Song Quality Research Articles

The Effect of Polychlorinated Biphenyls on the Song of Two Passerine Species

Polychlorinated biphenyls (PCBs) are synthetic chemical pollutants with demonstrated detrimental toxic and developmental effects on humans and wildlife. Laboratory studies suggest that PCBs influence behavior due to their effects on endocrine and neurological systems, yet little is known about the behavioral consequences of sublethal PCB exposure in the field. Additionally, specific PCB congener data (in contrast to total PCB load) is necessary to understand the possible effects of PCBs in living organisms since number and position of chlorine substitution in a PCB molecule dictates the toxicity and chemical fate of individual PCB congeners. We non-lethally investigated total PCB loads, congener specific PCB profiles, and songs of black-capped chickadees (Poecile atricapillus) and song sparrows (Melospiza melodia) along a historical PCB gradient at the Hudson River in New York State. Our results indicate that black-capped chickadees and song sparrows have higher total blood PCBs in regions with higher historic PCB contamination. The two bird species varied substantially in their congener-specific PCB profiles; within sites, song sparrows showed a significantly higher proportion of lower chlorinated PCBs, while black-capped chickadees had higher proportions of highly chlorinated PCBs. In areas of PCB pollution, the species-specific identity signal in black-capped chickadee song varied significantly, while variation in song sparrow trill performance was best predicted by the mono-ortho PCB load. Thus, PCBs may affect song production, an important component of communication in birds. In conclusion, we suggest that the ramifications of changes in song quality for bird populations may extend the toxic effects of environmental PCB pollution.

Differential allocation in relation to mate song quality in the Bengalese finch

Postmating sexual selection plays an important part in the evolution of secondary sexual characters. Based on differential allocation theory that predicts biased reproductive investment of females depending on the attractiveness of mates, a number of previous studies have shown that egg production is related in various ways to ornamental sexual traits of males, but evidence for behavioural sexual traits is less abundant. In this study we examine such maternal effects in relation to birdsong. Because the Bengalese finch is a monomorphic songbird, courtship song serves a key role in mate choice. To take into account individual female differences in egg production performance, we sequentially paired naïve, captive, female Bengalese finches to two different males, and investigated if their reproductive investment (clutch size, egg mass and hatchling sex ratio) was related to the song traits of their mates. We found that clutch size and egg mass were highly repeatable within individual females while sex ratio was not. Despite the inflexibility of egg mass within each female, egg mass increased when females were mated to males with longer songs. In addition, we found a non-significant weak tendency toward male-biased sex ratio in relation to longer song duration of mates. Our findings suggest that females mated to better mates adjusted their reproductive investment by producing heavier eggs and possibly offspring of the more costly sex.

Norepinephrine inhibition in juvenile male zebra finches modulates adult song quality

During development, male zebra finches learn a song that they eventually use in courtship and defense of nest sites. Norepinephrine (NE) is important for learning and memory in vertebrates, and this neuromodulator and its receptors are present throughout the brain regions that control song learning and production. The present study used the neurotoxin N-(2-chloroethyl)-N-ethyl-2-bromobenzylamine hydrochloride (DSP4) to reduce brain levels of NE in juvenile males. This manipulation inhibited the development of quality songs, with some birds producing syllables that were unusually long and/or contained frequencies that were predominantly higher than normal. These results suggest that NE is important for the acquisition of typical song.

Social networks and the development of social skills in cowbirds

The complex interrelationships among individuals within social environments can exert selection pressures on social skills: those behaviours and cognitive processes that allow animals to manipulate and out-reproduce others. Social complexity can also have a developmental effect on social skills by providing individuals with opportunities to hone their skills by dealing with the challenges posed in within-group interactions. We examined how social skills develop in captive, adult male brown-headed cowbirds (Molothrus ater) that were exposed to differing levels of 'social complexity' across a 2-year experiment. After each year, subjects housed in groups with dynamic social structure (where many individuals entered and exited the groups during the year) outcompeted birds who had been housed in static groups. Exposure to dynamic structure subsequently led to substantial changes to the social networks of the home conditions during the breeding season. Static groups were characterized by a predictable relationship between singing and reproductive success that was stable across years. In dynamic conditions, however, males showed significant variability in their dominance status, their courting and even in their mating success. Reproductive success of males varied dramatically across years and was responsive to social learning in adulthood, and socially dynamic environments 'trained' individuals to be better competitors, even at an age when the development of many traits important for breeding (like song quality) had ended.

The use of multimodal communication in mate choice decisions by female house crickets, Acheta domesticus

Females of various animal taxa benefit from mating with large males, and size is often communicated through different signal modalities. In male house crickets, Acheta domesticus, size is positively correlated with heritable immunocompetence and the proportion of three-pulse chirps in the male’s calling song. Although females can use these acoustic signals to choose desirable males, little is known about how these acoustic signals interact with other signal modalities. We investigated whether females prefer large males in the absence of acoustic signals. In tournament style two-choice tests, wing-clipped males that were mounted first on consecutive trials had a significantly larger mass on average than wing-clipped males that were not mounted first in both trials. We also used 100 two-choice tests to verify female acoustic preferences. Female house crickets spent significantly more time near speakers playing the calling song of a large male than the calling song of a small male. Finally, we pre-exposed females to a calling song recording from a small or large male and then presented the female with a small or large wing-clipped male to determine whether calling song or nonacoustic signals were weighed more heavily by females. Females had a lower latency to mount when presented with a large male, regardless of the quality of the calling song to which females had been pre-exposed. However, a high-quality calling song still decreased females’ latency to mount small males. These results suggest that females assess size using long-range acoustic signals, but also reassess size using more proximate nonacoustic signals.

Using Science Songs to Enhance Learning: An Interdisciplinary Approach

Music is recognized as an effective mode of teaching young children but is rarely used in university-level science courses. This article reviews the somewhat limited evidence on whether and how content-rich music might affect college students' understanding of science and offers practical suggestions for incorporating music into courses. Aside from aiding memorization, songs may potentially improve learning by helping students feel relaxed and welcome in stressful settings, engaging students through multiple modes (verbal vs. nonverbal) and modalities (auditory vs. visual vs. kinesthetic) simultaneously, challenging students to integrate and “own” the material through the medium of song lyrics, and increasing students' time on task outside of class through enjoyable listening or songwriting assignments. Students may produce content-rich songs of good quality if given sufficient assistance and encouragement by instructors and peers. The challenges ahead include 1) defining the circumstances in which music is most likely to promote learning and 2) developing rubrics for evaluating the quality of songs.

Early Exposure to 2,2′,4,4′,5-Pentabromodiphenyl Ether (BDE-99) Affects Mating Behavior of Zebra Finches

2,2',4,4',5-Pentabromodiphenyl ether (BDE-99) is a brominated flame retardant congener that has pervaded global food chains, being reported in avian egg and tissue samples throughout the world. Its effects on birds are not well known, but there is evidence in exposed mammals that it directly mediates and causes neurotoxicity, alters thyroid hormone homeostasis, and lowers sex steroid hormone concentrations. In birds, those processes could disrupt the song-control system and male mating behavior. In this study, the effects of nestling exposure to environmentally relevant levels of BDE-99 were assessed in a model songbird species, the zebra finch (Taeniopygia guttata). A tissue residue study in which zebra finch nestlings were orally exposed to 0, 2.5, 15.8, or 50.7 ng BDE-99/g body weight (bw) per day over the 21-day nesting period validated dosing methods and confirmed dose levels were environmentally relevant (332.7 ± 141.0 to 4450.2 ± 1396.2 ng/g plasma lipid). A full-scale study exposing nestlings to 0, 2.5, 15.8, 50.7, or 173.8 ng BDE-99/g bw/day was carried out to investigate long-term effects of BDE-99 on the adult song-control nuclei volumes, song quality, and male mating behavior. Early exposure to BDE-99 had significant effects on male mating behavior and the response of clean experienced females to exposed males. There was no effect on male song-control nuclei or song quality, and there were nondose-dependent effects on female song-control nuclei. The results demonstrate that early exposure to environmentally relevant levels of BDE-99 affects the behavior of zebra finches.

Variation in enkephalin immunoreactivity in the social behavior network and song control system of male European starlings (Sturnus vulgaris) is dependent on breeding state and gonadal condition

Many temperate zone songbird species exhibit marked seasonal variation in song quality as well as in the motivation to sing. Two brain systems are known to mediate such annual variation in song quality and motivation: (1) the song control system (SCS), and (2) the social behavior network (SBN), respectively. How these two circuits interact to produce changes in singing behavior is not well understood. The opioid enkephalin is expressed in both the SCS and SBN and may function to modulate song quality in a socially relevant manner. Using immunocytochemistry, we examined variation in enkephalin immunoreactivity (ENK-ir) in male European starlings (Sturnus vulgaris) that were in breeding conditions (i.e. photostimulated) or non-breeding conditions (i.e. photorefractory). We also included a group of castrated photostimulated males to investigate the relationship between gonadal steroids and ENK-ir. ENK-ir in the preoptic area (POA) and lateral septum (LS) was greater in photostimulated intact birds as compared to photorefractory males, but not in other regions within the SBN. There was a significant difference in ENK-ir in two forebrain song nuclei, HVC and the lateral nucleus of the anterior medial nidopallium (lMAN), with lower expression in photostimulated intact as compared to photorefractory birds. ENK-ir did not change across breeding conditions in the Nucleus Interface (NIf). After accounting for the volumetric change in HVC and lMAN, the pattern of ENK-ir remained greater in photorefractory compared to intact photostimulated starlings. We propose that the observed regulation of ENK-ir in the POA and LS may be related to seasonal changes in the motivation to engage in singing behavior, while the change in ENK-ir in the song system are associated with the quality of the song produced. Thus seasonal changes in a single neuromodulatory system can have very different functional effects based on the neuroanatomical specificity of its expression.

Song bout length is indicative of spatial learning in European starlings

Female songbirds are attracted to male song, and song may honestly signal male quality. Song is a phenotypic expression of a complex learned behavior and therefore could be indicative of other cognitive abilities. Stressful conditions during early development are known to adversely affect the development of the mammalian and avian brain, and recent evidence suggests a positive association between song quality and learning ability. However, prior studies have not assessed how early-life stress affects both general cognitive functioning and song learning. We subjected nestling- and juvenile-caught European starlings (Sturnus vulgaris) to either an ad libitum or food-restricted diet until approximately 90 days of age. As adults, birds’ cognitive abilities were assessed via spatial foraging and social learning tasks, while controlling for the effects of neophobia. Song learning was assessed in undirected and directed singing contexts. We found that birds fed the ad libitum diet had significantly longer song bouts in both singing contexts, made fewer errors in the spatial foraging task, but performed worse on the social learning task than food-restricted birds. Overall, song performance only correlated with performance on the spatial foraging task: Males with longer mean song bouts in the directed singing context committed fewer errors. These data suggest that the neural structures supporting song and spatial abilities are both affected by nutritional stress during development. Female starlings are attracted to longer song bouts and may thus use song bout length to infer spatial learning abilities of potential mates.

“And every day there is music”: Folksong Roots and the Highway Chain Gang in The Ballad of the Sad Café

“And every day there is music”: Folksong Roots and the Highway Chain Gang in The Ballad of the Sad Café Daniel Patrick Barlow (bio) It is an interesting thought that perhaps all the music that Negroes in America have made might have been quite different if the work that they were brought here to do had been different. Suppose Negroes had been brought to this country to make vases or play basketball. How might the blues have developed then from the impetus of work songs geared to those occupations? —Amiri Baraka, Blues People Question: When is a ballad not a ballad? Answer: When it has no tune. —Bertrand H. Bronson, The Traditional Tunes of the Child Ballads This essay explores the utility and musicality of the ballad relative to Carson McCullers’s The Ballad of the Sad Café. Most often, this novella is perceived as a literary ballad, even if perfunctorily so. Joseph Millichap’s prominent analysis is one such example, wherein he states that “the description of her narrative as a ballad, so obviously presented in the title, provides a key to understanding which unlocks the novella’s difficulties of literary mode, point of view, characterization, and plot structure” [End Page 74] (329). Following through on this observation, Mary Ann Dazey offers a thorough and concise analysis of the novella in comparison with stanzaic ballad formulations, developing an important conclusion about the narrative structure: “the ballad voice tells the story, and the second voice provides the sad background music” (Dazey 39). This perspective is consistent with Virginia Carr’s biography of McCullers, in which the details of her musicianship come to the fore. As Carr writes, McCullers “later attributed her excellent sense of form and structure to her study of music” (26). Though her plans for concert performance were abandoned in 1932 after a debilitating bout of rheumatic fever, Carr explains that McCullers “had no regrets about losing music as the major dimension in her life . . . for she still listened and thrilled to it, even though she no longer played it herself” (492). With this added biographical reason, The Ballad of the Sad Café might be approached with an eye—or rather an ear—for its ballad-like qualities. There is, however, a conflict between interpretations of the novella as ballad and of the significance of its ending, “The Twelve Mortal Men.” There we are privy to the labor and song of a chain gang through the voice of the narrator, but read only of the nature of their cries and rhythm of their picks. Their lyrics being omitted, we are left with an enigmatic portrait of the American work song. Compounding the matter, clues as to why the chain gang appears at all are ostensibly nebulous. This coda of rather bewildering intent has given rise to a dynamic variation in critical responses, even to the point of virulent debate. My argument is that analyses of the novel’s utility as a ballad are incomplete. The significant evidence available to enhance our understanding of this point situates my argument among the aforementioned interpretations, but at the same time incorporates fundamental issues of the novella that critics have for the most part neglected. Among these are the pervasive, albeit subtle, musicality of The Ballad of the Sad Café (hereafter TBSC ) and the historical qualities of ballads and American work songs most pertinent to the text. Moreover, taking this musicological approach allows for a secure underscoring of connections between the coda and the central narrative. Through this approach we will find that the song of the chain gang pervades the text more so than heretofore considered, consequently revealing that TBSC bears qualities of song that significantly expand its utility as a “ballad” per se. Properly, the ballad is a song intended to be danced to, as in the Italian ballare, to dance (“Ballad” 2), or the French ballade, a dancing-song (“Ballad” 1). Early musical ballads from the twelfth century took [End Page 75] their form mostly in lyrical dance-songs, but their emphasis on dance diminished. This may have contributed to the term’s more generalized sixteenth-century application as “anything singable, simple, popular in style, and for solo vocalists...

Neural coding of syntactic structure in learned vocalizations in songbirds

Birdsong is an important sexually selected trait, and its acoustic features are socially transmitted in the process of song learning. The preference of some female songbirds for song complexity as measured by repertoire size has driven the evolution of many song traits and song-learning programs in males. If juvenile birds adopt the attractiveness of model birds by copying their repertoires, tutor choice in the early song-learning period should be crucial for future reproductive success. Thus, we hypothesized that the song quality of tutors influences the tutor choice of chicks in the Bengalese finch, Lonchura striata var. domestica. Each subject chick was reared by a foster pair in an individual breeding cage. At around the fledging period, we introduced another unrelated adult male (subtutor) into each cage to simulate the natural social environment in which chicks have opportunities to hear the songs of nonfather males after fledging. Subject chicks learned from both tutors when the total note repertoire size of the two models was small; they tended to learn from the subtutor when the father had a smaller note repertoire size. The acquired note repertoire size was not affected by whether subjects learned songs from the foster father or not. Song learning from the subtutor contributed to a larger note repertoire. Observed patterns in tutor choice, in particular song learning from a subtutor, could be an adaptive strategy that helps chicks compensate for exposure to smaller repertoire size in models.

Wings of Poesy: Keats's Birds

This essay examines Keats's engagement with birds in his poetry. Addressing poems ranging from 'Imitation of Spenser' (1814) to 'To [Fanny]' (1819), it illustrates the significance of a variety of birds to Keats's poetics, and in doing so reinforces the poet's position in a tradition of bird-inspired writing. As the following argues, Keats appreciates birds not simply as creatures of beauty, but also for their imaginative and symbolic value: through their qualities of flight and song especially, Keats's birds are shown to be not merely agents of the natural world, but also, to a degree, of poetry itself.

Change in offspring sex ratio over a very short season in Lincoln's Sparrows: the potential role of bill development

The sex ratios of offspring are targets of natural selection that can affect parental energy expenditure and fitness, adult sex ratios, and population dynamics. Parents may manipulate offspring sex ratios based on sex differences in potential reproductive success. In Lincoln’s Sparrows (Melospiza lincolnii), male bill shape is associated with the quality of songs, and song quality predicts female preferences in a reproductive context.Males and females that hatch later relative to brood mates or later in the breeding season tend to develop bill shapes that are, for males, associated with low-quality song. Because females do not sing and do not experience this selection pressure, we predicted that the sex of offspring produced late relative to their brood mates or relative to the season should be biased toward females. Using a molecular technique to sex nestlings, we found no effects of hatching order or any interaction between date of clutch initiation and hatching order on offspring sex. However, we found a seasonal decline in the proportion of male offspring, from approximately 0.8 at the beginning to 0.4 at the end of a clutch initiation season only 19 d in duration. To our knowledge, this is the shortest period over which the offspring sex ratio has been shown to change in a bird population. Moreover, these findings are consistent with the hypothesis that sex differences in the potential attractiveness of offspring ultimately influence offspring sex ratios.

Social performance reveals unexpected vocal competency in young songbirds

Vocal ontogeny in songbirds provides a good model for understanding how complex motor behavior, including speech, is learned. For birdsong, as for other motor learning, it has generally been assumed that a subject's motor output at any point during learning represents what the subject has learned to produce by that time. Here, we show, however, that juvenile zebra finches partway through song learning, singing immature song, are capable of producing song with much more mature properties, depending on the behavioral context. In these birds, we were able to elicit courtship (female-directed) song, which young birds normally sing infrequently, and to compare it with the alone or "undirected" song (Undir) predominantly produced during learning as well as with the same bird's subsequent adult song. We found that the juvenile courtship song was much less variable than the immature Undir and as stereotyped as the adult song produced after a further month of practice. More strikingly, the juvenile courtship song was also acoustically much more similar than Undir to the adult song. This finding demonstrates that the Undir that juvenile birds usually produce underestimates the extent of learning and that song structure is learned faster than previously thought. Moreover, the rapid improvement in song quality in response to external social cues supports the idea that courtship singing is a state of motor "performance," in which the bird selects the best variants of the song learned during singing alone, and suggests that such performance states can reveal unappreciated progression of learning.

Developmental stressors that impair song learning in males do not appear to affect female preferences for song complexity in the zebra finch

A number of recent studies have provided evidence that the environmental factors experienced during development contribute to variation between females in the direction and strength of their mating preferences. The developmental stress hypothesis suggests that the complex male songs of many songbirds and female preferences for those complex songs have evolved because song quality reflects how well an individual was able to cope with suboptimal developmental conditions. In this study, we tested whether female preferences for song complexity are affected by developmental stress. Female zebra finches, Taeniopygia guttata, were raised under conditions of nutritional stress or control conditions. In adulthood, their song preferences were tested in an operant setup where females could trigger playback of song recordings by landing on different perches. The subjects could choose between pairs of songs that were digitally manipulated to ensure that they varied only in the number of syllables in the song. Across all subjects, there was a significant preference for the more complex song of the song pair, but there was no difference between the treatment groups in the direction or strength of their preference. These results suggest that adverse developmental conditions do not impair females' ability or motivation to discriminate between songs on the basis of complexity and thus to obtain information about potential mates' developmental history. Copyright 2011, Oxford University Press.

Eavesdropping on Male Singing Interactions Leads to Differential Allocation in Eggs

AbstractFemales invest differently in their eggs depending on the quality of their mates. In oscines, female investment is influenced by the quality of male song. In domestic canaries Serinus canaria, as well as in black‐capped chickadees Poecile atricapillus, females pay attention not only to the intrinsic quality of male song but can also gather information, by eavesdropping on male–male singing interactions, on the relative quality of males. During these interactions, overlapping the song of the rival is more threatening than alternating. Moreover eavesdropping female canaries have been shown to prefer the overlapping song rather than the overlapped song. The present study was designed to assess the effect of the information gathered by eavesdropping on female investment in eggs. First, we broadcasted overlapping interactions to female canaries. Then, we broadcasted to each female one of the two songs previously heard and collected eggs. Females exposed to overlapping songs laid eggs with greater yolk ratio than females exposed to overlapped songs. In contrast, yolk testosterone quantity and concentration were not affected by the treatment. Moreover, we found a variation between eggs with regard to the testosterone deposited in yolk: both quantity and concentration increased with laying order. Our results suggest that female canaries use information gathered by eavesdropping to differentially allocate resources into the eggs. They suggest that singing interactions could influence chick quality via female investment.

Female response to song reflects male developmental history in swamp sparrows

One explanation for why female songbirds attend to male song is that the quality of a male's song is associated with the quality of his developmental history. We tested this hypothesis by playing back to female swamp sparrows (Melospiza georgiana) songs recorded from males of either inferior or superior developmental histories, as assessed by their rates of mass gain during the first 18 days post-hatching. Females showed significantly higher levels of courtship display in response to songs of males with superior growth than to songs of males with inferior growth. Out of nine song traits measured, only song duration correlated with variation in female response; duration was also the only trait that differed significantly in univariate comparisons between the superior growth songs and the inferior growth songs. In a multivariate analysis, however, inferior growth songs were best discriminated from superior growth songs by combining three song traits: trill rate, stereotypy, and the number of notes per syllable. We suggest that early developmental stress degrades song in many small ways, and that it is the cumulative effect of the resulting deficits that explains lower female response.

A Novel Model for Examining Recovery of Phonation After Vocal Nerve Damage

Recurrent laryngeal nerve injury remains a dominant clinical issue in laryngology. To date, no animal model of laryngeal reinnervation has offered an outcome measure that can reflect the degree of recovery based on vocal function. We present an avian model system for studying recovery of learned vocalizations after nerve injury. Prospective animal study. Digital recordings of bird song were made from 11 adult male zebra finches; nine birds underwent bilateral crushing of the nerve supplying the vocal organ, and two birds underwent sham surgery. Songs from all the birds were then recorded regularly and analyzed based on temporal and spectral characteristics using computer software. Indices were calculated to indicate the degree of similarity between preoperative and postoperative song. Nerve crush caused audible differences in song quality and significant drops (P<0.05) in measured spectral and, to a lesser degree, temporal indices. Spectral indices recovered significantly (mean=43.0%; standard deviation [SD]=40.7; P<0.02), and there was an insignificant trend toward recovery of temporal index (mean=28.0%; SD=41.4; P=0.0771). In five of the nine (56%) birds, there was a greater than 50% recovery of spectral indices within a 4-week period. Two birds exhibited substantially less recovery of spectral indices and two birds had a persistent decline in spectral indices. Recovery of temporal index was highly variable as well, ranging from persistent further declines of 45.1% to recovery of 87%. Neither sham bird exhibited significant (P>0.05) differences in song after nerve crush. The songbird model system allows functional analysis of learned vocalization after surgical damage to vocal nerves.

Female Lincoln's sparrows modulate their behavior in response to variation in male song quality

Sexually reproducing organisms should mate with the highest quality individuals that they can. When female songbirds choose a mate, they are thought to use several aspects of male song that reflect his quality. Under resource-limited environmental conditions, male Lincoln's sparrows (Melospiza lincolnii) vary among one another in several aspects of song quality, including song length, song complexity, and trill performance. In a 2-pronged approach, we tested whether variation in song quality of male Lincoln's sparrows influences the behavior of females that are in a reproductive-like state. Over two trials, we exposed females to songs from the high and low ends of the distribution of naturally occurring song quality variation and found a higher level of behavioral activity in females exposed to high-quality songs, especially when they had first been exposed to low-quality songs. We also examined female phonotaxis toward antiphonally played songs with experimentally elevated and reduced trill performance and found that females moved preferentially toward the songs with elevated trill performance. Contrary to most studies investigating the behavioral responses of wild, female songbirds to variation in male song, we obtained our results without administering exogenous estradiol, which can artificially perturb the female's physiology. Our results demonstrate that the behavior of female Lincoln's sparrows is modulated by the quality of male songs to which they are exposed and that trill performance plays a significant role in this behavioral modulation. Furthermore, as the order of song quality presentation matters, it appears that recent song experience also influences female behavior.

Female Lincoln's sparrows modulate their behavior in response to variation in male song quality

Female Lincoln's sparrows modulate their behavior in response to variation in male song quality