Geographic variation in the whistle vocalisations of dolphins has previously been reported. However, most studies have focused on the whole whistle repertoire, with little attempt to classify sounds into biologically relevant categories. Common bottlenose dolphins (Tursiops truncatus) use individually distinctive signature whistles which are thought to help maintain contact between conspecifics at sea. These whistles may show a different kind of variation between populations than non-signature whistles. Here I investigate signature whistle use and variation in the two recognised species of bottlenose dolphins (T. truncatus and T. aduncus) from populations inhabiting the coastal waters of the North America, Scotland, South Africa, Tanzania, Japan, Australia and New Zealand, and one captive colony. I identified likely signature whistles (signature whistles types, SWTs) from acoustic recordings by combining two novel techniques: automated contour categorisation in ARTwarp (Deecke and Janik, 2006) and a specific bout analysis based on the timing of signature whistle production in T. truncatus termed SIGID (Janik et al. in press). Three ways of categorising the contours were tested and between 87 and 111 SWTs were identified in total. Repeated emissions of stereotyped contours were apparent in the repertoire of all T. aduncus populations using both automated and human observer categorisation, providing good evidence for signature whistle use in this species. There was significant inter-specific variation in the frequency parameters, looping patterns and duration of SWTs. Inflection points, duration and measures of SWT complexity showed high variation within populations, suggesting inter- and intra-individual modification of these parameters, perhaps to enhance identity encoding or convey motivational information. Using 328 bases of the mtDNA control region, I found high levels of population differentiation (FST and φST) within the genus Tursiops. These data do not support a link between mtDNA population differentiation and variability in call type. Instead, morphological variations at the species level, and learned differences at the population level, better explain the variation found.

Variation in advertisement call structure of whistling frogs, Litoria ewingi, was studied among breeding sites in the vicinity of Christchurch on the East coast and Harihari on the West coast of the South Island. Males vocalized in breeding choruses throughout the year and females moved toward and appeared to evaluate calls of territorial males before initiating amplexus. Acoustic interactions between neighbours led to modification of call structure and timing, and wrestling matches between males were frequent. I quantified call structure for 1623 calls of 168 individuals using 24 call parameters. Most temporal characteristics were significantly correlated with the caller's body temperature and dominant frequency was negatively correlated with body size. These results are consistent with the prediction of temperature-dependent metabolic rates in a poikilotherm's nervous system. I compared call structure among the study populations using both multivariate and univariate analyses. Advertisement call structure showed highly significant variation among populations for most call variables. The greatest difference occurred between the West and East coast populations, and a clinal trend occurred in the East coast populations on a microgeographic scale. Variation among East coast populations in some variables was comparable to the scale of variation between coasts. These results suggest that whistling frogs exhibit natal philopatry. I obtained repeated recordings for 21 individuals and examined variation in call structure within and among individuals using nested multivariate analyses of variance. Highly significant variation occurred both within and among individuals for most call characters, but certain call characters were more variable among individuals. This suggests that whistling frog advertisement calls are individually distinctive.

An investigation was conducted to determine if laryngeal valving economy, as reflected in measures of laryngeal airway resistance during vowel production, varies across adulthood. Toward this end, sixty healthy men were studied, ten from each of six age groups--25, 35, 45, 55, 65, and 75 years (± 2 years). Results showed that there are age-related differences in laryngeal airway resistance during vowel production, and that these differences are characterized by a lower mean resistance in 75-year-old men than in younger men of the ages studied. This finding provides insight into mechanisms regarding the impact of age on laryngeal function and has important clinical implications for the evaluation and management of men with voice disorders.

Climate change has been predicted to have long-term consequences for North American ecosystems. Amphibians in particular are considered indicators of ecosystem health because of their sensitivity to environmental change – due in part to their semi-permeable skin and aquatic developmental requirements. Amphibians have been experiencing population declines on a global scale, suggested in part to be due to changes in reproductive behaviour and timing. My thesis examines the abiotic correlates of timing of calling in southeastern Ontario anurans, as well as the extent to which the timing of calling events vary within and among species. I focused on eight species of frogs using both a 40-year historical dataset and a 5-year field-collected dataset of environmental variation and anuran activity. From analysis of the historical dataset, Lithobates pipiens was the only species out of eight to emerge significantly earlier, by an estimated 22 days over four decades. Both L. pipiens and Anaraxyus americanus have advanced initiation of calling over a four-decade span significantly earlier by an estimated 37.2 and 19.2 days, respectively, correlating with significant regional increases in spring air temperatures (2.8°C over four decades). Global frog declines or range shifts relate ultimately to changes in reproductive behaviour and timing mediated by shifting climate. From my analysis of the field-collected dataset, I concluded that species varied in the environmental predictors that best predicted this variation may be a consequence of varying reproductive strategies between early spring “explosive” breeders versus late prolonged breeders. There was also significant among-location variation in calling activity for four prolonged breeding species, which may be an effect of significant microclimatic variation between locations surveyed. My study suggests that local temperature increases have affected the timing of emergence and the onset of calling activity in some frogs and that microclimatic differences among breeding habitats may be influencing the timing of breeding in some prolonged breeding species. My research aids future conservation and management strategies for North America’s dwindling amphibian populations by quantifying how abiotic factors influence breeding behaviour on both a fine and extended temporal scale as well as by developing and testing standardized methods for long-term species monitoring. / Thesis (Master, Biology) -- Queen's University, 2012-11-12 23:05:34.12

Fragile X syndrome (FXS) is a neurogenetic syndrome characterized by cognitive impairments and high rates of autism spectrum disorder (ASD). FXS is often used as a model for exploring mechanisms and pathways of symptom expression in ASD due to the high prevalence of ASD in this population and the known single-gene cause for ASD in FXS. Early vocalization features – including volubility, canonical complexity, vocalization duration and vocalization pitch – have shown promise in detecting ASD in idiopathic ASD populations but have yet to be extensively studied in a population with a known cause for ASD, such as FXS. The present study characterizes early vocalization features in FXS, demonstrating how these features are associated with language ability and ASD outcomes, as well as highlighting how these features in FXS may diverge from patterns observed in typically developing (TD) populations. We coded vocalization features during a standardized child-examiner interaction in 39 nine-month-old infants (22 FXS, 17 TD) who were then followed up at 24 months to determine developmental and clinical outcomes. Although many findings did not reach statistical significance in this small sample, our results provide preliminary evidence that infants with FXS may demonstrate patterns of associations with 24-month language outcomes that diverge from those observed in typical development, and that certain vocalization features may be associated with later ASD outcomes in the FXS group. These findings warrant more research exploring these features as potential early markers of ASD in FXS. Characterizing the associations of early vocalization features with ASD outcomes in FXS can inform mechanisms of ASD development that can then be tested broadly with other etiologically-distinct populations at risk for ASD. Thus, further characterization of these early vocalization features in typical and atypical development may lead to improved early identification methods, treatment approaches, and overall well-being of individuals in the ASD population.

Vocal communication is central to the coordination of social behavior in many vertebrate species, and it has been particularly well studied in songbirds, which use their songs in different contexts to convey information about the singer or its environment (Catchpole and Slater 2008; Alger et al. 2016). While it is widely accepted that the songs of oscine passerine birds (the songbirds) have two main social functions: intrasexual competition, and courtship (Catchpole and Slater 2008), the evolution of large and complex song repertoires remains an evolutionary puzzle (Byers and Kroodsma 2009). The question is: why do some songbird species produce an elaborate vocal repertoire, while other species carry out courtship and competition with a far smaller and simpler repertoire? In this thesis I examine the adaptive value (social function) of song in malemale competition with an eye toward understanding how intrasexual selection may have driven the elaboration of the male Bachman’s sparrow (Peucea aestivalis) vocal repertoire. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2019. / FAU Electronic Theses and Dissertations Collection

North American red squirrels are a solitary, territorial species that confront various predators. Previous research proposed that squirrels produce predator-specific, referential ‘seet’ and ‘bark’ alarm calls to aerial and ground predators, respectively. To test this hypothesis, I examined alarm call production during natural encounters with predators, conspecific intruders and in a series of predator simulation experiments. Call production patterns were consistent across all types of disturbance and involved protracted bouts where both call types were inter-mixed. Hence, the call types were not predator-specific but rather their patterning reflected the persistence of disturbances of any type. Tests of alternative call functions further indicated that calls were not actually directed at conspecifics, but rather at predators and intruders and might function to deter or repel them directly. These outcomes are consistent with life-history details of red squirrels and contradict the proposal that this species produces predator-specific, referential alarm calls. / xi, 153 leaves : ill. ; 29 cm

Vocalization behavior of captive loggerhead shrikes was studied at the Avian Science and Conservation Centre of McGill University. In the first stage, calls of two pairs kept in indoor cages were individually recorded not only to catalogue these calls spectrographically and quantitatively but also to use them in identifying the birds sexually. Males vocalized 21 call figures for 16.50% of the observation time and females, 8 call figures for 2.64% of the observation time. Males contiguously delivered 1 to 11 bouts with a mean of 7.25 min for a rate of 6.06 bouts/h; females delivered 1 to 9 bouts with a mean of 4.07 min for a rate of 1.27 bouts/h. Males not only vocalized at a higher rate and longer than females, but also demonstrated trill calls which the females did not do. In the second stage, five pairs were paired in large outdoor breeding pens. Their calls were recorded and current visual displays observed in an effort to understand calls related to breeding behaviors. Two new calls figures vocalized by males as well as 2 call figures by young shrikes were recorded. Each male demonstrated distinctive calls that differed from those of other males during nest-site selection, nest building and copulation, but similar calls during food offering, aggressive and alarm behavior. Despite the call differences, all males performed similar visual displays during the above activities. Conversely, breeding females gave no calls, other than harsh calls during food offering, food begging, aggressive and alarm behaviors.

The behaviours of eastern chipmunks (Tamias striatus) in response to aerial predators were studied in the field using trained kestrels (Falco sparverius) flying over a food patch where animals of known gender, age and burrow location categories were foraging. Their typical response was to flee toward a nearby refuge while producing a trill. After a few seconds, chipmunks usually emerged and started to produce long (but sometimes interrupted) series of chucks while facing the predator. Acoustical analysis showed that the trill consisted of a rapid series of usually high pitched and variable notes while most chucks consisted of two partially overlapping components differing mainly in frequency range. No differences were observed between individuals of different categories for most antipredator responses. Various observations suggest that the trill functions to startle the predator and that the chuck deters the predator from hunting in the area.

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