Australian Birds Research Articles

Long- and short-term responses to climate change in body and appendage size of diverse Australian birds.

Changes to body size and shape have been identified as potential adaptive responses to climate change, but the pervasiveness of these responses has been questioned. To address this, we measured body and appendage size from 5013 museum bird skins of 78 ecologically and evolutionary diverse Australian species. We found that morphological change is a shared response to climate change across birds. Birds increased relative bill surface area, tarsus length, and relative wing length through time, consistent with expectations of increasing appendage size as climates warm. Furthermore, birds decreased in absolute wing length, consistent with the expectation of decreasing body size in warmer climates. Interestingly, these trends were generally consistent across different diets and migratory and thermoregulatory behaviors. Shorter term responses to higher temperatures were contrary to long-term effects for appendages, wherein relative appendage size decreased after hotter years, indicating the complex selective pressures acting on birds as temperatures rise with climate change. Overall, our findings support the notion that morphological adaptation is a widespread response to climate change in birds that is independent of other ecological traits.

First peoples’ names for Australian birds? Only with free, prior and informed consent

First peoples’ names for Australian birds? Only with free, prior and informed consent

Measuring avian bill size: comparing and evaluating 3D surface scanning with traditional size estimates in Australian birds

Unidimensional measurements for estimating bill size, like length and width, are commonly used in ecology and evolution, but can be criticised due to issues with repeatability and accuracy. Furthermore, formula‐based estimates of bill surface area tend to assume uniform bill shapes across species, which is rarely the case. 3D surface scanning can potentially help overcome some such issues by collecting detailed external morphology and direct measurements of surface area, rather than composite estimates of size. Here, we evaluate the use of 3D surface scanners on avian museum specimens to test the repeatability of 3D‐based measurements and compare these to traditional formula‐based methods of estimating bill size from unidimensional measurements. Using 28 Australian bird species, we investigate inter‐observer repeatability of surface area measurements from 3D surface scans. We then compare 3D‐based size estimates to formula‐based size estimates to infer the accuracy and precision of formula‐based measurements of bill surface area. We find that morphometric measurements from 3D surface scans are highly repeatable between observers, without the need for extensive training, demonstrating an advantage over unidimensional measuring methods, like callipers. When comparing 3D‐based measurements to formula‐based estimates of bill surface area, most formulae for estimating size consistently underestimate surface area, and with considerable variation between species. Where 3D scanning is not possible, we find that a commonly used cone formula for estimating bill size is most precise across diverse bill shapes, therefore supporting its use in interspecific contexts. However, we find that incorporating an additional unidimensional measure of bill curvature into formulae improves the accuracy of the calculated area. Our results reveal the high potential for 3D surface scanners in avian morphometric research, especially for studies necessitating large sample sizes collected by multiple observers, and gives suggestions for formula‐based approaches to estimate bill size.

Which birds have the most to lose? an analysis of bird species’ feeding habitat in changing Australian landscapes

Australia has lost vast areas of its natural vegetation through agriculture and urbanization, resulting in the area of suitable habitat for many Australian bird species being greatly diminished. Given the geographical and ecological biases in anthropogenic land use, the impact of habitat loss now and into the future may be disproportionately high for some species, threatening their long-term persistence. Such changes are occurring rapidly, and habitat loss needs to be monitored dynamically to prevent extinction. To monitor changes in available unmodified species habitat, we use species’ area of feeding habitat (AFH), which represents the area of habitat within a species’ range with vegetation matching their feeding requirements. We analysed the past, current and future threats of habitat modification for 467 Australian bird species by calculating AFH across three time periods: pre-colonization, current (2020), and a projected future scenario (2100). These values were used to identify species subject to substantial habitat loss due to urbanization and agriculture and delineate predictors of such losses. Most species had experienced habitat loss since colonization (n = 442, 95%), and species that had already experienced considerable habitat loss were more likely to lose habitat into the future. Species with particular habitat associations (e.g., Mallee), were also more prone to greater proportions of habitat lost. The results highlight the utility of AFH and emphasize the importance of protecting what habitat remains for the species with highly depleted geographic ranges, noting that those that have experienced the most loss of unmodified habitat are the most likely to lose more unmodified habitat under future conditions.

Foraging ecology of eucalypt forest and woodland birds in the Great Western Woodland I: Small insectivores

ABSTRACT Australian warblers (Acanthizidae) and pardalotes (Pardalotidae) are abundant keystone species in Australia. Collectively they help regulate arthropod populations and dampen outbreaks of phytophagous insects. Their conservation in the face of habitat degradation and climate change is essential for the retention of healthy forest ecosystems and biodiversity. Information at the level of detail required for effective conservation management is missing for most Australian birds, including warblers and pardalotes. It is unlikely the data needed for the conservation of these species will be obtained in time to prevent further losses of avian biodiversity. However, it is important to try. This paper describes the foraging behaviour during spring of seven species of Australian warblers and pardalotes (small insectivores) in the Great Western Woodland, Western Australia and expands our knowledge of the ecology of these birds. As reported for small insectivores elsewhere in the world, species differed in prey-attack behaviours, foraging substrates, plant species used for foraging, foraging heights, and habitats. These data are used to explain why, without changes in how Australia approaches the preservation of biodiversity, abundant birds, such as Australian warblers and pardalotes will decline towards extinction.

Genomic and transcriptomic resources for the brown thornbill (Acanthiza pusilla) to support the conservation of a critically endangered subspecies

Abstract* The brown thornbill (Acanthiza pusilla) is a songbird endemic to eastern Australia with five recognised subspecies within the brown thornbill. The most notable is the King Island brown thornbill (Acanthiza pusilla magnirostris) of which there are less than 100 remaining and based on expert elicitation are the most likely Australian bird to become extinct in the next 20 years. We sequenced PacBio HiFi reads of the brown thornbill to generate a high-quality reference genome 1.25Gb in size and contig N50 of 20.1Mb. Additionally, we sequenced mRNA from three tissues to generate a global transcriptome to aid with genome annotation. The generation of a reference genome for the brown thornbill provides an important resource to align additional genomic data which will be produced in the near future.

Opportunistic sampling of yellow canary (Crithagra flaviventris) has revealed a high genetic diversity of detected parvoviral sequences.

Parvoviruses are known to be significant viral pathogens that infect a wide range of species globally. However, little is known about the parvoviruses circulating in Australian birds, including yellow canaries. Here, we present four parvoviral sequences including three novel parvoviruses detected from 10 yellow canaries (Crithagra flaviventris), named canary chaphamaparvovirus 1 and -2 (CaChPV1 and CaChPV2), canary dependoparvovirus 1 and -2 (CaDePV1 and CaDePV2). The whole genome sequences of CaChPV1, CaChPV2, CaDePV1, and CaDePV2 showed the highest identity with other parvoviruses at 76.4%, 75.9%, 84.0%, and 59.1%, respectively. Phylogenetic analysis demonstrated that CaChPV1 and CaChPV2 were clustered within the genus Chaphamaparvovirus. Meanwhile, CaDePV1 and CaDePV2 fall within the genus Dependoparvovirus and have the closest evolutionary relationship to the bird-associated dependoparvoviruses. Overall, this study enriched our understanding of the genetic diversity among avian parvoviruses within the Parvoviridae family.

The influence of plant scents on nest box inspection by Eastern Rosella (Platycercus eximius)

ABSTRACT Many cavity nesters add volatile plants with medicinal properties to their nests. In Australia, eucalyptus and tea-trees are highly volatile plants, which have antiparasitic and antimicrobial properties. Here, we tested whether scents of eucalypt (Eucalyptus polybractea) and tea tree (Melaleuca alternifolia) essential oils can attract birds to newly installed nest boxes. Twenty-four nest boxes received three scent treatments (eucalypt, tea tree, control) for 10 days each using a Latin-square design. Bird visitation was recorded using camera traps. Eastern Rosellas (Platycercus eximius) visited the nest boxes the most (1,454 visits) and were therefore the focus of the study. Eastern Rosellas did not change their behaviours in response to the eucalypt scent in nest boxes: there was no difference in visitation, duration of visits or nest box inspection behaviour between nest boxes with eucalypt scent and those with the control scent. However, Eastern Rosellas visited nest boxes with tea tree scent less frequently and spent less time at these boxes than those with the control scent. The mean time that Eastern Rosellas spent inspecting boxes slightly increased over the 10-day period following scent placement at boxes with control and eucalypt scents, while it sharply decreased at boxes with tea tree scent. This is the first study demonstrating that an Australian bird detected and behaved differently in response to plant volatiles. The use of scents may offer opportunities to not only attract, but potentially also deter certain birds from using particular hollows.

Assessing adequacy of citizen science datasets for biodiversity monitoring.

Tracking the state of biodiversity over time is critical to successful conservation, but conventional monitoring schemes tend to be insufficient to adequately quantify how species' abundances and distributions are changing. One solution to this issue is to leverage data generated by citizen scientists, who collect vast quantities of data at temporal and spatial scales that cannot be matched by most traditional monitoring methods. However, the quality of citizen science data can vary greatly. In this paper, we develop three metrics (inventory completeness, range completeness, spatial bias) to assess the adequacy of spatial observation data. We explore the adequacy of citizen science data at the species level for Australia's terrestrial native birds and then model these metrics against a suite of seven species traits (threat status, taxonomic uniqueness, body mass, average count, range size, species density, and human population density) to identify predictors of data adequacy. We find that citizen science data adequacy for Australian birds is increasing across two of our metrics (inventory completeness and range completeness), but not spatial bias, which has worsened over time. Relationships between the three metrics and seven traits we modelled were variable, with only two traits having consistently significant relationships across the three metrics. Our results suggest that although citizen science data adequacy has generally increased over time, there are still gaps in the spatial adequacy of citizen science for monitoring many Australian birds. Despite these gaps, citizen science can play an important role in biodiversity monitoring by providing valuable baseline data that may be supplemented by information collected through other methods. We believe the metrics presented here constitute an easily applied approach to assessing the utility of citizen science datasets for biodiversity analyses, allowing researchers to identify and prioritise regions or species with lower data adequacy that will benefit most from targeted monitoring efforts.

Extinct Australian birds: numbers, characteristics, lessons and prospects

ABSTRACT Since European colonisation of Australia in 1788, nine Australian bird species (1.2% of the Australian total) have become extinct, along with 22 subspecies (of 16 species). Consistent with global patterns, Australia’s island endemic birds have been particularly susceptible, comprising eight of the nine species’ extinctions (38% of the bird species endemic to islands smaller than Tasmania), and 13 of the 22 subspecies’ extinctions. The extinction of only one bird species (Paradise Parrot Psephotellus pulcherrimus) from the Australian mainland contrasts with the far higher rate of extinctions of Australian mammals (27 of 312 species that occurred on the Australian mainland), and is comparable with the rate of extinctions of birds on the mainland of other continents over this period. Extinctions of Australian birds were caused mainly by introduced predators (especially for island taxa), habitat degradation, and hunting (for some island taxa). The timing of some extinctions is uncertain, but the first bird extinction subsequent to European colonisation was the loss of the flightless White Gallinule Porphyrio albus from Lord Howe Island over the period 1788–1790. Extinctions have occurred in most decades since then, with the most recent being for Norfolk Island’s White-chested White-eye Zosterops albogularis in the decade 2000–2009. Environmental legislation, an extensive conservation reserve system, and dedicated conservation management efforts have prevented some extinctions. However, local extirpations continue, many threatened species continue to decline and, without an increase in conservation efforts, the rate of extinctions is likely to increase, mainly due to the direct and compounding impacts of climate change.

Biological characteristics of Australian threatened birds

ABSTRACT Over 750 native bird species reside in or regularly migrate to Australia, many of which have experienced rapid changes in habitat extent over the past two centuries. By 2020, eight taxa were considered Extinct and 10% threatened with extinction. Understanding the underlying extrinsic and intrinsic factors that increase extinction risk can allow prioritisation of conservation management and research. Here, we use state-of-the-art phylogenetic comparative models to reveal the most important biological traits that predispose Australian bird species to elevated extinction risk. We use an extensive database of their biological traits and relate these to each species’ national and global IUCN extinction risk status as assessed over the past three decades (in 1990, 2000, 2010, and 2020). We show that high evolutionary distinctiveness (uniqueness), island endemism, and an inability to take advantage of agricultural habitats were the most important traits explaining elevated extinction risk in species when phylogeny is controlled for, suggesting that extinction risk is disproportionately high in species with high evolutionary distinctiveness. Extinct taxa were characterised by large body mass and island endemism compared to taxa extant in 2020. Our study provides the largest and most up-to-date analysis of the intrinsic traits of Australian birds in relation to their extinction risk, and can be used as a baseline in future studies, for prioritisation of conservation actions, and for policy advice on a broad scale.

Trends and patterns in the extinction risk of Australia’s birds over three decades

ABSTRACT Australia recently committed through the Kunming-Montreal Global Biodiversity Framework (GBF) to halt human-induced extinction of known threatened species and to reduce extinction risk of threatened species significantly by 2030. We review recent trends in extinction risk of Australian birds to provide context for current and future conservation efforts. We calculate the Red List Index (RLI) for all Australian birds as well as subsets based on geography, habitat and taxonomy. Over the period 2010 to 2020, the number of taxa reassigned to lower categories of extinction risk (n = 20; 1.5% of all taxa included) was greatly outweighed by the number moved to higher categories owing to deteriorating status (n = 93; 7%). This resulted in the steepest decadal decline in the RLI since data were first compiled in 1990. It was chiefly driven by rapid population declines in migratory shorebirds, loss of suitable habitat for species affected by wildfire in 2019–2020 and, to a lesser extent, declines in the abundance of upland rainforest birds. To a small extent, these losses were counterbalanced by improvements in status of some bird species resulting from local eradication of invasive mammals, primarily from Macquarie Island. For Australia to meet the commitments recently adopted through the GBF, conservation interventions (and hence funding) will need to be scaled up substantially. The RLI is well placed for monitoring progress towards the GBF targets and for communicating trends in the extinction risk to national avifaunas.

The cestode genus Gastrotaenia Wolffhügel, 1938 (Platyhelminthes: Cyclophyllidea) in Australian waterfowl (Aves: Anatidae)

ABSTRACT Examination of museum collections revealed the presence of two species of Gastrotaenia Wolffhügel, 1938 (Cestoda: Hymenolepididae) in Australian anatid birds. Gastrotaenia dogieli (Ginetsinskaya, 1944) was found in the gizzard of the following species of Australian ducks from New South Wales: Anas castanea (Eyton), Anas rhynchotis Latham, Anas gracilis Buller, Aythya australis (Eyton), Chenonetta jubata (Latham) and Malacorhynchus membranaceus (Latham). Gastrotaenia cf. paracygni Czapliński & Ryžikov, 1966 was found in the proventriculus of black swans (Cygnus atratus (Latham)) from New South Wales and Victoria. The two species are reported for the first time from Australia. Specimens of Gastrotaenia without scoleces, and therefore not identifiable to species, were present in Anas superciliosa Gmelin and Biziura lobata (Shaw).

The feasibility of implementing management for threatened birds in Australia

ABSTRACT There are many impediments to conserving threatened birds. Some can be overcome through concerted action across multiple species while others require species-specific research and intensive management. We assess the feasibility of managing 202 threats identified in the Action Plan for Australian Birds across 217 Australian threatened bird taxa against five metrics – financial, technical, temporal, political and social. A higher percentage of all threats to all taxa was assessed as having low or very low financial (43%), technical (32%) or temporal (29%) feasibility than political (9%) or social feasibility (7%). The feasibility of managing the most difficult threat to a taxon was low or very low for 52% of the threats identified. Within Australia, the main impediments to addressing most threats are technical and financial, indicating that research and funding should be domestic conservation priorities. Addressing threats linked to habitat destruction/degradation, climate change, invasive species and pollution is limited by the long timescales required to alleviate them, emphasising the urgency of commencing action. Outside Australia, social and political constraints are the main impediments to Australian conservation managers influencing action on habitat loss, species over-exploitation and climate change, but there are also technical, financial and temporal impediments to reducing threats from pollution, invasive species and climate change. Advocacy is therefore also important for addressing threats facing birds outside Australia. Our study provides a platform upon which to build more explicit and efficient management of threatened birds, prioritise efforts in research, funding and advocacy and contribute to reducing losses from Australia’s avifauna.

Using citizen science to identify Australia’s least known birds and inform conservation action

ABSTRACT Citizen science is a popular approach to biodiversity surveying, whereby data that are collected by volunteer naturalists may help analysts to understand the distribution and abundance of wild organisms. In Australia, birdwatchers have contributed to two major citizen science programs, eBird (run by the Cornell Lab of Ornithology) and Birdata (run by Birdlife Australia), which collectively hold more than 42 million records of wild birds from across the country. However, these records are not evenly distributed across space, time, or taxonomy, with particularly significant variation in the number of records of each species in these datasets. In this paper, we explore this variation and seek to determine which Australian bird species are least known as determined by rates of citizen science survey detections. We achieve this by comparing the rates of survey effort and species detection across each Australian bird species’ range, assigning all 581 species to one of the four groups depending on their rates of survey effort and species observation. We classify 56 species into a group considered the most poorly recorded despite extensive survey effort, with Coxen’s Fig Parrot Cyclopsitta coxeni, Letter-winged Kite Elanus scriptus, Night Parrot Pezoporus occidentalis, Buff-breasted Buttonquail Turnix olivii and Red-chested Buttonquail Turnix pyrrhothorax having the very lowest numbers of records. Our analyses provide a framework to identify species that are poorly represented in citizen science datasets. We explore the reasons behind why they may be poorly represented and suggest ways in which targeted approaches may be able to help fill in the gaps.

Draft genomes of novel avian Chlamydia abortus strains from Australian Torresian crows (Corvus orru) shed light on possible reservoir hosts and evolutionary pathways.

Chlamydia abortus, an obligate intracellular bacterium, is a major causative agent of reproductive loss in ruminants, with zoonotic potential. Though this pathogen is primarily known to infect livestock, recent studies have detected and isolated genetically distinct avian strains of C. abortus from wild birds globally. Before this study, only five avian C. abortus genomes were publicly available. Therefore, we performed culture-independent probe-based whole-genome sequencing on clinical swabs positive for avian C. abortus obtained from Australian Torresian crows (Corvus orru) in 2019 and 2020. We successfully obtained draft genomes for three avian C. abortus strains (C1, C2 and C3), each comprising draft chromosomes with lengths of 1 115 667, 1 120 231 and 1 082 115 bp, and associated 7 553 bp plasmids, with a genome completeness exceeding 92 %. Molecular characterization revealed that these three strains comprise a novel sequence type (ST333), whilst phylogenetic analyses placed all three strains in a cluster with other avian C. abortus genomes. Interestingly, these three strains share a distant genomic relation (2693 single nucleotide variants) with the reference strain 15-58d/44 (ST152), isolated from a Eurasian magpie (Pica pica) in Poland, highlighting the need for more publicly available genomes. Broad comparative analyses with other avian C. abortus genomes revealed that the three draft genomes contain conserved Chlamydia genomic features, including genes coding for type III secretion system and polymorphic membrane proteins, and potential virulence factors such as the large chlamydial cytotoxin, warranting further studies. This research provides the first avian C. abortus draft genomes from Australian birds, highlighting Torresian crows as novel reservoir hosts for these potential pathogens, and demonstrates a practical methodology for sequencing novel Chlamydia genomes without relying on traditional cell culture.

Characterisation of a novel aviadenovirus associated with disease in tawny frogmouths (Podargus strigoides)

Aviadenoviruses are widespread in wild birds but rarely cause disease in nature. However, when naïve species are exposed to poultry or aviaries, aviadenoviruses can lead to disease outbreaks. This study characterised a novel aviadenovirus infection in a native Australian bird, the tawny frogmouth (Podargus strigoides) during an outbreak investigation. The identified complete genome of aviadenovirus, named tawny frogmouth aviadenovirus A (TwAviAdV-A) was 41,175 bp in length containing 52 putative genes. TwAviAdV-A exhibits the common aviadenovirus genomic organisation but with a notable monophyletic subclade in the phylogeny. The TwAviAdV-A virus was hepatotrophic and the six frogmouths presented to the wildlife hospitals in South Eastern Queensland most commonly exhibited regurgitation (in four frogmouths). Three were died or euthanized, two recovered, and one showed no signs. The detection of TwAviAdV-A in frogmouths coming into care re-emphasizes the need for strict biosecurity protocols in wildlife hospitals and care facilities.

No country for small birds: Potential positive association among medium‐sized, aggressive species in Australian bird communities

AbstractAimAustralian woodlands have been intensively cleared since European settlement and, in parallel, many species of birds inhabiting this habitat type have experienced a marked decline. Conversely, some species such as noisy miner Manorina melanocephala respond positively to habitat disturbance and due to their hyper‐aggressiveness can end up driving away specialized and fragmentation‐sensitive species. Recent studies have suggested that the negative impact of miners is exacerbated by means of synergistic interactions between these and other aggressive species, including nest predators. However, it is not clear if these positive associations arise through similar habitat requirements or due to potential mutual benefits (‘facilitation effects’), which should predominate in harsh environments as the stress‐gradient hypothesis (SGH) predicts.LocationEastern Australia.MethodsWe combined a multi‐season community N‐mixture model and joint species distribution models within the Hierarchical Modelling of Species Communities framework to examine species co‐occurrence patterns after accounting for imperfect detection and the influence of environmental variables. We then explored how the balance between positive and negative associations varied along an abiotic stress gradient and whether species‐to‐species associations were non‐randomly distributed with respect to species traits.ResultsNo significant associations were detected; we only found tentative associations (posterior probability 85%) in a low proportion of species pairs (~4%). Although most non‐random (tentative) associations were negative, these were weaker and less consistent across models than the positive ones. Five medium‐sized species of swooping birds including the noisy miner monopolized virtually all positive associations. Communities from low‐productivity environments tended to show a lower degree of overall (community‐level) competitiveness than those located in less stressful (more productive) environments, which supports the SGH. There was no significant relationship between species trait dissimilarity and species‐to‐species association's strength.Main ConclusionsOur results suggest that aggressive species like miners, kookaburras, lorikeets, magpies and butcherbirds can form potential synergies with each other that may intensify the direct negative influence of each species on small‐sized songbirds. Since these species thrive in anthropized landscapes and have drastically increased their numbers in some regions, their associative potential should be considered in conservation actions.

Grasping hold of functional trade-offs using the diversity of foot forms in Australian birds

The remarkable diversity of ecological niches that birds have evolved to inhabit have resulted in their status as model organisms to study how the same morphological features can adapt to different environments. Not least of these features is the avian foot, which has diversified into a wide range of forms suited to several different ecological functions. In this investigation, we examine how a potential trade-off between two such functions is expressed in the foot morphology of the Australian avifauna; namely, the impact that specialising for either walking or grasping has on the proportions of the phalanges. The lengths of the body, foot, third digit and its phalanges, and the hallux were recorded from 106 preserved skins belonging to 22 species. Our analysis of these data shows that this functional specialisation presents a similar morphological gradient in Australian birds as has been previously observed in American species, with a few unique exceptions. Generally, species that are reliant on the foot to grasp (e.g., perching and gripping prey) display greater distal phalanx and hallux lengths than species that are specialised for walking or wading. However, the terrestrial Megapodes of Australia demonstrate a more intermediate morphology, potentially as a result of the unique mound construction behaviour occurring in this clade. These findings have relevance not only for use in identifying the ecology of cryptic or extinct species from morphology, but also for determining future evolutionary changes in different avian groups.

Birds as buddies: the politics of sentimentality in the Birds in backyards (Australia) Facebook site

ABSTRACT This paper takes up Howard’s (1999) suggestion that sentimentality can be a lens on self-world relations. It focuses on human-bird relations in a Facebook site dedicated to Australian wild birds: Birds in Backyards (Australia). We argue that the traditional ideal of intellectual and affective distance through which critiques of sentimentality are still so often couched is not very useful in understanding and valuing the dynamic, interactive and immersive forms of social media. A study of Birds in Backyards suggests that there quite different ways that the love of wild birds can manifest and that sentimentality is not inimical to the generation of a community of care for, and celebration of, birds. Moreover, an older assumption that sentimentality might be the opposite of, or an impediment to, practical action seems hard to justify in the discursively and emotionally complex milieux of the digital age. Today, there is no place for an opposition between feeling and doing, and scientific action often requires and mobilizes emotion.