Full Song Research Articles

QUIET SONG IN SONG BIRDS: AN OVERLOOKED PHENOMENON

ABSTRACT The theory of communication networks offers functional arguments for the evolution of unobtrusive signals in birds. The vulnerability of interacting conspecifics to predation and to eavesdropping by neighbours during both territorial disputes and courtship would select for short range signals such as the quiet songs of birds. In addition to suggesting contexts in which quiet songs should be used, we use our knowledge of the physics of sound transmission to make predictions about the physical structure of such songs relative to the well studied full songs. We present support for these predictions in six species where quiet singing has been observed.

Adult bengalese finches (Lonchura striata var.domestica) require real-time auditory feedback to produce normal song syntax

Songbirds develop their songs by imitating songs of adults. For song learning to proceed normally, the bird's hearing must remain intact throughout the song development process. In many species, song learning takes place during one period early in life, and no more new song elements are learned thereafter. In these so-called close-ended learners, it has long been assumed that once song development is complete, audition is no longer necessary to maintain the motor patterns of full song. However, many of these close-ended learners maintain plasticity in overall song organization; the number and the sequence of song elements included in a song of an individual vary from one utterance to another, although no new song elements are added or lost in adulthood. It is conceivable that these species rely on continued auditory feedback to produce normal song syntax. The Bengalese finch is a close-ended learner that produces considerably variable songs as an adult. In the present study, we found that Bengalese finches require real-time auditory feedback for motor control even after song learning is complete; deafening adult finches resulted in development of abnormal song syntax in as little as 5 days. We also found that there was considerable individual variation in the degree of song deterioration after deafening. The neural mechanisms underlying adult song production in different species of songbirds may be more diverse than has been traditionally considered.

Bengalese FinchesLonchura Striata DomesticaDepend upon Auditory Feedback for the Maintenance of Adult Song

Male birds of age-limited song-learning species develop their full song repertoires in the first year of life. For this type of song learner, once song is stabilized in adulthood, it is highly stereotyped and stable over time. Traditionally, it has been believed that age-limited song learners do not depend on auditory feedback for the maintenance of adult song. A recent report, however, showed that adult song in zebra finches, age-limited learners, does change after long-term deafness. We report here that another species of age-limited learner, Bengalese finches, depends critically on auditory feedback for adult song maintenance. We surgically deafened adult males and recorded song for 12 weeks after surgery. Results show that song degraded significantly within 1 week of surgery and continued to degrade over the next 11 weeks. This represents a more rapid degradation of song than has been seen previously in age-limited species. Song deficits after deafening included a marked decrease in syllable sequence stereotypy, skewed syllable distribution within song bouts, degradation of syllable phonology, and dropped, combined, and new or unrecognizable syllables. Decreased sequence stereotypy and combined syllables appeared within 1 week of deafening and did not worsen over time. Skewed syllable distributions and syllable phonology changes appeared after 1 week and did worsen. Occurrences of dropped and new syllables appeared within 1 week and increased over time. Comparison with other species indicates that much variability exists among species in the extent to which auditory feedback is necessary for song maintenance.

Intraventricular infusion of arginine vasotocin induces singing in a female songbird.

Arginine vasotocin (AVT) has been implicated in the activation of courtship and aggressive behaviors in many vertebrate taxa. Here, we tested its effect on singing and other vocal behavior in a songbird. Female white-crowned sparrows (Z. l. gambelii) were implanted with chronic cannulae aimed at the third ventricle. Infusions of AVT dramatically increased the number of songs and other vocalizations during a 40 min period following infusion. Half of the subjects sang full song following AVT treatment. No bird sang after treatment with saline; any type of vocalization after saline treatment was rare. Female white-crowned sparrows are known to sing in both spring and winter in the wild; this behavior is thought to be aggressive, functioning in dominance interactions and territoriality. Central infusion of AVT induced singing and other vocalizations in estrogen-primed, photostimulated subjects as well as in non-reproductive subjects housed on short photoperiods. Thus, the effects of AVT on vocal behavior may not require breeding levels of gonadal steroids and are probably not seasonal. We hypothesize that both in the breeding and non-breeding seasons, AVT increases motivation to sing.

Testosterone Induces Sexual Release Quality in the Song of Female Canaries

AbstactWe tested the sexual responsiveness of female canaries, Serinus canaria, to two sets of different types of female conspecific songs versus an adult male conspecific song. Female songs were either spontaneously emitted (‘S‐songs’) or were testosterone‐induced (‘T‐songs’). Copulation‐solicitation displays (CSD) were used as an index of female sexual response. Playbacks were performed several days before and during egg laying, a period of natural sexual responsiveness of the females to song. We demonstrated that the weaker sexual displays of female canaries were recorded to S‐songs, thus suggesting that these types of female songs do not contain fully functional sexual releasers. Three T‐songs elicited high levels of sexual displays, thus demonstrating that testosterone treatment may induce sexual release quality in the female songs. Study of the phonology of these three T‐songs strongly suggested that special song phrases may be good candidates as powerful sexual releasers. To test the sexual value of these female song phrases, we carried out a third experiment, using hybrid songs where each of these special T‐song phrase types was included in a well‐known heterospecific context. Two phrases elicited high levels of sexual responses in females. Essential features of the male full song, such as broadband rapid frequency modulations and high repetition rate, are retrieved in both female song phrases. Taken together, these data demonstrate that testosterone treatment not only induces a male‐like structure in the songs of females, but also induces functionally ‘male‐like’ songs. This result allows features of the vocal control network of testosterone‐treated females to be compared with those of adult males singing full songs, to distinguish neural correlates of testosterone‐dependent full songs. However, because testosterone does not induce functionally male‐like songs in all the females, neuroanatomical structure‐function correlations need detailed behavioural analysis.

WHERE TO SING AND WHERE TO CALL. VOCALIZATIONS OF CHAFFINCHESFRINGILLA COELEBSINSIDE AND OUTSIDE THEIR TERRITORIES

ABSTRACT The spatial distributions of chaffinch full song and some of the calls are described with regard to the territories. Full songs of five colour ringed and transmitter marked males occurred mainly inside and in a few cases outside the territories. These events are interpreted as attempts by the birds to enlarge their territories. Rain calls and courtship tchirp calls were restricted to the singing territories. The social chink call was frequently uttered outside the territories as a means of intra-pair communication.

Habitat-induced degradation of sound signals: Quantifying the effects of communication sounds and bird location on blur ratio, excess attenuation, and signal-to-noise ratio in blackbird song

The habitat-induced degradation of the full song of the blackbird (Turdus merula) was quantified by measuring excess attenuation, reduction of the signal-to-noise ratio, and blur ratio, the latter measure representing the degree of blurring of amplitude and frequency patterns over time. All three measures were calculated from changes of the amplitude functions (i.e., envelopes) of the degraded songs using a new technique which allowed a compensation for the contribution of the background noise to the amplitude values. Representative songs were broadcast in a deciduous forest without leaves and rerecorded. Speakers and microphones were placed at typical blackbird emitter and receiver positions. Analyses showed that the three degradation measures were mutually correlated, and that they varied with log distance. Their variation suggests that the broadcast song could be detected across more than four, and discriminated across more than two territories. The song’s high-pitched twitter sounds were degraded more rapidly than its low-pitched motif sounds. Motif sounds with a constant frequency projected best. The effect of microphone height was pronounced, especially on motif sounds, whereas the effect of speaker height was negligible. Degradation was inversely proportional to microphone height. Changing the reception site from a low to a high position reduced the degradation by the same amount as by approaching the sound source across one-half or one-whole territory. This suggests that the main reason for a male to sing from a high perch is to improve the singer’s ability to hear responses to its songs, rather than to maximize the transmission distance. The difference in degradation between low and high microphone heights may explain why females, which tend to perch on low brush, disregard certain degradable components of the song.

Memory Does Not Constrain Individual Recognition in a Bird With Song Repertoires

Summary We tested the hypothesis that memory or perceptual limitations imposed by song repertoires contrain the ability of song birds to recognize their neighbours by song. Using operant conditioning procedures, we trained male song sparrows (Melospiza melodia) (median repertoire size = 8) to discriminate between two artificial song sparrow repertoires of 32 songs each (64 songs total). Both song sparrows learned to discriminate concurrently between all 32 song pairs. The birds learned later songs as quickly as they learned earlier songs. These results suggest that song sparrows are capable of memorizing the full song repertoire of their neighbours under natural conditions. In a second experiment we found that song sparrows readily generalize from one exemplar of a song type to other variations of that song type. We conclude that the evolution of song repertoires of song sparrows have neither constrained nor been constrained by individual recognition of neighbours by song.

Species recognition of song by female red-winged blackbirds

The ability of female red-winged blackbirds, Agelaius phoeniceus, to discriminate between normal songs of local, conspecific males and altered or foreign songs was tested. Females were tested using the solicitation display assay, in which captive females are first treated with oestradiol and then exposed to playback. The number of copulation solicitation displays was the sole response measure. Females responded more strongly to full songs than to songs with all introductory notes removed in tests using nine pairs of stimuli. Females did not discriminate between normal songs and the same songs divided into three parts and reassembled in shuffled orders. Subjects drawn from a Pennsylvania population displayed more in response to local songs than songs recorded in California. Pennsylvania females also responded more strongly to trill portions of Pennsylvania songs than to trill portions of California songs. Overall, the results are compatible with the hypothesis that female red-winged blackbirds are more discriminating than males in species recognition, attending to more acoustic cues than do males.

ANNUAL CHANGES OF LEARNED BEHAVIOUR—VARIATION OF SONG PATTERN IN FREE-LIVING CHAFFINCHES,FRINGILLA COELEBS, DURING THE BREEDING SEASON

ABSTRACT Seasonal changes of parameters of full song were studied in a free-living population of chaffinches Fringilla coelebs during one entire reproductive period. Approximately 7000 strophes sung by 14 male chaffinches were recorded and analysed by sonography and a particular oscillographic method. While the general pattern of song strophes, i.e. characteristics of elements, number and arrangement of phrases, and final flourish, remained constant throughout the reproductive period, full song varied with respect to the repetition rate of strophes, number of strophe types used, intensity of singing, duration of strophes, and percentage of incomplete strophes sung. These changes are discussed as results of learning processes, social interactions in the population, and endogenous mechanisms activating memorized information.

Song learning in montane white-crowned sparrows: from whom and when

White-crowned sparrow, Zonotrichia leucophrys, adults and nestlings were colour-banded and songs of mature progeny recorded to determine whether songs were learned from fathers, age peers or adults other than fathers. Four out of 17 sons and daughters sang the same song types as their fathers, indicating that transmission of song from fathers to their young (vertical transmission) is not the norm. Since juveniles do not sing full (‘crystallized’) songs until they are older, transmission from juvenile to juvenile (horizontal) is unlikely on the breeding grounds but may occur if siblings migrate together and hear each other's song on the wintering grounds. The usual mode of transmission is via other adults (oblique). Birds learn one or two songs prior to or during migration, and upon settling on the breeding area the following year may utter only one theme, that which matches the neighbours' songs during matched countersinging bouts. A bird's song dialect is thus not necessarily an indicator of its birthplace. One wild and one laboratory-reared bird sang songs of a Lincoln sparrow, Melospiza lincolnii, and a strawberry finch, Amandava amandava, respectively. These data and data from field playback studies lend support to the notion that interspecific terrioriality may lead to acquisition of alien song for use in matched countersinging during territorial encounters with allospecific neighbours.

The Meaning of the Full Song of the Blackbird Turdus merula to Untreated and Estradiol Treated Females

The Meaning of the Full Song of the Blackbird Turdus merula to Untreated and Estradiol Treated Females

Developmental and seasonal changes in canary song and their relation to changes in the anatomy of song-control nuclei

Young male canaries become sexually mature in late winter, 8-12 months after hatching. During the months between hatching and sexual maturity they develop adult song. The successive stages in the development of adult song are subsong, plastic song, and stable or full song. Once stable song is achieved it lasts for the duration of the breeding season. After the end of the breeding season there is a recurrence of song instability during summer and early fall. This plastic song is followed, once more, by stable song. New song syllables are added to the song of adult male canaries and some of the earlier syllables disappear. The song repertoire sung at 2 years of age is substantially larger, and different, from that sung during the first breeding season, when the birds were 1 year old. A comparable change occurs between the second and third breeding seasons. Most of the syllables acquired by adult males are formed during the summer-fall period of song instability. Developmental and seasonal changes in song are accompanied by anatomical changes in two forebrain nuclei known to be involved in song control, the hyperstriatum ventralis, pars caudalis (HVc), and the robust nucleus of the archistriatum (RA). HVc and RA grow during the subsong and plastic song periods of song development. These nuclei reach adult size by the time stable adult song is first produced, and retain this size during the breeding season. However, the size of HVc and RA diminishes by late summer, when it becomes comparable to that of a 3- to 4-month-old bird. This reduction in size is temporary and has been corrected by the following breeding season. It is suggested that these seasonal changes in volume reflect circuit changes which are under hormonal control, and that these changes are related to processes of learning and, possibly, forgetting. Despite earlier reports of left hemispheric dominance in canary song production, we failed to find any evidence of right-left systematic differences in the size of HVc and RA during development or in adulthood. Various hypotheses relating song learning to changes in the underlying anatomy are offered.

Correspondence between Messages in the Full Song of the Blackbird Turdus merula and Meanings to Territorial Males, as Inferred from Responses to Computerized Modifications of Natural Song

Abstract and SummaryThe problem of correspondence between messages in the blackbird song and meanings to territorial males was examined in playback experiments in which the threat releasing effects of modified and unmodified songs were compared. The modification of the message content of the song was carried out by computer. The recording of the test song was digitalized, then processed, and finally converted back to analog form. Different song parameters were changed in a controlled way in proportion to their natural limits of variation. The following results were achieved:I. Removal of the motif parts showed that the integrity of the parameters “duration of phrases”, “duration of pauses between phrases” and “duration of motif parts” is essential to species recognition.II. Removal of the twitter parts showed that the integrity of the parameters “duration of phrases”, “duration of pauses between phrases” and “duration of twitter parts” is not essential to song recognition. Removal of the twitter parts only changes messages about degree of arousal and thus the meaning.III. Additional modifications to the time scale or the frequency level of test songs without twitter parts showed that the integrity of each of the following two groups of parameters is essential to species recognition in males:a) “Duration of motif part sound figures”, “duration of pauses between motif part sound figures”, “duration of motif parts” and “cadence of song‐delivery”, andb) “highest” and “lowest fundamentals of the motif part sound figures” and “highest” and “lowest fundamentals of motif parts”.IV. Finally, modification of the duration of the pauses between motif part sound figures showed that the integrity of the parameters “cadence of song‐delivery”, “duration of motif parts” and “duration of pauses between motif part sound figures” is not essential to species recognition.The natural limits of variation of the parameters have a potential for conveying a message about species. Parameters with narrow or wide limits of variation may be essential to species recognition. The reaction was significantly reduced when parameters were changed out to and especially beyond these limits whatever the range of variation, i.e. in this respect there is a correspondence between message and meaning.If the time scale or the frequency level was modified, changing parameters to give messages about increased or decreased arousal and no parameters essential for song recognition were changed to or beyond their limits of variation, a slightly stronger respectively weaker reaction was indicated. Thus there also seems to be correspondence betweeen message and meaning in this respect. There seems to be functional evidence that a song parameter may code for species identity and convey behavioural messages.ZusammenfassungMögliche Übereinstimmungen zwischen Nachrichteninhalt („message”) im Amselgesang und seiner Bedeutung („meaning”) für territoriale Amselmännchen wurden in Klangattrappen‐Versuchen geprüft. Verglichen wurde die reaktionsauslösende Wirkung von modifiziertem und nichtmodifiziertem Gesang. Der Nachrichteninhalt wurde folgendermaßen modifiziert: die Tonbandaufnahme vom Versuchsgesang wurde anfangs im Computer digitalisiert; dann wurden verschiedene Gesangsmerkmale in bestimmter Weise im Rahmen der natürlichen Variationsgrenzen geändert; dann wurde der „Gesang” zu analoger Form zurückgeführt.Klangattrappen, denen der Motivteil des Gesanges fehlt, werden anscheinend nicht mehr als Amselgesang erkannt. Die gesamte Einheit aus „Dauer der Strophen”, „Dauer der Pausen zwischen den Strophen” und „Dauer des Motivteils” ist für die Arterkennung entscheidend.Klangattrappen, denen der Trillerteil fehlt, werden als Amselgesang von niedriger Erregung erkannt.Versuche mit Klangattrappen, die nur aus Motivteilen bestanden und dazu in Bezug auf den Verlauf oder die Tonhöhe geändert waren, zeigten, daß jede der folgenden zwei Gruppen von Lautmerkmalen als Einheit für die Arterkennung entscheidend ist:1. „Dauer der Motivelemente”, „Dauer der Pausen zwischen den Motivelementen”, „Dauer des Motivteils” und „Kadenz der Strophenerzeugung”.2. „Höchste” und „niedrigste Grundtonfrequenz der Motivelemente” und „höchste” und „niedrigste Grundtonfrequenz des Motivteils”.Weitere Versuche mit Veränderungen der Pausen zwischen den Motivelementen zeigten, daß die Einheit aus den Lautmerkmalen „Dauer der Pausen zwischen den Motivelementen”, „Dauer des Motivteils” und „Kadenz der Strophenerzeugung” für die Arterkennung unwesentlich ist.Sowohl Gesangsmerkmale mit geringer als auch solche mit großer Variationsbreite sind für die Arterkennung wesentlich. Unabhängig von der Größe der Variationsbreite nahmen die Reaktionen erst dann signifikant ab, wenn Gesangsmerkmale bis zu den artcharakteristischen Variationsgrenzen und darüber hinweg verändert wurden.Damit ist eine Übereinstimmung zwischen senderseitigem Nachrichteninhalt und empfängerseitiger Bedeutung für die Arterkennung territorialer Amselmännchen nachgewiesen. Es scheint auch eine solche Übereinstimmung für den Erregungsgrad zu bestehen. Die Resultate stützen die Theorie, daß ein Gesangsmerkmal gleichzeitig über die Art und den Erregungsgrad des Vogels informieren kann.

An Analysis of the Full Song of the Blackbird Turdus merula with Respect to Message Coding and Adaptations for Acoustic Communication

The full song of the Blackbird was analysed quantitatively by means of sonagraph, level recorder and computer. Species-specific limits of variation are given for a number of song parameters. Some of these parameters vary between individuals, others vary within individuals in two situations, viz. dawn song with heavy stimulation from rivals and evening song with weak stimulation from rivals. The parameters and the differences between the variations of the parameters all seem to be within the range of auditory perception of oscines. It is therefore hypothesized that parameters varying within species-specific limits have a potential for conveying a message about the species, and that parameters varying within these limits with the individual or the situation have an additional potential for conveying individual or behavioural messages, respectively. Blackbird song was also studied with respect to adaptations for acoustic communication. Selection has favoured the evolution of a functionally divalent signal, the motif parts being adapted for long-range communication and the twitter parts for short-range communication.

Sugar concentration and the structure of the sunbird's song

The full song of the yellow-bellied sunbird (Nectarinia venusta) comprises distinct phrases, which retain their typical three-part structure and temporal organization regardless of the concentration of the sucrose solution provided. However, the sugar concentration does affect the types of elements that make up the initial part of the phrase and the number of elements in the terminal part. Several types of elements may be produced either as separate calls or as components of the initial part of the phrase; as the concentration decreases, at least two of these element types occur progressively more often in the phrases, taking the place of others.

Seasonal and diurnal variation in vocal behaviour of the South Island robin

Abstract The proportion of time spent by South Island robins (Petroica australis australis) of different sex, age, and status giving full song, subsong, and downscales, on a monthly and diurnal basis, is described. Females never gave full song. Males did so throughout the year, but least while moulting. Since bachelors sang significantly more than paired males, song probably functioned largely to attract females. Breeding males sang most during the pre-laying stage. From January to April adult males sang significantly more than immature males, but from May to July the reverse was true. Robins sang mainly in the early morning. Robins generally spent less than 0.5% of time during any stage of the breeding cycle giving sub-song. Outside the breeding season, males spent significantly more time giving sub-song than females, and adult males sang more than immature males. Robins in all categories gave more sub-song during the moult than afterwards. The diurnal pattern of sub-song production was bimodal. About ha...

Ontogeny of Song Recognition in Birds

SYNOPSIS. This paper reviews song recognition in two congeneric species of sparrow the swamp sparrow ( Melospiza georgiana ) and song sparrow ( Melospiza melodia ). Data from psychophysical studies of hearing, tutoring experiments with young birds, and field playback studies with adult birds are considered together in order to gain insight into the mechanisms of species recognition through song development. In aggregate, the evidence suggests a multi-stage process of song development consisting of an early perceptual preference for learning conspecific song, a sensorimotor phase of song development during which vocal output matches an auditory memory as if through trial and error, and a final phase of full song which functions in territorial defense and mate attraction.

Developmental overproduction and selective attrition: new processes in the epigenesis of birdsong.

All phases of song development from infancy to adulthood were studied intensively in a group of laboratory-reared birds. Male swamp sparrows, Melospiza georgiana, trained with tape-recorded songs in infancy, developed song some 8 months later, averaging 2.2 song types per bird. Analysis of the intermediate stage of plastic song revealed that the birds generated 4 to 5 times more song material than was needed for the species-specific song repertoire. The excess was discarded at the time of full song crystallization. Indications that the attrition process is selective include tendencies to retain imitated rather than nonimitated elements, and the rejection of heterospecific elements. Attrition may also be influenced by vocal stimulation at the time of song crystallization, providing an opportunity for behavioral adjustment even though new themes can no longer be learned. Attrition has been described in the transition in human infants from babbling to speech.

Einfluß der Konzentration der Zuckerlösung auf den Gesang und das Balzverhalten des Gelbbauchnektarvogels (Nectarinia venusta)*

Different concentrations of a sucrose solution vary the courtship song and behaviour of the male yellow-bellied sunbird Nectarinia venusta- the duration of subsong, total singing duration, and the absolute number of full song phrases. With high concentrations the sunbird sings more full song phrases but less subsong during the courtship season than otherwise. The various effects are described.