Discrimination of auditory distance cues by black-capped chickadees (Poecile atricapillus) and zebra finches (Taeniopygia guttata).

The authors examined auditory distance perception using a go/no-go operant discrimination task in the laboratory. They taught male black-capped chickadees (Poecile atricapillus) and male zebra finches (Taeniopygia guttata) to discriminate degraded (far) from undegraded (near) versions of male chickadee songs and female zebra finch calls, showing for the 1st time that males can discriminate distance cues in heterospecific vocalizations and in female calls. Chickadees learned faster than zebra finches, and both species learned to discriminate chickadee songs faster than zebra finch calls. Chickadees more than zebra finches attended to amplitude in tests pitting it against other distance cues, demonstrating that amplitude is a potentially useful cue for estimating distance from vocalizations. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effect of acoustic cue modifications on evoked vocal response to calls in zebra finches (Taeniopygia guttata).

Besides their song, which is usually a functionally well-defined communication signal with an elaborate acoustic structure, songbirds also produce a variety of shorter vocalizations named calls. While a considerable amount of work has focused on information coding in songs, little is known about how calls' acoustic structure supports communication processes. Because male and female zebra finches use calls during most of their interactions and answer to conspecific calls without visual contact, we aimed at identifying which calls' acoustic cues are necessary to elicit a vocal response. Using synthetic zebra finch calls, we examined evoked vocal response of male and female zebra finches to modified versions of the distance calls. Our results show that the vocal response of zebra finches to female calls requires the full harmonic structure of the call, whereas the frequency downsweep of male calls is necessary to evoke a vocal response. It is likely that both female and male calls require matching a similar frequency bandwidth to trigger a response in conspecific individuals. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Auditory scene analysis in Estrildid finches (Taeniopygia guttata and striata domestica): A species advantage for detection of conspecific song.

Operant-conditioning techniques were used to investigate the ability of zebra finches (Taeniopygia guttata) and Bengalese finches (Lonchura striata domestica) to detect a zebra finch or a Bengalese finch target song intermixed with other birdsongs. Sixteen birds were trained to respond to the presence of a particular target song, either of their own species (n?=?8) or of another species (n?=?8). The birds were able to learn a discrimination between song mixtures that contained a target song and song mixtures that did not, and they were able to maintain their response to the target song when it was mixed with novel songs. Zebra finches, but not Bengalese finches, learned the discrimination with a conspecific target more quickly and were worse at detecting a Bengalese finch in the presence of a conspecific song. The results indicate that selective attention to birdsongs within an auditory scene is related to their biological relevance. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Acoustical and perceptual structures of sexually dimorphic distance calls in Bengalese finches (Lonchura striata domestica).

Characterized the physical structure of distance calls by the Bengalese finch (Lonchura striata domestica) and its relation to perception. Distance calls were recorded from 12 female and 12 male Bengalese finches and analyzed; such acoustic parameters as length, bandwidth, and peak frequency were obtained, and differences between sexes on combinations of these parameters were tested and shown to be significant. To assess perceptual salience of acoustic parameters, discrimination of 4 female and 4 male calls was examined. The reaction time (RT) required to discriminate a pair of distance calls was used as a measure of similarity between the 2 calls and analyzed by a multidimensional scaling procedure to find the perceptual dimensions. The results suggest that the sex difference in Bengalese finch distance calls is easily perceived by Bengalese finches and that the males and females were not different in their perception of the calls. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Song learning in brood-parasitic indigobirds Vidua chalybeata: song mimicry of the host species

Brood-parasitic village indigobirds, Vidua chalybeata, were bred in captivity and foster-reared by their normal host, red-billed firefinch, Lagonosticta senegala, or by an experimental foster species, Bengalese finch, Lonchura striata. Male indigobirds reared by Bengalese finches developed the songs of Bengalese finches, and males reared by firefinches developed songs of firefinches. Males copied their foster father only when they had lived with him long after independence (45 days post-fledging), while males separated normally at independence (22-24 days post-fledging) copied songs of other individuals and not songs of their foster father. Males reared by Bengalese finches showed no preference to learn firefinch song over songs of the experimental foster species or other control finch species even when they had lived with firefinches as companions from the time of fledging to independence. Males copied several song themes, acquired the same number of mimicry songs, and acquired their songs at the same age, whether reared by Bengalese finches or by firefinches. When they lived with other indigobirds, the male indigobirds copied mimicry songs of male indigobirds that mimicked the same foster species. We predicted mimicry-song specificity and repertoire size in experimental indigobirds from a hypothesis of an early developmental period when young indigobirds focus their attention on their foster parents, and a later period when they direct their attention to other birds with similar songs. The predictions, based on field observations of wild birds, were that (1) males reared by a novel foster species other than the normal host would learn the song of that foster species, and (2) males that left their foster parents at the normal time of independence would copy the songs of other individuals, including other adult indigobirds that mimicked the same foster species. Begging calls of young indigobirds did not mimic the calls of young firefinches. Indigobirds reared alone, or with young of the normal host or of the experimental foster species, all developed begging calls in adult song that resembled their own begging as nestlings and fledglings, and only males that heard other adult indigobirds with firefinch-mimicry begging developed firefinch begging in their song. The incorporation of the innate begging calls as well as the learned begging calls into adult song, and the modification of the song themes of their individual song models, suggest that song development involves processes in addition to copying the songs of their own foster species and of older adult male indigobirds with songs like their own foster parents. Copyright 1998 The Association for the Study of Animal Behaviour. Copyright 1998 The Association for the Study of Animal Behaviour.     

Song-note discriminations in zebra finches (Taeniopygia guttata): Categories and pseudocategories.

Sturdy, Phillmore, and Weisman (1999) developed a simple, reliable procedure for classifying zebra finch (Taeniopygia guttata) song notes into types using exemplar notes from 4 captive North American laboratory colonies. In the present experiment, zebra finches learned true-category song-note discriminations based on Sturdy et al.'s note-type classification faster than pseudocategory discriminations based on random assortments of the same notes. Also, birds in the true-category discrimination were able to sort notes not heard during training into the same categories as the training notes. This evidence suggests that zebra finches accurately sort conspecific song notes into the same open-ended categories as Sturdy et al.'s human observers. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Conspecific song perception in zebra finches (Taeniopygia guttata)

Adult male and female zebra finches (Taeniopygia guttata), previously trained with operant conditioning to discriminate between conspecific songs, were tested to determine their dependence on 2 properties of songs, the presence of song syllables and the temporal order of songs. The removal of song syllables disrupted discrimination performance but usually only if the stimulus was the bird's own song. All birds initially failed to identify reversed songs correctly, but males relearned discriminations with reversed songs in fewer trials than did females. The results suggest that there are 3 levels of song perception: a bird's own song, other males' songs as processed by males, and songs as processed by females. Each of these levels correlates with the known electrophysiological and neuroanatomical properties of the song system and with the natural history of song.     

Auditory perception of conspecific and heterospecific vocalizations in birds: Evidence for special processes.

Budgerigars (Melopsittacus undulatus), canaries (Serinus canaria), and zebra finches (Poephila guttata castanotis) were tested for their ability to discriminate among distance calls of each species. For comparison, starlings (Sturnus vulgaris) were tested on the same sounds. Response latencies to detect a change in a repeating background of sound were taken as a measure of the perceptual similarity among calls. All 4 species showed clear evidence of 3 perceptual categories corresponding to the calls of the 3 species. Also, budgerigars, canaries, and zebra finches showed an enhanced ability to discriminate among calls of their own species over the calls of others. Starlings discriminated more efficiently among canary calls than among budgerigar or zebra finch calls. Results show species differences in discrimination of species-specific acoustic communication signals and provide insight into the nature of specialized perceptual processes. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Sex differences in audiovisual discrimination learning by Bengalese Finches (Lonchura striata var. domestica).

Both visual and auditory information are important for songbirds, especially in developmental and sexual contexts. To investigate bimodal cognition in songbirds, the authors conducted audiovisual discrimination training in Bengalese finches. The authors used two types of stimulus: an "artificial stimulus," which is a combination of simple figures and sound, and a "biological stimulus," consisting of video images of singing males along with their songs. The authors found that while both sexes predominantly used visual cues in the discrimination tasks, males tended to be more dependent on auditory information for the biological stimulus. Female responses were always dependent on the visual stimulus for both stimulus types. Only males changed their discrimination strategy according to stimulus type. Although males used both visual and auditory cues for the biological stimulus, they responded to the artificial stimulus depending only on visual information, as the females did. These findings suggest a sex difference in innate auditory sensitivity. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Song Perception During the Sensitive Period of Song Learning in Zebra Finches (Taeniopygia guttata).

The sensitive period is a special time for auditory learning in songbirds. However, little is known about perception and discrimination of song during this period of development. The authors used a go/no-go operant task to compare discrimination of conspecific song from reversed song in juvenile and adult zebra finches (Taeniopygia guttata), and to test for possible developmental changes in perception of syllable structure and syllable syntax. In Experiment 1, there were no age or sex differences in the ability to learn the discrimination, and the birds discriminated the forward from reversed song primarily on the basis of local syllable structure. Similar results were found in Experiment 2 with juvenile birds reared in isolation from song. Experiment 3 found that juvenile zebra finches could discriminate songs on the basis of syllable order alone, although this discrimination was more difficult than one based on syllable structure. The results reveal well-developed song discrimination and song perception in juvenile zebra finches, even in birds with little experience with song. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Noradrenergic neurotoxin, N-(2-chloroethyl)-N-ethyl-2-bromobenzylamine hydrochloride (DSP-4), treatment eliminates estrogenic effects on song responsiveness in female zebra finches (Taeniopygia guttata).

Female songbirds use male songs as an important criterion for mate selection. Several studies have reported that female songbirds prefer complex songs to other song types. In a recent study, the authors found that song responsiveness in female zebra finches (Taeniopygia guttata) is strongly modulated by circulating estrogen levels. The behavioral effects of estrogen are often mediated via norepinephrine (NE). The current study administered the noradrenergic neurotoxin, N-(2-chloroethyl)-N-ethyl-2-bromobenzylamine hydrochloride (DSP-4) to estradiol-treated female zebra finches to investigate if estrogenic effects on song responsiveness are mediated via NE. The authors tested song responsiveness of adult female zebra finches for three acoustically different song types--simple, long-bout, and complex--under three treatment conditions, untreated, estradiol-treated, and estradiol + DSP-4-treated. Females only showed differential song responsiveness when treated with estradiol alone, responding more to complex songs. DSP-4 treatment eliminated this differential responsiveness. The results are discussed in the light of evidence from functional, neurochemical, and neuroanatomical studies that suggest that estrogenic effects on song processing might be mediated by NE. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Frequency–range discriminations: Special and general abilities in zebra finches (Taeniopygia guttata) and humans (Homo sapiens).

The acoustic frequency ranges in birdsongs and human speech can provide important pitch cues for recognition. Zebra finches and humans were trained to sort contiguous frequencies into 3 or 8 ranges, based on associations between the ranges and reward. The 3-range task was conducted separately in 3 spectral regions. Zebra finches discriminated 3 ranges in the medium and high spectral regions faster than in the low region and discriminated 8 ranges with precision. Humans discriminated 3 ranges in all 3 spectral regions to the same modest standard and acquired only a crude discrimination of the lowest and highest of 8 ranges. The results indicate that songbirds have a special sensitivity to the pitches in conspecific songs and, relative to humans, have a remarkable general ability to sort pitches into ranges. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Localization of androgen receptor mRNA-containing cells in avian respiratory-vocal nuclei: an in situ hybridization study

Song development and song pattern formation in oscine songbirds are influenced by steroid hormones such as estrogens and androgens, and the control of vocal pattern generation is mediated via a network of interconnected vocal and respiratory nuclei. The main components of the respiratory part of the network are the expiratory and inspiratory premotor nuclei, known as retroambigualis (RAm) and the rostral ventral respiratory group (rVRG), respectively. These respiratory components play an integral role in song production either by providing the expiratory pulses of air required for each and every song syllable, or by controlling inspiration between syllables in the form of minibreaths, and between phrases for major replenishments of air. Here we analyze the distribution of androgen receptors (AR) and estrogen receptors (ER) in the midbrain and hindbrain of male and female zebra finches, and male canaries and green finches, using in situ hybridization with cRNA probes of the zebra finch AR and ER. ERmRNA was not expressed in any of the respiratory-vocal nuclei of the midbrain or hindbrain, but ARmRNA was expressed in the tracheosyringeal motor nucleus (nXIIts) and in RAm and rVRG. The size of the ARmRNA defined RAm and rVRG was similar in male and female zebra finches, but the size of ARmRNA defined nXIIts was slightly sexual dimorphic. Previously undescribed areas of ARmRNA expression outside the respiratory-vocal network in the brain stem were the nucleus semilunaris and layers 10-12 of the optic tectum. AR-mRNA expression in the respiratory-vocal nuclei of adult male songbirds, adult female zebra finches, and juvenile zebra finches suggests that the temporal pattern of learned and unlearned vocalizations is sensitive to androgen-dependent mechanisms mediated by RAm and rVRG.     

Frequency-range discriminations and absolute pitch in black-capped chickadees (Poecile atricapillus), mountain chickadees (Poecile gambeli), and zebra finches (Taeniopygia guttata).

The acoustic frequency ranges in birdsongs provide important absolute pitch cues for the recognition of conspecifics. Black-capped chickadees (Poecile atricapillus), mountain chickadees (Poecile gambeli), and zebra finches (Taeniopygia guttata) were trained to sort tones contiguous in frequency into 8 ranges on the basis of associations between response to the tones in each range and reward. All 3 species acquired accurate frequency-range discriminations, but zebra finches acquired the discrimination in fewer trials and to a higher standard than black-capped or mountain chickadees, which did not differ appreciably in the discrimination. Chickadees' relatively poorer accuracy was traced to poorer discrimination of tones in the higher frequency ranges. During transfer tests, the discrimination generalized to novel tones when the training tones were included, but not when they were omitted. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Sexual preferences in zebra finch (Taeniopygia guttata) males raised by two species (Lonchura striata and Taeniopygia guttata): I. A case of double imprinting.

Examined whether dithering behavior is the result of sexual imprinting on 2 species. When young zebra finch males are exposed to their own species, as well as to Bengalese finches later on, they may court both species; the stability as well as the exclusiveness of the preference was examined. In Exp I, dithering males that had been tested for their preference when adults were subsequently either isolated or given experience with conspecifics. Afterward, the males were tested again. Although preferences appeared to have become more zebra finch directed, especially in males with experience with conspecifics, most males in both groups still courted both species, results indicating that the dithering phenomenon is persistent. In Exp II, whether dithering indicates a double preference or the lack of a specific preference was examined. Dithering males preferred both zebra finches and Bengalese finches over (unfamiliar) white zebra finches and over silverbills. Results suggest that dithering indicates imprinting on both zebra and Bengalese finches. (15 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Developmental determinants of structure in zebra finch song.

Zebra finches (Taeniopygia guttata) possess highly organized species-uniform song structure. The present author explored song determinants by a series of 5 studies in which a total of 85 young Ss were (a) reared in social contact with zebra finch adults, (b) reared in isolation from adult song, (c) deafened early in life, (d) tutored by zebra finch males they could not see, or (e) tutored with sounds other than zebra finch song. The main song determinants appear to be (a) learning, which probably determines song structure accurately for a limited number of generations; (b) inherited neuromotor constraints that specify basic temporal patterning within song; and (c) infusion of developmentally conservative calls and noncall isolate note types into song. Limitations on song development imposed by effector organs are relatively permissive, and the role of inherited auditory specifications (template) is uncertain. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Sex differences in aggressive behavior in zebra finches (Poephila guttata).

Aggressive behavior between pairs of female or male zebra finches (Poephila guttata) was measured before, during, and after presentation of either a female or male finch (the stimulus) in an adjacent cage. Presentation of the stimuli led to marked increases in aggressive behavior for both sexes of Ss, such that presentation of a female stimulus caused an elevation in aggression in male pairs and presentation of a male stimulus caused an elevation in female pairs. These results are interpreted in the context of competition for mates in species, such as zebra finches, that have long-term monogamous pair bonds and biparental care. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Note types, harmonic structure, and note order in the songs of zebra finches (Taeniopygia guttata)..

Zebra finch (Taeniopygia guttata) song notes are acoustically complex, rich in harmonic structure, and variable among birds. This article provides simple, reliable methods for classifying zebra finch song notes into types, for describing the harmonic structure of song notes, and for determining the order of notes in song motifs in samples from 4 captive North American laboratory colonies. Using the note-type classification scheme, 2 observers sorted 90% of readable song notes into 5 types with 94% interobserver agreement. Examination of song-note power spectra revealed that reduced harmonics were a common feature of zebra finch song notes. Finally, an analysis of zebra finches' songs suggests that males produce the notes in their motifs in a consistent but not stereotyped (invariant) order. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Syllable chunking in zebra finch (Taeniopygia guttata) song.

Examined how 61 young zebra finch males copied song from 5 adult tutors. Zebra finch song consists of a string of 5–25 distinct syllables, and these syllables were copied as chunks, or strings of consecutive syllables (modal length?=?3). The silent interval between 2 syllables was copied as part of the syllable after the silence. Copied chunks had boundaries that fell at consistent locations within the tutor's song, marked by a relatively long intersyllable silent period, a transition between call-like and noncall-like syllables, and a tendency for the tutor male to stop his song short. Young males also tended to break their songs off at the bondaries of the chunks they had copied. Chunks appear to be an intermediate level of hierarchy in song organization and to have both perceptual (syllables were learned as part of a chunk) and motor (song delivery was broken almost exclusively at chunk boundaries) aspects. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Temporal and spectral sensitivity of complex auditory neurons in the nucleus HVc of male zebra finches

Complex vocalizations, such as human speech and birdsong, are characterized by their elaborate spectral and temporal structure. Because auditory neurons of the zebra finch forebrain nucleus HVc respond extremely selectively to a particular complex sound, the bird's own song (BOS), we analyzed the spectral and temporal requirements of these neurons by measuring their responses to systematically degraded versions of the BOS. These synthetic songs were based exclusively on the set of amplitude envelopes obtained from a decomposition of the original sound into frequency bands and preserved the acoustical structure present in the original song with varying degrees of spectral versus temporal resolution, which depended on the width of the frequency bands. Although both excessive temporal or spectral degradation eliminated responses, HVc neurons responded well to degraded synthetic songs with time-frequency resolutions of approximately 5 msec or 200 Hz. By comparing this neuronal time-frequency tuning with the time-frequency scales that best represented the acoustical structure in zebra finch song, we concluded that HVc neurons are more sensitive to temporal than to spectral cues. Furthermore, neuronal responses to synthetic songs were indistinguishable from those to the original BOS only when the amplitude envelopes of these songs were represented with 98% accuracy. That level of precision was equivalent to preserving the relative time-varying phase across frequency bands with resolutions finer than 2 msec. Spectral and temporal information are well known to be extracted by the peripheral auditory system, but this study demonstrates how precisely these cues must be preserved for the full response of high-level auditory neurons sensitive to learned vocalizations.