Numerous scholars have observed that Don McKay’s poetry is profoundly musical and particularly attentive to the sounds of birds. However, it has not been examined how musicology can illuminate McKay’s use of birdsong. This thesis addresses McKay’s representation of birdsong by drawing upon musicology, acoustic ecology and ecocriticism. The first chapter examines McKay’s metaphoric and mimetic representations of birdsong. The second chapter explores how McKay uses birdsong to create acoustic spaces within the text. The third chapter probes McKay’s treatment of the physiological processes behind human and avian vocalizations. By defamiliarizing and pushing the boundaries of our language, McKay exposes the epistemological limitations of human language and challenges the species boundary. My hope is that extended attention to the musicality of McKay’s poetry will allow for a fuller appreciation of his treatment of bird vocalizations as songs that extend human language and explore what it means to be human.

Similar to the development of speech in human infants, song learning in juvenile songbirds starts with memorization of adult vocalizations. Young birds develop their own song as a replica of a memorized adult song model through trial and error learning through abundant vocal practice. The internal model of this adult song, termed the ‘template’ is therefore central for guiding the process of vocal learning. However, even the most fundamental aspects of the template, such as when, where and how it is encoded in the brain, remain poorly understood. This dissertation attempts to define a paradigm where the onset of vocal learning and template formation can be time-locked to a small window of exposure to the tutor song. Using this paradigm, I further characterize the molecular changes accompanying the initial phase of vocal learning. The work described here shows that, in the zebra finch, template encoding can be time locked to, on average, a two-hour period of juvenile life and based on just 75 seconds of cumulative tutor song exposure. Rapid changes in vocal output induced by this exposure can be used as markers for predicting the future success of song imitation. To investigate the brain regions involved in this initial phase of vocal learning, a new approach was developed to interrogate global patterns of activity induced gene expression. Statistical parametric mapping, a method used for analysis of functional activity, was adapted to analyze regional activation across 3D reconstructions of whole brain gene expression maps. Using this approach, regions engaged at different stages of vocal learning were identified. To track the molecular mechanisms underlying these activation patterns, changes in the transcriptome of specific brain nuclei were analyzed as the young males undergo rapid changes in the vocal output in response to training. Significant changes in gene expression patterns were detected with divergent gene expression patterns across individual brain regions. The behavioral and molecular tools developed here present an important advance for understanding how the template is instantiated in the songbird brain.

Many species-specific sensorimotor behaviors, such as speech in humans, emerge from the interplay between genetically defined developmental programs and sensory experience. How these processes interact during learning to shape motor circuits is not well understood. The zebra finch (Taeniopygia guttata), an oscine bird that learns to imitate the song of its tutor (usually the father), provides a uniquely tractable model for exploring this question. Song learning in zebra finches takes place during a discrete three-month period during which male juveniles progress from producing highly variable rudimentary sounds that are noisy and unstructured, to a highly stereotyped imitation of their tutor's song. Here I characterize learning-related changes in the functional connectivity within a motor cortex-analogue brain area (RA) that control song production.

The question of how honesty is maintained in animal communication is a perplexing one, especially in the context of aggressive communication, in which the interests of signalers and receivers are opposed. Relevant information for receivers in aggressive interactions includes the fighting ability of the signaler and its likelihood of attack. Signalers may, however, benefit from manipulation of signals to exaggerate this information. To address questions of signal honesty, this dissertation investigates the use of a performance signal in the song of swamp sparrows (Melospiza georgiana). Performance signals are ones that are physically demanding to perform and that therefore reveal the signaler’s physical ability. The particular measure of vocal performance examined here is vocal deviation, which refers to the ability of birds to produce trilled songs approaching a performance boundary defined by the tradeoff between song trill rate (the rate at which elements of a song are repeated) and frequency bandwidth (the range of frequencies encompassed in a song). Three questions regarding the adaptive significance of vocal performance were investigated in the swamp sparrow 1) whether vocal performance is used as a signal in male-male communication, 2) whether vocal performance should be classified as an index signal of male quality, and 3) whether vocal deviation serves as a signal of aggressive intent. Results from four studies indicate that vocal performance plays a role in male-male signaling. Signalers appear to use vocal performance as a signal and receivers attend to differences in vocal performance. Evidence also indicates that vocal performance can be classified as an index signal, because males are constrained in their ability to produce high performance song and high vocal performance is correlated with aspects of male quality, such as age and size. Finally, this dissertation does not support classification of vocal performance as a signal of aggressive intent, because vocal performance fails to predict aggressive escalation.

Speech, writing, and tool-use are all prime examples of everyday learned motor skills that together with dance, music, and sports performance represent the full glory of human cultural expression afforded by dexterous digits, limbs, and bodies. Learning to subconsciously move parts of our body is an underappreciated function of the brain. This dissertation aims to illuminate this process through a series of studies using the zebra finch as a model system. It addresses two major questions. First, what level of modularity is involved in motor learning? Specifically, can we decompose complex learned skills, such as the zebra finch song, into their distinct components such as spectral and temporal aspects? And if so, how independent are these various aspects of motor skill learning and execution from one another? Second, to what degree are the basal ganglia, essential and phylogenetically conserved parts of the motor system, involved in different aspects of motor skill learning? In Chapter 1 of this dissertation, I describe the complex learned vocalization of the zebra finch as a model for understanding these questions, highlighting the use of a rapid and well-controlled learning paradigm termed conditional auditory feedback (CAF). In Chapter 2, using CAF, focal lesions and recordings, I test the role of a songbird basal ganglia pathway in distinct aspects of motor learning. I find that the basal ganglia pathway is necessary for learning spectral but not temporal aspects of the song whereas a pre-motor cortical area encodes changes in the temporal but not spectral structure, suggesting a modularity in birdsong motor learning. In Chapter 3, I infer the mechanisms underlying the basal ganglia-independent temporal learning. Further CAF experiments demonstrate that the nervous system is capable of flexibly modifying temporal structure in one part of the song without affecting the timing in the rest of the song, uncovering yet another level of modularity in encoding song structure. Chapters 2 and 3 provide evidence for the modularity in learning the mean spectral and temporal structure. However, motor performance is also characterized by its trial-to-trial variability around the mean. In Chapter 4, I describe CAF experiments to interrogate the neural basis underlying changes in variability around a mean. I show that spectral variability can be modulated in a very specific manner and independently in different parts of the song. I show that this temporally-specific modulation of variability is mediated by the basal ganglia. Overall, the dissertation suggests that complex motor skills emerge from basic functional modules that independently learn, modulate, and control distinct aspects of learned motor output.

Sequences of stereotyped actions are central to the everyday lives of humans and animals, from the kingfisher's dive to the performance of a piano concerto. Lashley asked how neural circuits managed this feat nearly 6 decades ago, and to this day it remains a fundamental question in neuroscience. Toward answering this question, vocal performance in the songbird was used as a model to study the performance of learned, stereotyped motor sequences. The first component of this work considers the song motor cortical zone HVC in the zebra finch, an area that sends precise timing signals to both the descending motor pathway, responsible for stereotyped vocal performance in the adult, and the basal ganglia, which is responsible for both motor variability and song learning. Despite intense interest in HVC, previous research has exclusively focused on describing the activity of small numbers of neurons recorded serially as the bird sings. To better understand HVC network dynamics, both single units and local field potentials were sampled across multiple electrodes simultaneously in awake behaving zebra finches. The local field potential and spiking data reveal a stereotyped spatio-temporal pattern of inhibition operating on a 30 ms time-scale that coordinates the neural sequences in principal cells underlying song. The second component addresses the resilience of the song circuit through cutting the motor cortical zone HVC in half along one axis. Despite this large-scale perturbation, the finch quickly recovers and sings a near-perfect song within a single day. These first two studies suggest that HVC is functionally organized to robustly generate neural dynamics that enable vocal performance. The final component concerns a statistical study of the complex, flexible songs of the domesticated canary. This study revealed that canary song is characterized by specific long-range correlations up to 7 seconds long-a time-scale more typical of human music than animal vocalizations. Thus, the neural sequences underlying birdsong must be capable of generating more structure and complexity than previously thought.

Mionectes oleagineus (Aves, Tyrannidae) is a small, sexually monomorphic, lek breeding bird. The behaviour and mating system of this species were studied on Costa Rica's Osa Peninsula over two years. In this thesis I ask three questions: 1) What kind of social organization does M. oleagineus exhibit? 2) Does habitat influence male display dispersion? and 3) What is the function of song in attracting mates and in male-male interactions? In Chapter 2, I describe M. oleagineus' social organization. There were three categories of males: territory owners, satellites and floaters. The latter 2 categories were non-territorial and represented half of the male population. I describe interactions between displaying males and visitors to their territories, including courtship display and aggressive interactions between males. Male display dispersion was highly variable in the study area, including classical leks, in which territories shared contiguous boundaries, an exploded lek, where the territories did not share boundaries, and solitary display territories. In Chapter 3, I test the hypothesis that the number of males that can settle in an area, and their subsequent display dispersion, is determined by the availability and dispersion of suitable habitat. Discriminant function analysis of measures of vegetation structure from both territories and non-territory sample plots showed that territory habitat could be distinguished from non-territory habitat. Eleven percent of the sample plots were described as suitable habitat in the analysis. Given that half the male population is non-territorial, the existence of unoccupied, suitable habitat makes it unlikely that habitat availability determines the number of males settling, or their display dispersion. The major occupation of males on their display territories is singing. In Chapter 4, I investigate the function of song for M. oleagineus using behavioural observation and an experiment involving temporary muting. Males which sang at higher rates received more visitors of both sexes. The territories of most muted territorial males were rapidly usurped by other males. Two of the muted males regained their territories upon regaining the ability to sing. This study is the first to directly demonstrate a key role for song in male-male interactions on leks. It also provides evidence that females use song in mate assessment. / Science, Faculty of / Zoology, Department of / Graduate

Social information affects the movement decisions of animals and is often an essential factor in habitat selection. Social information should be especially relevant to long-distance migrating birds that navigate over long distances through unfamiliar habitats to find resources to survive. This information likely varies in both availability and importance at the different spatial scales relevant to migrating birds. Using the common yellowthroat as a case study, I tested whether cues might be available in the songs of locally breeding birds at the continental, within-site, and within-territory scales. At the continental scale, I described the geographic variation in song among genetic groups and subspecies, which may provide useful information for migrants navigating across the continent. I found differences in song structure including the duration of silences between notes, number of notes, and bandwidths which might provide cues. Additionally, bandwidth was related to habitat density. At the within-site scale, I tested whether there is a relationship between song, habitat structure, habitat quality, bird size, and bird quality. I found no evidence that song variation is an available source of information about habitat type or quality to migrants exploring habitat variation at the within-site scale. At the same scale, I tested whether migrating common yellowthroats use the presence of song to find habitat by broadcasting song recordings in suitable and unsuitable habitat patches, but did not lure any migrants. However, when I compared the distance between local singing males and the capture locations of migrant common yellowthroat in a passive mist-netting array to the distances expected by chance, I found that migrants were further away from singing local males than expected, perhaps to avoid costly aggressive interactions. At the within-territory scale, I tested whether a singer's location is predictive of microhabitat structure or food abundance, and whether song rate or duration is predictive of a local male's activities. I found that the location of a singing bird may provide migrants with information about the location of food and structurally denser habitat. Song variation may also predict the likelihood of attack should a migrant intrude in the local male's territory.

The closely related species pied flycatcher (Ficedula hypoleuca) and collared flycatcher (F. albicollis) co-occur on the Swedish island of Öland, where they compete over similar resources. The majority of male pied flycatchers have been found to incorporate elements of the collared flycatcher song in their repertoire. Given that birdsong is partly inherited and partly learned, the relative contribution of genetic predispositions versus acoustic stimuli varies across different species. The results show that in pied flycatchers, song acquisition is tightly correlated with imprinting, and can therefore be greatly influenced by heterospecific tutors in their surroundings, i.e. male collared flycatchers. I found that pied males are capable of not only memorizing collared song elements, but also producing them with high fidelity. Thus, I infer that pied flycatchers are characterized by a high degree of vocal plasticity.

Citizen science, which uses volunteer observers in research, is fast becoming standard practice in ecology. In this thesis, I begin with an essay reviewing the benefits and limitations of citizen science, and then measure the influence of several forms of observer error that might bias ornithological citizen science. Using an internet-based survey, I first found that observer skill level can predict the nature of false-positive detections, where self-identified experts tend to falsely detect more rare species and moderately-skilled observers tend to falsely detect more common species. I also found that overconfidence is widespread among all skill levels, and hence that observer confidence is an unreliable indication of data quality. Using existing North American databases, I then found that older observers tend to detect fewer birds than younger observers -- especially if the birds' peak call frequencies exceed 6 kHz -- and that published long-term population trend estimates and high-pitched (>= 6 kHz) peak bird vocalization frequencies are negatively correlated. Taken together, these data suggest that both hearing loss and other sensory changes might be negatively biasing long-term trend estimates. In the next chapter, I measured how observer experience can bias detection data. In solitary observers, I found that detections tend to increase over the first 5 years of service (e.g. learning effects), after which they decline consistently (e.g. observer senescence). Conversely, among survey groups that may be motivated to exceed a previous year's species count, I found that species richness tends to increase consistently with consecutive survey years. In this case, individual sensory deficits may be offset by group participation. Lastly, I re-evaluated the established assumption that the quality of new volunteers on North American Breeding Bird Survey routes is increasing over time. I showed that the existing measure of “quality” ignores variable lengths of observer service, and that, after accounting for this variable, “quality” is unchanging. Throughout this thesis, I also show how generalized additive mixed models can address these biases statistically. My findings offer new opportunities to improve the accuracy and relevance of citizen science, and by extension, the effectiveness of wildlife conservation and management.