VOCAL ONTOGENY OF NESTLING AND FLEDGLING BLACK-CAPPED CHICKADEES POECILE ATRICAPILLA IN NATURAL POPULATIONS

ABSTRACT

We studied the vocal ontogeny of black-capped chickadees Poecile atricapilla from hatching through approximately age 40 days, at which time the juveniles dispersed from their hatching area. Development of three vocalisations (chick-a-dee call, fee-bee song, gargle call) was monitored by tape recording daily. Spectrographs quantification and comparison were carried out with Sound Analysis software. Developmental changes in offspring vocalisations were compared to the parent birds, allowing a measure of acoustic similarity between adults and young throughout early life. The chick-a-dee call developed all four of its component syllables (ABCD) from a single sound of day-old nestlings, but the four syllables emerged in adult form at different times in ontogeny. The fee-bee song was produced in impressively adult form starting at about age 20 days, with no precursor sounds to indicate gradual emergence. The principal difference between adult and juvenile fee-bee songs was the persistent production of three or four notes by juveniles rather than the adults' species-typical two notes. Gargle calls appear to develop from “subsong” strings of precursor gargle syllables. Juvenile gargles began to be identifiable at about age 33–35 days but did not match any of the gargle calls of the local adult population. Post-dispersal juveniles may develop gargles that match the gargle types of local birds where they settle.     

VOCAL BEHAVIOUR AND CALL DEVELOPMENT IN THE BULLFINCH (PYRRHULA PYRRHULA)

ABSTRACT

A sonagraphic analysis of the vocalizations of bullfinches Pyrrhula pyrrhula is presented and their behavioural contexts and functions noted. The vocal repertoire of the bullfinch is compared to that of other finches with particular attention to repertoire size and sexual specificity; the repertoire of 14–17 vocal categories is comparatively greater than that of most carduelines and the majority of vocalizations were given by both sexes. The development of nestling, fledgling and some adult calls is described. Early vocal ontogeny in the bullfinch was similar to that previously described for the chaffinch. The earliest recorded calls of nestling bullfinches showed a single fundamental. The independent use of two sound sources became apparent on the second day after hatching and the major elements of the three best studied call types were all derived from the lower fundamental of the nestling begging call.     

Age differences and developmental trends in alarm peep responses by squirrel monkeys (Saimiri sciureus)

Alarm calls can code for different classes of predators or different types of predatory threat. Acoustic information can also encode the urgency of threat through variations in acoustic features within specific alarm call types. Squirrel monkeys (Saimiri sciureus) produce an alarm call, known as the alarm peep, in highly threatening situations. Infant squirrel monkeys appear to have an innate predisposition to respond to alarm peeps but require experience to associate alarm peeps with the appropriate type of predatory threat [Herzog & Hopf, American Journal of Primatology 7:99-106, 1984]. Little is known about age-related differences in the type or frequency of response to alarm peeps, or the development of alarm peep response in infants. The purpose of this study was to test experimentally the response strategies of different age classes of squirrel monkey to the playback of alarm peeps that were produced by infants, juveniles, or adults. Results suggest that infants, juveniles, and female subadults respond more frequently to alarm peeps than do adult females. Infant squirrel monkeys showed different behavioral strategies in response to alarm peeps as a function of age. Adult females differentiate between infant and adult alarm peeps by responding more frequently to the alarm peeps of adult females. These data demonstrate that squirrel monkeys use acoustic information to discern when to respond to the alarm peeps from conspecifics, and that infants gradually develop an adult-like response to alarm peeps over the first year of development.     

Vocal repertoire ontogeny of the captive Asian house shrew Suncus murinus suggests that the male courtship call develops from the caravanning call of the young

Soricids produce a considerable variety of vocalizations. However, these calls have been studied insufficiently with the exception of echolocation calls. In this study, 1,645 calls from 18 juvenile, ten sub-adult and 36 adult Asian house shrews (Suncus murinus) were acoustically and statistically analyzed to describe this species’ vocal repertoire and its ontogeny. The vocal repertoire of S. murinus includes 17 call types, seven tonal (whistle, chirp, twitter, whimper, squeak, scream and short scream) and ten non-tonal (churr, shriek, babble, click, boom, snort, screech, short screech, sniff and low click), of which ten call types (whimper, squeak, scream, short scream, churr, babble, snort, short screech, sniff and low click) were newly described by this study. This relatively extensive vocal repertoire, including one call type emitted during collective resting, indicates that this species possibly possesses a higher degree of sociality and cohesiveness than previously expected. High structural similarities were observed between calls produced by juveniles and sub-adults during caravanning and those produced by adult males during courtship. Therefore, the results of this study support a previously suggested hypothesis that in shrews, adult courtship calls are derived from calls emitted by the young. The results of this study also showed that the largest changes in the ontogeny of the vocal repertoire occurred at approximately 10 days old and was in close connection to the eyes opening. The results are discussed with available information on the vocal repertoires of other soricids.     

Ontogeny of behavior of hand-reared and hen-reared captive houbara bustards

The ontogeny of behavior of hand-reared and hen-reared captive houbara bustards (Chlamydotis undulata) was recorded between hatching and fledging and compared to determine ways to improve the behavioral and physiological health of individuals destined for release into the wild. Chicks from both groups were able to walk and run on the first day after hatching, although they were least active during the first 5 days. Thereafter, time spent prone with the head down, in a half-crouch position (resting on the tarsi) or being brooded during the day (in the case of hen-reared chicks), decreased quickly, and time spent walking and standing increased. Pecking and some preening and comfort behaviors were expressed from the first day in both groups, but increased after ˜15 days. Simple threat displays were first expressed at 6 days in both groups, but developed into more complete displays with age. The only differences found between the two rearing techniques were in time spent walking and in the half-crouch position: hen-reared chicks spent more time walking and less time in a half-crouch position than hand-reared chicks, because the hen stimulates the chicks to move. Lack of exercise during growth may result in poor development of locomotive structures, which may compromise the survival of chicks destined to be released to the wild. However, hand-reared juveniles were equally likely to survive as hen-reared juveniles after being released, suggesting that hen- rearing by captive-bred birds in a confined and artificial environment did not confer appreciable advantages. Zoo Biol 17:245–255, 1998. © 1998 Wiley-Liss, Inc.     

Parent-offspring recognition in bank swallows (Riparia riparia): II. Development and acoustic basis

In study 1, bank swallow (Riparia riparia) chicks were exchanged with like-aged chicks from other broods. Parents accepted chicks that were transferred into their nests at age 15 days or younger; rejection began to occur at 16 to 17 days. In study 2, chicks' vocalizations were recorded in the burrow. We found that an immature begging call given by young chicks is replaced by a ‘signature’ call at 15 to 17 days of age. An acoustic analysis suggested that these calls are individually distinctive. Study 3 was a playback experiment designed to test whether the chicks' signature calls are a sufficient cue for parental recognition. We found that parents would approach a speaker broadcasting the calls of their chicks in preference to one simultaneously broadcasting the calls of alien chicks. The pattern of results suggests that parental recognition is based on the chicks' signature calls and that development of recognition is dependent on the development of the call.     

Differences in distress: Variance and production of American Crocodile (Crocodylus acutus) distress calls in Belize

Acoustic communication of American Crocodiles (Crocodylus acutus) is relatively understudied. Our overall aim was to determine the acoustic structure of wild American Crocodile distress calls, distinguish call differences among size classes (hatchling, juvenile, sub‐adult, and adult), and investigate call production on a gradient of human disturbance. American Crocodile distress calls have strong frequency modulation and are comprised of multiple harmonics in a downsweeping pattern. Measured parameters (total duration, first quartile duration, maximal frequency, first quartile frequency, end frequency, slope of first quartile, slope of last quartiles) differed significantly among size classes (p < .05). Hatchling distress calls are higher in frequency and strongly modulated, whereas calls produced by sub‐adults and adults showed little modulation, are lower in frequency, and have greater overall duration. Proportion of crocodiles that produced distress calls during capture differed by size class and sampling location, particularly adult distress calls which are reported here to be produced with undocumented frequency. We determined that American Crocodiles of all size classes produce distress calls at varying rates among study sites. Our results demonstrate that American crocodiles produce distress call more frequently at sites with higher anthropogenic activity. Measured call parameters of juveniles and hatchling American crocodiles also varied among sites in relation to human disturbance. Calls recorded at sites of high anthropogenic impact have increased duration and less modulation which may adversely affect response to emitted distress calls. Proportional and call parameter variances suggest anthropogenic activity as a driver for increased call production and alteration of call parameters at high human‐impacted sites.     

Sibling Recognition in Bank Swallows (Riparia riparia)

Observations of the behavior of newly-fledged bank swallows suggest that sibling recognition may be a mechanism promoting location of the home burrow in their large, dense colonies and of cohesion of family groups following departure from the burrow. We tested for sibling recognition in the field by comparing the antiphonal response of sibling groups to the recorded calls of own vs. unrelated sibling groups. Birds responded more to the calls of their own groups. In a laboratory experiment we raised chicks in isolation from 8–10 to 20 days of age and exposed them to a call of an unrelated chick. When tested in a choice situation at 15–20 days, chicks approached the familiar call in preference to a different call which they had not previously heard. We suggest that sibling recognition is based on familiarity, i.e., that it requires a period in which the calls of siblings are learned.     

Age- and sex-dependent contact call usage in Japanese macaques

The question of the flexibility of nonhuman primate vocal communication remains open today, especially due to early evidence of innately guided vocal production. However, socially determined flexibility can be found when the debate is moved from vocal structure to vocal usage. While increasing evidence shows that the audience quality influences the vocal behaviour of nonhuman primates, the impact of the caller’s characteristics has been far less studied. Here, we tested the influence of an individual’s sex and age on the usage style of contact calls. We recorded contact calls of male and female Japanese macaques and compared the vocal usage styles of approximately 1-year-old juveniles with those of adults at various ages. We found, first, important differences in call usage style between juveniles and adults, the latter forming temporally ruled vocal exchanges respecting an interindividual turntaking principle. Moreover, sex differences were substantial in adults but nonexistent in juveniles. Finally, age continued to influence female vocal behaviour during adulthood, whereas dominance rank explained differences between adult males. Two nonexclusive mechanisms can explain this phenomenon, that is, a socially guided development of the appropriate form of calling versus an emotional maturation to control call emission, opening new lines of research on nonhuman primate vocal development of appropriate usages.     

Observations on the breeding biology and behaviour of the Lesser Jacana,Microparra capensis

Two Lesser Jacana nests were found in Hwange National Park, Zimbabwe and were observed over a period of four months beginning in March 2000. Both sexes were involved in preparing the breeding platform, incubation, and caring for the chicks, which were not carried by the adults. Both nests had three eggs. The incubation period for one clutch of eggs was not less than 19 days. The chicks all hatched on the same day and remained in the vicinity ofthe nest for the first few days where they were brooded by an adult. Initially the adults brought food to the chicks but the chicks started feeding themselves when they moved away from the nest. Ten days after hatching the chicks had doubled in size and were walking confidently with the attending adult some distance from the nest. First flight was seen at 32 days old, and the chicks appeared to be independent 63 days after hatching.     

The response of willow grouse chicks to auditory stimuli 2. Synthesized brooding calls attract machine-incubated chicks

Willow grouse (Lagopus l. lagopus) chicks appear to possess a ‘template’ of the hen's brooding call. Chicks newly hatched from machine-incubated eggs were therefore exposed to a number of electronically synthesized approximations to brooding calls. These sounds were either paired with a recording of a grouse hen's brooding call, or were played alone. Some of the synthesized calls (repetitive, low-frequency) attracted chicks, while others appeared to be aversive. None of the synthesized calls drew chicks away from the recorded hen call. These results suggest that grouse chicks will approach a wide range of attraction calls which have certain minimum features.     

On the responses of laughing gull chicks (Larus atricilla) to the calls of adults II. Age changes and responses to different types of call

Three age-groups of laughing gull chicks were tested with playback of recordings of calls of their parents and calls of neighbouring adults. The chicks in each group showed response to the playback calls, and recognition of the voices of their parents. The chicks in the early group (1 to 3 days post-hatching) showed the least evidence of parent recognition: the chicks of the late group (12 to 28 days post-hatching) showed the lowest levels of response in general.Evidence of relationships between variation in the behaviour in the tests and variation in the test recordings was found from correlation analysis, the type of call initiating positive response, and analysis of temporal association. This evidence, and the results of tests which allowed responses to the parents' crooning and responses to the parents' ke-hah calls to be compared for chicks in the late group, indicate that whereas the filial approach behaviour of very young chicks is stimulated by crooning but suppressed by ke-hah and long-calls, this behaviour in older chicks requires the occurrence of ke-hah calls or long-calls for its elicitation. However the ke-hah calls and long-calls of adults other than the parents continue to have negative effects on the behaviour of older chicks.It is argued that this progression in discrimination of the voices of the parents and the changes in responsiveness to the different types of adult calls are consistent with functional requirements, both from the point of view of changes in a growing chick's social situation and from the point of view of the characteristics of the calls. The changes are also discussed from a developmental point of view.     

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.     

CLASSIFICATION OF DIVERSE CALL TYPES USING CLUSTER ANALYSIS TECHNIQUES

ABSTRACT

We investigated the problem of categorizing the repertoire of a group of highly varied vocalizations. A set of Weddell seal Leptonychotes weddellim-air calls recorded near Davis, Antarctica, were examined. The repertoire size was estimated by first subjectively assigning each call (based on auditory and spectrographic patterns) to one of a large number of provisional call types. A set of frequency, duration and waveform measurements were made on every call. For each provisional call type, the mean value of each of these measures was calculated. These mean values were used to perform Cluster Analyses of the provisional call types. Beginning with calls clustered closest together, the most similar provisional call types were successively amalgamated until further joining would link two clearly dissimilar vocalizations (rising versus falling frequency sweeps in this case). The Weddell seal repertoire contained 12 call types ranging from long sinusoidal upsweeps to growls. This procedure provides a method of estimating the minimum repertoire size of a sample of calls. Dichotomous Sorting using Principal Components Analysis can also be used to categorize calls but will probably be of greater value when applied to finding subdivisions within a single call type.     

The influence of age and sex on the vocal repertoire of the Antillean manatee (Trichechus manatus manatus) and their responses to call playback

Limited information is available regarding the acoustic communication of Antillean manatees, however, studies have shown that other manatee taxa produce vocalizations as a method of individual recognition and communication. Here, the acoustic signals of 15 Antillean manatees in captivity were recorded, aiming to (1) describe their acoustic repertoire, (2) investigate the influence of sex and age on vocalization, and (3) examine manatee responses to call playback. Six acoustic signals ranging in mean fundamental frequencies from 0.64 kHz to 5.23 kHz were identified: squeaks and screeches were common to adult males, adult females, and juveniles; trills were common to adult males and females; whines were specific to males; creaks were specific to females; and rubbing was specific to juveniles. The structure of squeak vocalizations was significantly different between age and sex classes and screech structure was significantly different between age classes. Squeaks and screeches produced by juveniles had higher frequencies of maximum energy when compared to those produced by adult males and females. A significant increase in the vocalization rate following vocalization playbacks was found for all three age/sex groups. Our results introduce the potential of using acoustic signals in identifying and noninvasively monitoring manatees in the wild in Brazil.     

Intimate social behavior in infant interactions in Cebus apella

The development and individual stability of three intimate social behaviors (Lipsmacking, Carrying Attempts, and Facial Inspection) were examined for 43 group-housed Cebus apella infants from birth to 2 years of age. Occurrence of these behaviors was scored from 10-min videotape samples recorded three times a week over that time. Frequency of Lipsmacking and Carrying Attempts by adult males, adult females, and juveniles were all highest in early months and decreased to low levels by the end of the first year. Facial Inspection of partners by infants, in contrast, first began at 3-4 months and increased over time, at least to adult males and juveniles. Correlational analyses indicated stable individual differences in these interactions with infants and outlined a relationship between these intimate behaviors and more general social patterns reported previously for these animals. Results suggest that adult males may play a special role in affording juveniles opportunities for social learning of foraging and manipulative skills.     

牡丹鹦鹉(Psittacula agapornis)的鸣声发育

牡丹鹦鹉的鸣声发育分为5个时期。0￣12d为先天性鸣声期,鸣声特征为以基本音(BS)为主音的单音节单音调声,声长短。13￣30d为空白模板形成期,鸣声特征为以基本音为主音的多音节单音调声,声长和音量显著性增加,表明发声学习通路开始形成。31￣45d为鸣声模板形成期,鸣声特征为以第1陪音(UP)1为主音的多音节单变调声,声长和音量显著性增加,主音频提升约920音分,涵盖的律音数增加1倍,表明发声学习模板逐渐形成,发声学习开始。46￣90 d为鸣声反馈学习期,鸣声特征为以BS和UP1为主音的双变调声,声长和音量显著性增加,主音频涵盖的律音数增加2.6￣3.0倍,第2主音频提升约970音分,表明稳定模板逐渐形成,短期记忆逐渐向长期记忆转化。91d后为完美鸣声期,鸣声特征为以UP1为主音的复合变音调声,声长、音量、主音频的提升和涵盖的律音数都趋于平稳,鸣声稳定而和谐,表明发声运动通路基本形成。这些结果可为进一步揭示鸟类发声学习记忆机制提供直接的声学证据。