities, or calls may serve a generalized alerting function.     

Substrate-gleaning versus aerial-hawking: plasticity in the foraging and echolocation behaviour of the long-eared bat,Myotis evotis

The foraging and echolocation behaviour of Myotis evotis was investigated during substrate-gleaning and aerial-hawking attacks. Bats gleaned moths from both the ground and a bark-covered trellis, however, they were equally adept at capturing flying moths. The calls emitted by M. evotis during substrate-gleaning sequences were short, broadband, and frequency-modulated (FM). Three behavioural phases were identified: search, hover, and attack. Gleaning search calls were significantly longer in duration, lower in highest frequency, and larger in bandwidth than hover/attack calls. Calls were detected in only 68% of gleaning sequences, and when they were emitted, bats ceased calling 200 ms before attacking. Terminal feeding buzzes, the rapid increase in pulse repetition rate associated with an attempted prey capture, were never recorded during gleaning attacks. The echolocation calls uttered by M. evotis during aerial-hawking foraging sequences were also short duration, high frequency, FM calls. Two distinct acoustic phases were identified: approach and terminal. Approach calls were significantly different from terminal calls in all variables measured. Calls were detected in 100% of aerial-hawking attacks and terminal feeding buzzes were invariably produced. Gleaning hover/attack calls were spectrally similar to aerial approach calls, but were shorter in duration and emitted at a significantly lower (but constant) repetition rate than aerial signals. Although the foraging environment (flight cage contents) remained unchanged between tasks (substrate-gleaning vs. aerial-hawking), bats emitted significantly lower amplitude calls while gleaning. We conclude that M. evotis adjusts its echolocation behaviour to meet the perceptual demands (acoustical constraints) imposed by each foraging situations.Abbreviations BW bandwidth - CF constant frequency - dB SPL decibels sound pressure level - FM frequency modulated - HF highest frequency - LF lowest frequency - PF peak frequency Presented at the meeting Acoustic Images in Bat Sonar, a conference on FM echolocation honoring Donald R. Griffin's contributions to experimental biology (June 14–16, Brown University, Providence RI).     

CALL ANALYSIS OF TRIPLOID HYBRIDS RESULTING FROM DIPLOID-TETRAPLOID SPECIES CROSSES OF HYLID TREE FROGS

ABSTRACT

Calls produced by hybrids resulting from laboratory crosses of tetraploid Hyla versicolor females and either diploid Hyla chrysoscelis (type I) or Hyla arborea (type II) males were induced through manipulation of environmental conditions. Type I hybrids produced trilled calls similar in note repetition to H. versicolor, but more similar in dominant frequency to H. chrysoscelis. Mean duration was shorter than in both parent calls. Type II hybrids produced calls which were longer in duration and lower in note repetition rate than H. versicolor, but shorter in duration and higher in note repetition rate than H. arborea. Dominant frequency of type II hybrids was lower than in H. arborea but not significantly different than in H. versicolor. Hybrid calls were not strictly intermediate, and may provide information regarding parental relationships.     

THE SIGNIFICANCE OF MULTI-NOTE ADVERTISEMENT CALLS IN A REED FROG,HYPEROLIUS TUBERILING UIS

ABSTRACT

The reed frog Hyperolius tuberilinguis is a prolonged breeder with an advertisement call that varies in complexity from one to six click notes. Call complexity increases with chorus size, but calls containing more than three notes are rare. In playback experiments to males, subjects responded by increasing the complexity of their calls, without closely matching the stimulus and rarely exceeding the stimulus in complexity. Stimuli less complex than their own evoked a reduction in complexity. Call repetition rate remained unchanged in the responses. In two-choice phonotaxis experiments, females discriminated against one-note calls, and two- and three-note calls were the most attractive. Males thus adjust their calling in the presence of neighbours to a pattern most preferred by females. Calls of higher complexity may be more easily detected or located by females in the noisy environment of a chorus.     

An Analysis of the Organization of Vocal Communication in the Titi Monkey Callicebus moloch

Vocalizations of titi monkeys were recorded from 6 groups at two sites in the llanos of Colombia during 8 months of study. Frequency and temporal measurements from spectrograms of recordings, and differences in their patterns of use, were used to characterize call types. Animals repeat calls to form phrases, and combine phrases to form sequences. The six sequence types, defined by different transition probabilities between phrases, varied in proportion in different contexts. To examine the effect of order of phrases on response, I played back artificially constructed sequences to subject groups. I discuss hierarchical and sequential mechanisms as generators' of vocal sequences, and draw comparisons with models of human language.     

Production and perception of sex differences in vocalizations of Wied's black‐tufted‐ear marmosets (Callithrix kuhlii)

Males and females from many species produce distinct acoustic variations of functionally identical call types. Social behavior may be primed by sex‐specific variation in acoustic features of calls. We present a series of acoustic analyses and playback experiments as methods for investigating this subject. Acoustic parameters of phee calls produced by Wied's black‐tufted‐ear marmosets (Callithrix kuhlii) were analyzed for sex differences. Discriminant function analyses showed that calls contained sufficient acoustic variation to predict the sex of the caller. Several frequency variables differed significantly between the sexes. Natural and synthesized calls were presented to male–female pairs. Calls elicited differential behavioral responses based on the sex of the caller. Marmosets became significantly more vigilant following the playback of male phee calls (both natural and synthetic) than following female phee calls. In a second playback experiment, synthesized calls were modified by independently manipulating three parameters that were known to differ between the sexes (low‐, peak‐, and end‐frequency). When end‐frequency‐modified calls were presented, responsiveness was differentiable by sex of caller but did not differ from responses to natural calls. This suggests that marmosets did not use end‐frequency to determine the sex of the caller. Manipulation of peak‐and low‐frequency parameters eliminated the discrete behavioral responses to male and female calls. Together, these parameters may be important features that encode for the sex‐specific signal. Recognition of sex by acoustic cues seems to be a multivariate process that depends on the congruency of acoustic features. Am. J. Primatol. 71:324–332, 2009. © 2008 Wiley‐Liss, Inc.     

Within-pod variation in the sound production of a pod of killer whales, Orcinus orca

Pod-specific calling behaviour of resident killer whales has been shown to include: discrete call types not shared among pods, different production rates of shared call types, and differences in the detailed structure of shared call types. To investigate the mechanisms leading to pod-specific calling, we compared the repertoire and structure of calls produced by three different matrilineal units within the same pod, and described call features encoding matrilineal-unit distinctiveness. The three matrilineal units had different production rates of shared calls, including one call type used almost exclusively by one matrilineal unit. Cross-validated discriminant function analyses revealed matrilineal-unit distinctive structure in five of the six shared call types examined, with duration of the terminal component being the most distinctive feature for all call types containing a terminal component. Calls generally consist of low- and high-frequency components that may follow different time-frequency contours. In our sample, a particular high-frequency contour was consistently paired with a particular low-frequency contour, both contours had roughly equal overall variability, and each contained independent matrilineal-unit distinctive information. The only call type that did not differ structurally between matrilineal units is reportedly used more in interpod meetings than in intrapod contexts. The differences in calling behaviour between matrilineal units were similar in form to previously described differences between pods, although more subtle. These results suggest that pod-specific calling behaviour in resident killer whales arises primarily as a consequence of accumulated drift or divergence between highly cohesive matrilineal units as they gradually separate into different pods. Copyright 2000 The Association for the Study of Animal Behaviour.     

Vocalizations of Australian hopping mice (Rodentia: Notomys)

The four species of hopping mouse studied, N. alexis, N. cervinus, N. fuscus and N. mitchellii , were found to have a basic repertoire of eight more or less discrete vocalizations: three in the young—the calls produced in the nest, ultrasonic pipping given when removed from the nest and a high intensity (pain) squeal—and five in the adult—a low intensity pip given during mutual grooming, a high intensity (pain) squeal, a medium intensity squeak given when "annoyed", twittering given during aggressive chases and ultrasonic pipping given during non-aggressive encounters. The calls of the different species varied in structure and in pitch. No vocalizations were associated with threat or fighting. Calls given in the nest by suckling young are well developed and the intensity of such calls appears to mirror the general motivational state of the caller. It is suggested that these calls may act to maintain maternal behaviour in the mother.     

Kea Nestor notabilis mothers produce nest-specific calls with low amplitude and high entropy

Vocal behaviour of nesting altricial birds is subject to selection pressure from several sources. Offspring beg to attract parents’ attention, thus increasing the chances of being fed, but also increasing the chances of being detected by predators. Research on passerines has shown that parents may reduce the risk of nest predation by alarm calling to warn nestlings to be quiet, and by producing food calls which solicit begging when parents are present to defend the nestlings. Both nestlings and parents may reduce the risk of predator detection by producing calls of low amplitude and high entropy which are acoustically difficult to locate. Although extensive research has been undertaken on nesting passerine vocalizations, little is known about parrots in this regard, and studies are needed to determine whether parrots show similar adaptations. We investigated the calling behaviour of Kea Nestor notabilis mothers during the nesting period to determine whether maternal vocalizations were adapted in a way that could increase the chance of brood success. A microphone was installed inside the nest to record calls produced both inside the nest and in the direct vicinity. Our prediction was that calls outside the nest would be easy to locate and could function as alarm calls to alert conspecifics or distract the predator, whereas calls inside the nest would be difficult to locate and could serve to communicate with nestlings without alerting predators. Our results accorded with these predictions. Calls produced outside the nest were loud and tonal, and corresponded to previously described Kea alarm calls. Calls produced inside the nest, however, were high-entropy and low-amplitude calls, and formed a distinct structural category. We thus provide the first evidence that a parrot species has a vocal category for communication inside the nest, and that calls within this category are structured in a way that could reduce the risk of nest predation.     

Variability in blue whale acoustic behavior off southern California

To evaluate the acoustic behavior of blue whales (Balaenoptera musculus) located inshore and offshore of southern California, singular A and B calls, D calls, and AB phrases were analyzed from 12 mo of passive acoustic data collected at four locations within the Southern California Bight. The relative proportions of singular calls and phrases were used to evaluate spatial and temporal patterns in sound and song type usage, and singular call and phrase production rates were calculated to investigate spatial and temporal variability in call abundance. Blue whale sounds were recorded from spring through early winter, with the majority of all detections occurring between September and December. The proportions and production rates of singular calls and phrases varied between the inshore and offshore sites. In addition, the percentage of A units within repetitive song phrases was greater inshore than offshore, resulting from a higher proportion of AB song type inshore, in which A and B phrase units were alternating. The ABB song type, in which a single A unit was followed by multiple B units, was more common offshore. The observed differences in calling and singing behaviors may identify distinct and variable acoustic behavioral settings for blue whales off southern California.     

Vocal signals fromCtenomys pearsoni pups

Calls emitted by newborn pups ofCtenomys pearsoni Lessa and Langguth, 1983 away from the nest were frequency modulated succesive notes. The notes were characterized by mean maximum frequency under 5165 Hz, with mean main frequency under 2155 Hz, and mean note duration under 0.165 s. Their possible function as contact or distress calls, resulting in recovering to the nest by the mother, is discussed.