Acoustic signals of a solitary subterranean rodent Ctenomys talarum (Rodentia: Ctenomyidae): physical characteristics and behavioural correlates

The purpose of this study was to analyse and describe vocalizations of a solitary subterranean rodent, Ctenomys talarum. In adult C. talarum five different sounds (four true vocalizations and one mechanical sound) were recorded during different behavioural contexts. Using data from the laboratory and literature, we classified these vocalizations as territorial, distress, and mating calls. We found that the vocalization range in C. talarum is shifted towards low frequencies, which transmit better in underground burrows and match well the hearing range described for other species of subterranean rodents. These low-frequency vocalizations, also found in other non-related subterranean rodents, may reflect an adaptation to the acoustic conditions of the habitat. Electronic Publication     

Pitch-related cues in the songs of sympatric mountain and black-capped chickadees

Acoustic frequency (pitch) cues are known to be important in the recognition of conspecific song in a number of songbird species. Mountain chickadees (Poecile gambeli) and black-capped chickadees (Poecile atricapillus) are sympatric over parts of their ranges and their species-typical songs share many features. I examined the acoustic characteristics of song of these two congeners in a region of sympatry in southern Alberta, Canada. As reported for other populations in allopatry, black-capped chickadees emphasized relative frequency cues in song production. In particular, variation in the ratios between note frequencies was significantly less than variation in the note frequencies themselves. In contrast, songs of mountain chickadees did not have constant frequency ratios and contained an introductory acoustic element absent in black-capped chickadee song. Both species may rely on song note frequency or the presence of this introductory acoustic element when differentiating between conspecific song and heterospecific song. Song measures for chickadees in sympatry were similar to measures in allopatry, providing little evidence for character displacement in song production.     

Responses to natural and synthetic phee calls by common marmosets (Callithrix jacchus)

Captive adult common marmosets (Callithrix jacchus) produce whistlelike “phee” calls in two contexts: in the home cage, where phee calls may function as part of territorial marking behavior, and when separated from social companions, where phee calls may function to reunite conspecifics. Natural and synthesized calls representing the acoustic structure of male and female calls in each context were presented to adult marmosets in a playback paradigm. Marmosets demonstrated discriminative abilities according to the context of the call and the caller's sex. Vocal and behavioral responses indicated increased vigilance and territorial behavior, following playbacks of naturally produced calls as well as synthetic calls. All animals scanned more frequently following produced calls as well as synthetic calls. All animals scanned more frequently following natural home cage as well as isolation calls, but only increased contact behavior (trills) in response to home cage calls. The responses were dimorphic according to the sex of the caller, where adult males scanned more following male calls, and adult females were more aggressive following male and female calls. The differential behavioral responses to playbacks of marmoset phee calls suggest a biological relevance to subtle differences found in the acoustic parameters of the phee call. © 1994 Wiley-Liss, Inc.

1 This article is a US Government work and, as such, in the public domain in the United States of America.

     

Infrasound in the capercaillie ( Tetrao urogallus )

We examined the sounds made by displaying male capercaillies on a lek in the Black Forest for infrasonic components. Vocalizations did not contain infrasound, whereas flutter jumps produced substantial low-frequency sound energy, with regularly spaced frequency peaks and maximum energy below 20 Hz. This pattern was found in recordings from different distances and for all tested individuals. Nonvocal infrasound may be significant in territorial behavior or orientation of capercaillie.     

Early maternal recognition of offspring vocalizations in rhesus macaques (Macaca mulatta)

This study investigated the development of maternal recognition of infant calls in rhesus macaques (Macaca mulatta). Fifteen mothers and their offspring, of age ranging from several hours to 28 days, served as subjects of an experiment in which the offspring's distress vocalizations were recorded and then played back to their mothers simultaneously with those of an age-matched control infant. The proportion of time looking at, but not the proportion of orientations to the speaker playing the offspring's vocalizations increased significantly as a function of infant age. Specifically, mothers of infants older than 1 week of age responded longer to the playback of their own infant's calls than did mothers of younger infants. These findings provide the firt evidence that offspring recognition in macaques develops between the first and second week of the infant's life and are consistent with the hypothesis that mothers need to be exposed to their infants' calls in order to learn their acoustic characteristics.     

Casomorphins reduce separation distress in chicks

Intraventricular administration of various chain length casomorphins (CM) reliably reduced separation induced distress vocalizations (DVs) in young domestic chicks. At a dose of 50 nanomoles, CM-5 was more potent than either CM-4 or CM-7, but for each the duration of action was approximately half an hour, with CM-7 having a somewhat longer effect. This suppression of DVs was partially antagonized by naloxone (1 mg/kg).     

Frequency sensitivity in the auditory periphery of male and female black-capped chickadees (Poecile atricapillus)

The black-capped chickadee is a songbird that has been used extensively as a model of animal communication in field and laboratory settings. Although many studies have focused on the complex call and song systems of the black-capped chickadee, relatively fewer studies have focused on chickadee audition. However, we do know from behavioral and molecular work that chickadees (and auditory processing areas in their brains) discriminate between artificially generated tones, between conspecific and heterospecific vocalizations, and among different types of conspecific vocalizations. In this paper we investigate peripheral auditory processing of frequency in the black-capped chickadee and the potential influence of sex on frequency sensitivity using a technique called auditory evoked potentials. We found that male and female black-capped chickadees did not differ in any measure of frequency sensitivity. Both sexes had the greatest sensitivity to frequencies between 2 and 4 kHz. This range of frequencies is well represented in black-capped chickadee song, partially supporting the idea that sender and receiver coevolve. Finally, we suggest that the call and song system of North American parids make them an ideal taxonomic group for comparative work exploring the relationship between call systems and the evolution of auditory processing.     

Mutual dependencies between vocal and visual signals of squirrel monkeys

Visually recognizable social signals and structural call components, which had been demonstrated to be of social relevance within their own communication channel in previous experiments (disregarding or experimentally excluding other ones), were treated together, and their inter-dependencies analyzed when they were performed simultaneously in spontaneous behavior sequences of pairs of adult squirrel monkeys. It was found that: (1) all call classes were uttered within periods when either genital display or “triumph gesture” were shown; (2) production rates of particular vocal classes significantly deviated from no-display periods; (3) degree and direction of deviations (more/less frequent) were quite specific for both vocal and nonvocal classes (Figs. 1a & 1b); (4) differences depended also on which animal actually displayed (the vocalizing one, the other one, or both; Fig. 3); and (5) differences found for single animals when they played different roles in the experimental situation were smaller than those found between individuals, which could be related to dominance status (Table 2). The possibility of mutual modification of signals of different modalities and perspectives for future work are discussed.     

Microevolution of eastern palaearctic Grey tits as indicated by their vocalizations (Parus [Poecile]: Paridae,Aves) I. Parus montanus: Contributions to the Fauna of the Far East,No. 2

Within the Palaearctic Region, the Willow tit (Parus montanus) displays four vicariant forms of territorial song. 1. “Alpine” form (pure single-frequency whistles, Fig. 5: 1) in the Alps and adjacent mountains to the East. 2. “Lowland” or “Normal” form (frequency change from high to low within one note, Fig. 5: 2) in the other parts of NW, Central and SE Europe. 3. In populations of N and E Europe as well as of W and E Siberia every individual bird uses - so far as known - both song types; this “Siberian” form (Figs. 1, 2) includes intergrades (Fig. 3). The comparatively type-rich Siberian repertoire is found in a vast area from N and E Europe to the Amur River and Ussuriland in Siberia. 4. In song types of S Palaearctic Asia whistled notes dominate, as in the Alpine form, but the single notes contrast by marked differences in pitch (frequency jumps); this is the “Sino-Japanese” form (Altai, China, Japan, Fig. 4). These acoustically defined groups of Eurasia comprise several morphological subspecies. Subspecies groups with the same song type are closely related. We hypothesize that the Alpine and Lowland song types developed in Pleistocene refuge areas in the southern Alps and in the Balkan Peninsula, respectively, both originating from the complex Siberian song type. According to this hypothesis, both extant Central European song types lost one note type of the Siberian song type (Lowland or Alpine, respectively). In contact zones and hybrid belts of Alpine and Lowland song, the Secondary Siberian song type occurs, which combines the Lowland and Alpine types. Marked song types, which cover vast areas, also characterize the closest relatives in the Nearctic Region, the Chickadees P. atricapillus, P. carolinensis and P. sclateri (Mexico), the most southerly representative of Chickadees in America. P. carolinensis uses Sino-Japanese song, P. atricapillus a derived form with only minor frequency jumps. The Willow tit probably evolved in the E Palaearctic Region, perhaps in the area of E China, Amur/Ussuri and NE Siberia, rich in diverse local taxa at present (songarus sector; parts of montanus sector; kamtschatkensis sector, respectively, Fig. 5). The Sino-Japanese song type was also developed here. Starting from this area, montanus settled the W Palaearctic Region, where the song types were modified as follows: loss of frequency jumps of the old Sino-Japanese form, threefold geographical splitting into areas of Alpine, Lowland and Siberian song. Also starting from NE Asia, the Nearctic Region was colonized by at least two immigration waves. The first one resulted in the present P. carolinensis, which introduced Sino-Japanese song into the Nearctic Region. Considered not closely related to P. carolinensis on genetic grounds, the present P. atricapillus may represent another immigrant from E Asia with already modified Sino-Japanese song (minor frequency jumps). In the Nearctic Region, Alpine song occurs in Alaska, where it resembles much Alpine song in Siberia and the rare Alpine form in Japan. Territorial song supports the currently rejected assumption of conspecifity of palaearctic and nearctic Willow tits under the name P. atricapillus. Despite allozyme differences, P. atricapillus and P. carolinensis behave largely as a common biological species. In accordance with its peculiar song, the allopatric P. sclateri is attributed species status. Song structure in both the montanus and atricapillus / carolinenis complexes of the Holarctic Region is highly conservative and gives even better insight into evolutionary history than morphological characters.