Playback Interactions with Great Crested Flycatchers,Myiarchus crinitus (Aves,Tyrannidae)

Interactive playback was used to test observational findings that different vocalizations uttered by singing great crested flycatchers, Myiarchus crinitus (Aves, Tyrannidae), each provide distinctive information about behavior. We present the results of these tests and interpret their significance in combination with the observations. The following predictions were confirmed: 1. Few weep or weeuh songs, and no thrr, were uttered by subjects that approached playback; 2. Churr, common during observations of more active and changing behavior, often predominated during subjects' initial approaches and searches for simulated intruders; 3. Churr was succeeded by wit, which had been found during confrontational behavior, and weihp, which came with movement near opponents or playback; and 4. Quick answers to vocalizations of mates, opponents, and playback were with rreet, also uttered during attack behavior. Functionally, birds uttering the unassertive vocalizations (weep, weeuh, and thrr) may have been taking only minimal initiative to interact, and simply advertising their presence and potential responsiveness. With increasing numbers of churr, subjects maintained social contact with mates or opponents or probed for responses from quieter birds. Wit and weihp may strongly provoke opponents to respond. Further escalation involved met, weed, and wi. In contrast, ch-ee was a defensive threat. This species sings with more vocalizations than do other tyrannids we have studied. Its vocalizations correlate with relatively fine distinctions among behavioral categories. Yet the vocalizations, like those of the other species, provide information about different extents of initiative that a singer will show in interacting. Such information could be fundamentally important in shaping and stabilizing social relationships, not just of tyrannids but also of many other kinds of animals that use singing to interact with one another while at a distance.     

The use of vocal signals in the social play of barbary macaques

Field studies in various species ofMacaca (Cercopithecidae) provided evidence for specific visual displays that typically accompany playful interactions. The aim of our study was to examine whether and when playing individuals would use auditory displays, i.e. vocalizations that often occur during social play as well. The study was conducted on a population of semi-free Barbary macaques (Macaca sylvanus) with a special focus on the composition and dynamics of playful wrestling (synonymous term: ‘rough-and-tumble play’). Analyses of dyadic encounters between subadult males allowed us to distinguish five types of playful behaviours and three types of vocalizations. The latter were clearly linked to encounters where effects of visual signals were impaired, e.g. during close body contact. During wrestling, vocalizations tended to increase in the beginning of an encounter, whereas the last seconds of wrestling often showed a decline in vocalization rate. Our results allowed us to conclude that these vocalizations may supplement or in many cases even substitute interactional effects of visual signals, e.g. the ‘play face.’     

Male-female interactions and socio-sexual isolation of Mus spicilegus toward two other species of east-European mice, M. macedonicus and M. m. musculus.

Social and sexual interactions were analysed as potential behavioural processes assessing reproductive isolation between the mound-building mouse, Mus spicilegus, and two other wild species, M. macedonicus and M. musculus. Dyadic encounters among strange M. spicilegus individuals and between M. spicilegus and the two other species members were conducted with females in an oestrus state. In intraspecific M. spicilegus encounters, there was a high incidence of close contact behaviours initiated by the females. In interspecific encounters M. musculus males and females and M. macedonicus females showed social interest toward their M. spicilegus protagonists, whereas the later behaved in an unfriendly or aggressive manner. Thus socio-sexual interactions shown by the different species seem to be sufficient to prevent any attempt to mate interspecifically. Arguments in favour of recognition against reinforcement hypothesis are discussed.     

Social Interaction is Necessary for Discrimination between and Memory for Odours of Close Relatives in Golden Hamsters

The role of social experience in recognition of individuals and their odours is not well understood. In a previous study, hamsters discriminated between the odours of their familiar litter mates, but they did not discriminate between the odours of two males or two females from a different litter that were unfamiliar to them. In this paper the role of social experience in discrimination between odours of male litter mates is examined using habituation techniques. Males, tested 1.5–2 mo after separation from their litter mates, discriminated between the flank gland odours of their foster brothers, but they did not discriminate between flank odours from their unfamiliar brothers that had been reared by another mother (Expt. 1). In Expt. 2, adult males did not discriminate between the flank gland odours of two males from a different litter after a week of exposure across a barrier to their sights, sounds, and odours, but subjects did discriminate between the odours of these same males after five brief encounters with them. A month after the encounters, however, subjects no longer discriminated between these odours. In contrast, adult males discriminated between the flank odours of their brothers 9 mo after separation from them (Expt. 3). These results suggest that hamsters must have direct interactions with closely related individuals to discriminate between their odours because the odours of close kin are so similar. Experience with nest mates results in long-lasting memories for their odours.     

Function of male song in the greater white-lined bat, Saccopteryx bilineata

The use of vocalizations by males to attract mates and defend territories is widespread in birds but uncommon in mammals. In the greater white-lined bat, males defend small territories in tree buttresses and produce complex audible vocalizations. During the day, females roost within these territories, and males with females in their territories have higher reproductive success than males without females. To determine call function, we recorded male vocalizations on the island of Trinidad and made behavioural observations of the focal male and nearby bats at the time the calls were given. Noisy broadband calls were directed mainly at other males whereas tonal calls were used primarily in interactions with females. Two other types of calls were given independently of any observable context and may be involved in territorial defence or conspecific notification. Poisson regression showed that males with song repertoires that contained more unique types of composite syllables had more females in their territories. In addition, several acoustic features of one common call type significantly correlated with the number of females on a territory. Male vocalizations may, therefore, transfer information to colony members about male quality or fighting ability.     

Why do curly tail lizards (genus Leiocephalus) curl their tails? An assessment of displays toward conspecifics and predators

Animal display behaviors are used to convey specific messages to other animals, including potential mates, rivals, and predators. However, because these different types of interactions can be mediated by a single behavioral display, or conversely, multiple signals can be used to convey one specific message, interpretation of any particular behavioral display can be difficult. Leiocephalus lizards (i.e., curly tails) provide an excellent opportunity to study the use of display behaviors across multiple contexts. Previous research has demonstrated that the use of tail curling in these lizards is associated with predation risk, but less is known regarding the use of this behavior in social interactions with conspecifics. The goal of this study was to determine the extent to which tail curling display behavior is used to mediate both social and predatory interactions in two species, Leiocephalus barahonensis and L. carinatus. We found that in lizards of both species, tail curling was used in interactions with both conspecifics and potential (human) predators. However, tail curl intensity did not differ between lizards involved in social encounters and solitary lizards, although L. barahonensis lizards performed more headbobs during social than non‐social observations. Further, L. carinatus lizards exhibited greater intensity of tail curling upon fleeing from a human predator than during observations in which individuals interacted with conspecifics, and lizards that exhibited tighter tail curls fled from predators for a longer distance. Finally, tail curl intensity was not correlated with headbob displays in either species, suggesting that these two components of display communicate different information. Our results suggest that tail curling displays, while consistently a component of interactions with potential predators, are not a necessary component of social interactions. These data contribute to a more complete understanding of how and why visual signals evolve for use in communication across multiple contexts.     

VOCAL REPERTOIRE OF WILD BREEDING ORANGE-WINGED PARROTS AMAZONA AMAZONICA IN AMAZONIA

ABSTRACT

The vocal repertoire of Amazona amazonica during its breeding season has been recorded from wild individuals in Santa Bárbara do Pará, Pará State, Brazil. At individual nests, we continuously recorded vocalizations and behaviour for four hours in the early morning and three hours in the late afternoon, three times a week throughout the breeding season. We identified nine vocalizations that we classified in three behavioural categories: (1) Flight call—emitted when parrots arrive in the nest area; (2) Perched contact calls—two different vocalizations, one of them related to feeding, were emitted when the pair was perched in the nest area and interacted socially between themselves or with other individuals; (3) Aggressive calls—emitted when birds were in a dangerous situation, i.e. alarm (three types of calls), agonistic contact and distress calls (two types of call). The Orange-winged Parrot is a highly social species and the complexity of its social interactions is reflected in the diversity of its vocal repertoire.     

Vocal Repertoire of Cebus capucinus: Acoustic Structure, Context, and Usage

Researchers studying nonhuman primate vocal repertoires suggest that convergent environmental, social, and motivational factors account for intra- and interspecific vocal variation. We provide a detailed overview of the vocal repertoire of white-faced capuchins, including acoustic analyses and contextual information of vocal production and vocal usage by different age-sex classes in social interactions. The repertoire is a mixture of graded and discrete vocalizations. In addition, there is general support for structural variation in vocalizations with changes in arousal level. We also identified several combined vocalizations, which might represent variable underlying motivations. Lastly, by including data on the social contexts and production of vocalizations by different age-sex classes, we provide preliminary information about the function of vocalizations in social interactions for individuals of different rank, age, and sex. Future studies are necessary to explore the function of combined vocalizations and how the social function of vocalizations relate to their acoustic structure, because social use of vocalizations may play an important role in shaping vocal evolution.     

Carotenoid‐based bill coloration functions as a social,not sexual,signal in songbirds (Aves: Passeriformes)

Many animals use coloration to communicate with other individuals. Although the signalling role of avian plumage colour is relatively well studied, there has been much less research on coloration in avian bare parts. However, bare parts could be highly informative signals as they can show rapid changes in coloration. We measured bill colour (a ubiquitous bare part) in over 1600 passerine species and tested whether interspecific variation in carotenoid‐based coloration is consistent with signalling to potential mates or signalling to potential rivals in a competitive context. Our results suggest that carotenoid bill coloration primarily evolved as a signal of dominance, as this type of coloration is more common in species that live in social groups in the nonbreeding season, and species that nest in colonies; two socio‐ecological conditions that promote frequent agonistic interactions with numerous and/or unfamiliar individuals. Additionally, our study suggests that carotenoid bill coloration is independent of the intensity of past sexual selection, as it is not related to either sexual dichromatism or sexual size dimorphism. These results pose a significant challenge to the conventional view that carotenoid‐based avian coloration has evolved as a developmentally costly, condition‐dependent sexual signal. We also suggest that bare part ornamentation may often signal different information than plumage ornaments.     

Vocal Repertoire of Golden-backed Uakaris (<Emphasis Type="Italic">Cacajao melanocephalus</Emphasis>): Call Structure and Context

The study of vocal behavior can reveal important aspects of how and why a species communicates in relation to ecological and social challenges. We here focus on vocal communication in golden-backed uakaris (Cacajao melanocephalus), diurnal, pitheciine monkeys that exhibit fission-fusion social organization and typically inhabit dense forests that limit the potential for visual communication. Moreover, the species spends little time engaged in tactile or olfactory communication, e.g., social grooming and scent marking, respectively. Hence, vocalizations may be very important for the coordination of social organization in these monkeys. We 1) categorized golden-backed uakari vocalizations, 2) ascertained their behavioral context, and 3) investigated whether golden-backed uakari calls can encode information about the signaler. We observed the monkeys during 2 wet seasons in the flooded igapó forest of Jaú National Park, Brazil. We showed that golden-backed uakaris have 9 call types in their vocal repertoire, all distinguishable by ear and from analysis of spectrograms. Some calls, e.g., play-specific calls, were used only in particular behavioral contexts, and by individuals of specific age, whereas others were emitted under a range of situations. The structure of the loud tchó call varied among individuals, and according to behavioral context, i.e., whether individuals were foraging/feeding, traveling, or performing agonistic interactions. This knowledge of the species’ vocal repertoire is valuable for surveying the monkeys acoustically in habitats where visual surveys are difficult.     

Early singers attend to conspecific but not heterospecific behavioural cues at dawn

During the dawn chorus songbirds initiate singing activities just prior to sunrise. Environmental factors affect the timing of the dawn chorus, but relatively little is known about how behavioural cues influence chorus timing. We assessed whether early playback of conspecific and heterospecific song influenced chorus start times in two early‐singing temperate species, hermit thrush Catharus guttatus and veery C. fuscescens. We used arrays of GPS time‐synchronized recorders to record the dawn chorus at 30 locations. In each location, thirty minutes prior to natural chorus initiation, we broadcast: 1) an early singing species (hermit thrush or veery), 2) a late singing species (black‐throated green warbler Setophaga virens or Nashville warbler Oreothlypis ruficapilla), 3) a noise control, and 4) also recorded without playback (silent control). Playback treatments were separated by two‐three days at each location. Both hermit thrush and veery sang significantly earlier in response to conspecific playback compared to noise or silent controls. Both species also sang earlier in response to conspecific playback compared to the day before or the day after playback. Neither species sang earlier in response to heterospecific playback (regardless of whether the broadcast species was a naturally early or late song initiator) compared to noise or silent controls. Our results support the theory that the dawn chorus is a communication network where individuals attend primarily to conspecific cues; heterospecific song appears to have minimal impacts on the chorus start times of the two early‐singing species we investigated.     

Anthropogenic noise affects female,not male house wren response to change in signaling network

Vocal signals mediate social relationships, and among networks of territorial animals, information is often shared via broadcast vocalizations. Anthropogenic noise may disrupt communication among individuals within networks, as animals change the way they vocalize in noise. Furthermore, constraints on signal transmission, including frequency masking and distance, may affect information exchange following a disruption in social networks. We tested the hypothesis that signaling interactions within networks of breeding male and female house wrens (Troglodytes aedon) depend on distance, ambient noise, and receiver nesting stage. We used playback experiments to simulate territorial intrusions with and without noise playbacks on the territories of established males and simultaneously recorded the vocal responses of neighbors. To examine whether intrusions impacted interactions between males, we used randomization tests to determine whether treatment, distance, noise, or nesting stage affected vocal coordination between challenged and neighboring males. We also quantified singing patterns to explore whether intrusions on territories of challenged males affected singing by males and females on neighboring territories. Males sang at the lowest rates and were less likely to overlap songs with the challenged male when their partner was laying, compared to males during early and late nesting stages. Noise and distance did not affect vocal coordination or male singing rates. Fewer females sang during the intruder-only treatment compared to the control and intrusions with noise. Added noise in the territories of challenged males may have masked signals, and as a result, females only changed their behavior during the intruder-only treatment. Our results suggest that the fertility of breeding partners may be more important to males than short-term changes on rival male territories. Elevated noise did little to alter male responses to threats within networks. Females appeared to eavesdrop on interactions involving neighboring males, but noise may have prevented detection of their interactions.     

Quality, Quantity, Distribution and Audience Effects on Food Calling in Cotton—Top Tamarins

Despite extensive documentation in many taxa of vocalizations specific to feeding contexts, little is known of the variables leading to production of food-associated calls. We thus experimentally investigated food-associated calls in cotton-top tamarins ( Saguinus oedipus ). In one experiment, we examined the roles of food quantity, quality and distribution and of social condition of individuals on food-associated calling. Paired adults without offspring gave more vocalizations than immature individuals and adults with offspring. We observed no effects of food quantity or distribution on calling rate. Tamarins called more often to peaches, a food of intermediate preference that was also consumed the fastest. Tamarins gave more food-associated calls when in closer proximity to other group members. Low rates of moderate aggression were observed in single, but not multiple, feeder conditions. We saw no consistent evidence of dominance among adults, and all aggression in family groups was directed toward immature animals. In another experiment, we presented a tamarin with food in a separate cage, either in view of or visually isolated from its mate. Tamarins presented with food called at an equal rate whether or not their mates were visible, suggesting no effect of audience on calling. Individuals not presented with food called in response to the food calls of their mates equally often, irrespective of whether or not the mate or the food was visible. Since food calling occurs at extremely low rates in the absence of food, the food calling by tamarins that cannot see the food suggests that the calls of their mates provide representational information about food.     

Do great tits assess rivals by combining direct experience with information gathered by eavesdropping?

Animals frequently use signals that travel further than the spacing between individuals. For every intended recipient of a given signal there are likely to be many other individuals that receive information. Eavesdropping on signalling interactions between other individuals provides a relatively cost-free method of assessing future opponents or mates. Male great tits (Parus major) extract relative information from such interactions between individuals unknown to them. Here, we show that male great tits can take information gathering a stage further and obtain more information about a previously unencountered intruder, by the hitherto unknown capability of combining information gathered by eavesdropping with that derived from their own direct interaction with an individual. Prior experience with an intruder (A) was achieved by subjecting a focal male to different levels of intrusion simulated using interactive playback. This intruder (A) then took part in a simulated interaction with an unknown male (B) outside the territorial boundary of the focal males. In response to subsequent intrusion by the second male (B), focal males showed low song output in response to males that had lost to a male that the subject was able to beat. Males of known high quality, or those about which information was ambiguous, elicited a high level of song output by focal males. We discuss the implications of this finding for the evolution of communication and social behaviour.     

Variation in singing style use in the reed bunting Emberiza schoeniclus: influencing factors and possible functions

The two main functions of bird song are territory defence and mate attraction. Considerable progress has been made in understanding how species adjust the use of songs to serve these and other (presumed) functions of bird song, but the striking variety of singing behavior observable in wild birds remains enigmatic. Some species make do with simple songs and small repertoires, while others show large, complex repertoires and still others have evolved several distinct singing styles. In most species with distinct singing styles, however, the functions of singing styles are poorly understood. Two distinct singing styles (type I and II, respectively) have long been known in the reed bunting Emberiza schoeniclus, while a new third one has recently been reported to exist. We first quantitatively investigated the evidence for the existence of three singing styles. Then, we tested predictions of the mate attraction hypothesis, the mate guarding hypothesis and the territory defence hypothesis by examining the relations between singing style use with social and temporal factors. Cluster and discriminant analyses supported the existence of three (instead of two) singing styles, which could be differentiated based on four variables referring to song structure and complexity. Use of singing styles was related to male mating status (consistent with the mate attraction hypothesis), but not to female breeding stage (no support for the mate guarding hypothesis). Finally, use of singing styles differed in relation to time of day, with the dawn chorus of paired reed buntings consisting almost exclusively of songs of the recently discovered type III singing style and daytime singing primarily consisting of songs of long‐known type I (in unpaired males) or II singing styles (in paired males). Our findings suggest that one singing style (type I) primarily serves to attract a social mate, although an additional territorial function of this singing style cannot be dismissed. The function(s) of the other two singing styles, both only sung by paired males, are not related to attraction of a social mate or to the own female's fertility, but appear to be important in the context of territory defence and extra‐pair matings.     

Neural correlates of learned song in the avian forebrain: simultaneous representation of self and others

Songbirds are extraordinary vocalists and sensitive listeners, singing to communicate identity, engage other birds in acoustical combat, and attract mates. These processes involve auditory plasticity in that birds rapidly learn to discriminate novel from familiar songs. Songbirds also are one of the few non-human animals that use auditory feedback to learn their vocalizations, thus auditory -- vocal interactions are likely to be important to vocal learning. Recent advances strengthen the connection between song recognition and processing of birdsong in the auditory telencephalon. New insights also have emerged into the mechanisms underlying the 'gating' of auditory responses and the emergence of highly selective responses, two processes that could facilitate auditory feedback important to song learning.     

Opening the Social Gateway: Early Vocal and Social Sensitivities in Brown-Headed Cowbirds (Molothrus ater)

The organization of cowbird ( Molothrus ater ) social groups affords individuals living in the groups different opportunities for learning and also structures trajectories of social development. Here, we studied the influence of adults on social organization of very young cowbirds. In three experiments, we housed juvenile birds in large, seminatural environments that either contained or did not contain adult conspecifics. We then observed the social associations and vocalizations of juveniles in each environment. The presence of adults in the social environment influenced the assortment and singing patterns of juveniles, although throughout the three experiments adults rarely interacted physically with juveniles. Juveniles housed with adults interacted with other juveniles more often and sang significantly less often than juveniles housed without adults. Effects of adult presence or absence on social organization and singing patterns emerged extremely rapidly and could be reversed quickly. Taken as a whole, the experiments revealed that very young cowbirds, in the first days of independence from their hosts, were sensitive to, and reacted rapidly to, the composition of their social environment. Specifically, presence of other age classes of individuals within the group increased juvenile associations and delayed production of vocalizations by juvenile males. Self-organization within the social group produced different social environments, which could in turn create different gateways for social learning and vocal development.     

Conspecific discrimination in an object-choice task in African grey parrots (Psittacus erithacus)

Living in social groups presents the opportunity to use information provided by other individuals. Several animal species emit specific vocalizations when they find food. Here, we investigate whether African grey parrots (Psittacus erithacus) use vocal and non-vocal information provided by a conspecific in order to find a hidden food source. One subject was attracted by the presence or the vocalizations of a subordinate conspecific, but not of a dominant, which brings us to hypothesize that parrots could be capable of individual vocal discrimination.     

Songs,Choruses and Countersinging of Kloss' Gibbons (Hylobates klossii) in Siberut Island,Indonesia

This study evaluates the social spacing mechanism of song as it occurs in Kloss' gibbons. The study population included individuals in 13 family groups whose composition and territories were known (Tenaza 1975) plus a number of others. Sonagrams illustrate individual and sexual differences in singing. Sex differences in chorusing, countersinging and other behavior related to song are described. Variations in singing or chorusing or both are related to season, time of day, sex, age, spatial factors and social factors. The adaptive functions of singing, countersinging and chorusing are discussed. It is concluded that: (1) Song is mainly for interterritorial communication between members of the same sex, (2) ♂ -song probably also functions in mate attraction and (3) chorusing is primarily an adaptation reducing predation risk to singing gibbons.