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Avian vocalizations have evolved in response to a variety of abiotic and biotic selective pressures. While there is some support for signal convergence in similar habitats that are attributed to adaptation to the acoustic properties of the environment (the "acoustic adaptation hypothesis," AAH), there is also evidence for character displacement as a result of competition for signal space among coexisting species (the "acoustic niche partitioning hypothesis"). We explored the acoustic space of avian assemblages distributed along six different habitat types (from herbaceous habitats to warm rainforests) in southeastern Queensland, Australia. We employed three acoustic diversity indices (acoustic richness, evenness, and divergence) to characterize the signal space. In addition, we quantified the phylogenetic and morphological structure (in terms of both body mass and beak size) of each community. Acoustic parameters showed a moderately low phylogenetic signal, indicating labile evolution. Although we did not find meaningful differences in acoustic diversity indices among habitat categories, there was a significant relationship between the regularity component (evenness) and vegetation height, indicating that acoustic signals are more evenly distributed in dense habitats. After accounting for differences in species richness, the volume of acoustic space (i.e. acoustic richness) decreased as the level of phylogenetic and morphological resemblance among species in a given community increased. Additionally, we found a significantly negative relationship between acoustic divergence and divergence in body mass indicating that the less different species are in their body mass, the more different their songs are likely to be. This implies the existence of acoustic niche partitioning at a community level. Overall, while we found mixed support for the AAH, our results suggest that community-level effects may play a role in structuring acoustic signals within avian communities in this region. This study shows that signal diversity estimated by diversity metrics of community ecology based on basic acoustic parameters can provide additional insight into the structure of animal vocalizations. [ABSTRACT FROM AUTHOR]

Purpose: Children with hearing loss (HL), including those with hearing aids (HAs) and cochlear implants (CIs), often have difficulties contrasting words like "beach" versus "peach" and "dog" versus "dock" due to challenges producing systematic voicing contrasts. Even when acoustic contrasts are present, these may not be perceived as such by others. This can cause miscommunication, leading to poor self-esteem and social isolation. Acoustic evidence is therefore needed to determine if these children have established distinct voicing categories before entering school and if misperceptions are due to a lack of phonological representations or due to a stillmaturing implementation system. The findings should help inform more effective early intervention. Method: Participants included 14 children with HL (eight HA users, five CI users, and one bimodal) and 20 with normal hearing, all English-speaking preschoolers. In an elicited imitation task, they produced consonant-vowel-consonant minimal pair words that contrasted voicing in word-initial (onset) or word-final (coda) position at all three places of articulation (PoAs). Results: Overall, children with HL showed acoustically distinct voicing categories for both onsets and codas at all three PoAs. Contrasts were less systematic for codas than for onsets, as also confirmed by adults' perceptual ratings. Conclusions: Preschoolers with HL produce acoustic differences for voiced versus voiceless onsets and codas, indicating distinct phonological representations for both. Nonetheless, codas were less accurately perceived by adult raters, especially when produced by CI users. This suggests a protracted development of the phonetic implementation of codas, where CI users, in particular, may benefit from targeted intervention. [ABSTRACT FROM AUTHOR]

Animal vocalisations can signify diverse behavioural contexts, knowledge of which can be applied in bioacoustic monitoring programs. Australia's endemic black cockatoos (Calyptorhynchus sp., family Cacatuidae) are highly vocal species that are threatened in many locations. In this study, we describe the nest‐associated vocal behaviours of two endangered subspecies of black cockatoo, the south‐eastern red‐tailed black cockatoo, C. banksii graptogyne and the Kangaroo Island glossy black cockatoo, C. lathami halmaturinus. Breeding success is limiting their recoveries and nest monitoring is challenging, but vocal recordings might provide valuable long‐term information hard to obtain otherwise. We recorded daily vocal activity at wild nests of both cockatoos using autonomous sound recorders. Combined with behavioural observations and video footage, we identified vocalisations characteristic of six behavioural contexts at nests: birds in flight, while perched, during begging (adult females), during courtship displays (adult males), when entering or sitting near to the nest hollow entrance (adult females), and from nestlings. Linear discriminant analysis on 12 acoustic measurements correctly classified 58.4% of calls of the red‐tailed black cockatoo (n = 907 calls from eight nests) and 62.9% of calls of the glossy black cockatoo (n = 1632 calls from 11 nests). In both subspecies, the female nest call and nestling calls are the most conspicuous vocal indicators of active nesting, and therefore should be considered for their bioacoustic potential. Other adult vocalisations indicate a range of behavioural contexts that could be informative for monitoring nesting behaviour, and its association to habitat features, in these endangered subspecies. [ABSTRACT FROM AUTHOR]

Establishing appropriate conservation management objectives and actions for seabirds requires timely detection of changes in their populations. However, obtaining regular accurate measures of seabird population size and trends can be difficult due to logistical and financial constraints in accessing remote breeding sites. The Short-tailed Shearwater (Ardenna tenuirostris) is a wide-ranging, burrow-nesting Procellariiform with an estimated breeding population size of ca 23 million individuals. Despite its ecological significance, there is currently limited monitoring of the species. In the present study, eight acoustic data loggers were deployed across six sites over two breeding seasons to assess the efficacy of acoustic monitoring. Five acoustic indices were used to investigate vocal activity over the breeding season, detect phenology events, and to determine the most accurate period to assess the density of occupied nests. The general pattern over the breeding season was similar for several of the acoustic indices and reflected colony attendance patterns. Linear regressions fitted to the normalised difference soundscape index values and density of occupied nests (burrows·m−2) revealed significant relationships in both the incubation and chick-rearing. The results suggest that passive acoustic monitoring could be used as an effective method to predict nesting density in Short-tailed Shearwater breeding colonies. Used in conjunction with information on the breeding colony area, this could enable regular estimates of colony population size. Such information is crucial for the early detection of population trajectory changes. The method may also be applicable for other burrow- or surface-nesting seabirds for which regular wide-spread monitoring currently proves difficult. [ABSTRACT FROM AUTHOR]

This dataset represents expert-validated occurrence records of calling frogs across Australia collected via the national citizen science project FrogID (http://www.frogid.net.au). FrogID relies on participants recording calling frogs using smartphone technology, after which point the frogs are identified by expert validators, resulting in a database of georeferenced frog species records. This dataset represents one full year of the project (10 November 2017-9 November 2018), including 54,864 records of 172 species, 71% of the known frog species in Australia. This is the first instalment of the dataset, and we anticipate providing updated datasets on an annual basis. [ABSTRACT FROM AUTHOR]

Paleo-climatic fluctuations have driven episodic changes in species distributions, providing opportunities for populations to diverge in isolation and hybridise following secondary contact. Studies of phylogeographic diversity and patterns of gene flow across hybrid zones can provide insight into contemporary species boundaries and help to inform taxonomic and conservation inferences. Here we explore geographic diversity within the acoustically divergent yet morphologically conserved south-eastern Australian smooth frog complex and assess gene flow across a narrow hybrid zone using mitochondrial nucleotide sequences and nuclear genome-wide single nucleotide polymorphisms. Our analyses reveal the presence of an evolutionarily distinct taxon restricted to the Otway Plains and Ranges, Victoria, which forms a narrow (9-30 km wide), spatiotemporally stable (>50 years) hybrid zone with Geocrinia laevis, which we describe herein as a new species., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Crown Copyright © 2023. Published by Elsevier Inc. All rights reserved.)

Many studies have compared results from sound recordings and traditional point-count survey observer data when surveying avian communities. None have investigated the use of a moving sound recorder to replicate line-transect surveying. We conducted point-count surveys and line-transect surveys in four urban/peri-urban habitats in Darwin, tropical Australia, with stationary and moving sound recorders, respectively, to assess whether such a combination would result in more bird species being identified than with either technique alone. More bird species were identified using sound recordings than standard observer data. Further, the difference in the number of species identified between the observer and audio from point-count surveys was found to be significant with audio identification being more accurate; however, line-transect surveys showed no significant difference between the two identification methods. Overall, there was no statistical significance between using point-count surveys and line-transect surveys for total species identified. Linear mixed modelling found the interaction between habitat and survey type (point-count vs line-transect) was strongly significant, but not so that between habitat and survey method (sound recording vs human observation). Our results indicate that the integration of bioacoustic and drone technologies with traditional avian surveying techniques adds significant additional identifications when compiling a species list of an area. • The use of bioacoustic technology is advantageous when conducting avian surveys; • Drones can be a valuable tool when conducting avian surveys in challenging climatic conditions; • Bioacoustic and drone technology can be effectively combined to gather avian species data. [ABSTRACT FROM AUTHOR]

Anthropogenic habitat modification significantly challenges biodiversity. With its intensification, understanding species' capacity to adapt is critical for conservation planning. However, little is known about whether and how different species are responding, particularly among frogs. We used a continental-scale citizen science dataset of >226,000 audio recordings of 42 Australian frog species to investigate how calling-a proxy for breeding-phenology varied along an anthropogenic modification gradient. Calling started earlier and breeding seasons lengthened with increasing modification intensity. Breeding seasons averaged 22.9 ± 8.25 days (standard error) longer in the most modified compared to the least modified regions, suggesting that frog breeding activity was sensitive to habitat modification. We also examined whether calls varied along a modification gradient by analysing the temporal and spectral properties of advertisement calls from a subset of 441 audio recordings of three broadly distributed frog species. There was no appreciable effect of anthropogenic habitat modification on any of the measured call variables, although there was high variability. With continued habitat modification, species may shift towards earlier and longer breeding seasons, with largely unknown ecological consequences in terms of proximate and ultimate fitness., (© 2022 The Authors. Global Change Biology published by John Wiley & Sons Ltd.)

• Logging and wildfire are major disturbance factors in Mountain Ash forests. • Passive acoustic surveys are effective for detecting Yellow-bellied Gliders. • Site occupancy by Yellow-bellied Gliders was correlated to undisturbed forest area. • Maintaining mature forest refuges will be critical for Yellow-bellied Gliders. Habitat loss and degradation are two of the greatest threats to biodiversity conservation globally. In Australia, the incidence of wildfire and native forest logging contribute substantially to these processes and have been linked to reduced species diversity and abundance. Arboreal species such as the Yellow-bellied Glider (Petaurus australis), are thought to be susceptible to these disturbances due to their reliance on large patches of forest and hollow-bearing trees. We aimed to assess the impact of logging and wildfire on site occupancy by the Yellow-bellied Glider in Mountain Ash forests of the Central Highlands of Victoria. We deployed autonomous recording units for 14 nights at 70 sites and searched recordings for Yellow-bellied Glider vocalisations. Yellow-bellied Gliders were detected at 30% (N = 21) of sites. Site occupancy increased with an increasing proportion of the landscape (within 400 m of the recorder) that had not been logged within the last 100 years or burnt by wildfire within the last 10 years. Habitat disturbance caused by logging and fire therefore limit the site occupancy of Yellow-bellied Gliders and likely impact its conservation status. It is therefore critical that appropriate management of timber resources protects large patches of old-growth forest providing food resources and hollows, and the connectivity between large forest patches. [ABSTRACT FROM AUTHOR]

Abstract: A new hybrid method for automated frog sound identification, using spectral centroid, Shannon entropy and Rényi entropy is proposed. The advantage of using entropy based information theoretic approach for analyzing complexity of bioacoustics signals in animal vocalization is discussed. Sound samples from nine species of Microhylidae frogs are first segmented into syllables. Fourier spectral centroid, Shannon entropy and Rényi entropy of the syllables are then determined. Finally, nonparametric k-th nearest neighbour (k-NN) classifier is used to recognize the frog species based on these three extracted features. Result shows that the k-NN classifier based on these selected features is capable to identify the species of the frogs with an average accuracy of 98%. It is found that the accuracy reduces significantly only when the noise levels higher than −20dB. [Copyright &y& Elsevier]

• Automated species identification is the key goal for acoustic studies of wildlife. • Chorusing species present a challenge for automated detection. • Acoustic indices used as predictive features to detect chorusing frog species. Acoustic monitoring provides opportunities for scaling up bioacoustic study of vocal animals to greater temporal and spatial scales. However, the large amounts of audio that can be easily and efficiently collected necessitates automated methods of analysis to extract useful ecological data. Acoustic indices have been used in spectrographic visualisation of long environmental recordings to successfully identify many biological sounds from their acoustic patterns and features. In particular, the choruses of several frog species are conspicuous in these spectrogram images which suggests that acoustic indices may be useful for detecting species in automated sound classification algorithms. The aim of this study was to investigate the use of acoustic indices as predictors in classification models for automated identification of frog species in environmental sound recordings from breeding habitats in north Queensland, Australia. Three types of classification models (random forests, support vector machines and gradient boosting) were trained and validated on a data set of 3274 1-minute audio segments labelled for the presence or absence of calling of 12 target frog species, and a feature set of 11 acoustic indices calculated on frequency bins of bandwidth 43.1 Hz. Classification performance was high for all 12 target species on the validation data set held out from the labelled training data (precision range 0.90–1.00 and recall range 0.83–0.99). However, performance declined for most target species when predicting frog calling on a further test data set taken from unseen recordings from the same sites. Best prediction results on the test data were achieved for species with the most training data, indicating accuracy may be improved by increasing training data, and this method is best suited to predicting chorusing of common species. [ABSTRACT FROM AUTHOR]