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The fossil record for Cretaceous birds in Australia has been limited to rare skeletal material, feathers, and two tracks, a paucity shared with other Gondwanan landmasses. Hence the recent discovery of 27 avian footprints and other traces in the Early Cretaceous (Barremian-Aptian, 128–120 Ma) Wonthaggi Formation of Victoria, Australia amends their previous rarity there, while also confirming the earliest known presence of birds in Australia and the rest of Gondwana. The avian identity of these tracks is verified by their tridactyl forms, thin digits relative to track lengths, wide divarication angles, and sharp claws; three tracks also have hallux imprints. Track forms and sizes indicate a variety of birds as tracemakers, with some among the largest reported from the Early Cretaceous. Although continuous trackways are absent, close spacing and similar alignments of tracks on some bedding planes suggest gregariousness. The occurrence of this avian trace-fossil assemblage in circumpolar fluvial-floodplain facies further implies seasonal behavior, with trackmakers likely leaving their traces on floodplain surfaces during post-thaw summers. [ABSTRACT FROM AUTHOR]

Plumage divergence can function as a strong premating barrier when species come into secondary contact. When it fails to do so, the results are often genome homogenization and phenotypic hybrids at the zone of contact. This is not the case in the largely sympatric masked woodswallow and white‐browed woodswallow species (Passeriformes: Artamidae: Artamus spp) complex in Australia where phenotypic integrity is sustained despite no discernible mitochondrial structure in earlier work. This lack of structure may suggest recent divergence, ongoing gene flow or both, and phenotypic hybrids are reported albeit rarely. Here, we further assessed the population structure and differentiation across the species' nuclear genomes using ddRAD‐seq. As found in the mitochondrial genome, no structure or divergence within or between the two species was detected in the nuclear genome. This coarse sampling of the genome nonetheless revealed peaks of differentiation around the genes SOX5 and AXIN1. Both are involved in the Wnt/β‐catenin signalling pathway, which regulates feather development. Reconstruction of demographic history and estimation of parameters supports a scenario of secondary contact. Our study informs how divergent plumage morphs may arise and be sustained despite whole‐genome homogenization and reveals new candidate genes potentially involved in plumage divergence. [ABSTRACT FROM AUTHOR]

The Chestnut-backed Button-quail Turnix castanotus is a small, cryptic, ground-dwelling species endemic to savanna ecosystems of northern Australia. Due to aspects of its ecology, cryptic plumage and behaviour, and the remoteness of most of its distribution, there are few published observations from the field documenting its breeding biology. The eggs were first described in 1856 and have subsequently been described by other authors. Two nests were detected in the Northern Territory in March 2021. We compare nesting events there with previous descriptions and museum collections. Our findings are mostly consistent with other literature on this species, but are inconsistent with two contemporary accounts, which we suggest are based on misidentification of Painted Button-quail T. varius. [ABSTRACT FROM AUTHOR]

Chloris virgata has become one of the most difficult glyphosate-resistant (GR) grass weeds in summer fallows in the eastern region of Australia. It germinates in several cohorts following rainfall events; therefore, growers are often tempted to wait for most of the weeds to emerge before herbicide application. However, by that time, some seedlings have reached an advanced stage and there is limited information on the efficacy and reliability of alternate herbicides when targeting large plants of GR C. virgata. A series of experiments were conducted to determine the efficacy of alternate herbicides for the control of GR C. virgata. Haloxyfop (80 g a.i. ha-1) on its own, in mixtures, or sequential applications of haloxyfop and paraquat or glufosinate provided 97 to 100% mortality of the 8–10 leaf stage plants. Glufosinate (1500 g a.i. ha-1) also provided complete control of plants at this growth stage. For larger plants at the 24–28 leaf stage, glufosinate, with or without additional tank-mixed adjuvants, generally did not provide full control, however did show very high levels of biomass reduction and panicle suppression at application rates of 750 or 1500 g a.i. ha-1. Haloxyfop (40 to 160 g a.i. ha-1) and clethodim (180 g a.i. ha-1) on their own achieved 96 to 100% mortality at this growth stage. When applied to large plants (40–50 leaf stage), a tank-mix of isoxaflutole plus paraquat demonstrated significantly higher levels of plant mortality and biomass reduction than either herbicide used alone, and this mixture appears to be synergistic when tested via the Colby equation for synergy or antagonism. Plant mortality was greater (83%) when isoxaflutole (75 g a.i. ha-1) plus paraquat (300 g a.i. ha-1) was taken up through the foliage and soil, compared with the foliage alone. This study identified alternative herbicide options for large plants of GR C. virgata. [ABSTRACT FROM AUTHOR]

Feather sucking, or feather licking, has been reported anecdotally by employees in the Australian meat chicken breeder industry, but scarcely in the scientific literature. Consequently, the causes and implications of this behavior in meat chicken breeding chickens is relatively unknown. We surveyed 17 industry experts to generate hypotheses about feather sucking behavior. We aimed to understand the frequency and when it occurs, and attempted to understand what may cause an "outbreak". The recruitment of participants was intentionally biased towards Australian perspectives; only 5 of the 17 participants were international. All participants, except 1, had seen feather sucking/licking behavior (94.1%) and most participants (80%) suggested that the behavior was most frequently observed during rearing. Participants presented varying concerns about this behavior, ranging from the perspective that it was "normal" and had no impact on welfare, to concerns about mating injuries due to damaged feathers, increased risk of feather pecking and cannibalism, and psychological stress indicated by expression of repetitive (seemingly) functionless behavior. "Feather licking," "feather sucking," "feather eating," and "feather pecking" were terms used interchangeably, leading to confusion by participants about the cause and implications of the target behavior. The most common factors reported as the cause were boredom (52.9%), nutritional deficiencies (47.1%), and feed restriction (41.2%) and more than 80% of respondents agreed that stress contributes to feather sucking. The outputs from this study reflect only a small, but expert, number of opinions on feather sucking/licking behaviors in the Australian meat chicken breeder industry. A systematic understanding of this behavior is needed to provide insight into causation and the implications for welfare., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Feathers play an important role in many aspects of avian ecology, including sexual selection, thermoregulation and flight. However, several external stressors can negatively impact plumage condition. Birds preen their feathers to maintain feather integrity throughout the year. For seabirds, preening is especially important to ensure waterproofing of the plumage. However, due to the difficulty of observing seabirds at sea, little is known of the time and energy expended in preening and how this may impact other activities in these species. In the present study, bird-borne video and tri-axial accelerometer data loggers were used to investigate preening in Australasian Gannets (Morus serrator) from two colonies in south-eastern Australia. Gannets spend a substantial proportion of their time at sea preening (25.5 ± 1.7%). No significant differences in preening activity were observed between the 3 years of study or between colonies. Average Vectorial Dynamic Body Acceleration (VeDBA, a proxy for energy expenditure) was significantly higher during preening (0.34 ± 0.02 g) than resting (0.25 ± 0.02 g), but less than for flying or foraging. These results highlight the importance of preening in terms of time and energy in this species. Furthermore, a positive relationship between the number of dives and at-sea preening suggests a negative impact of diving on plumage integrity and, thus, a potential additional time and energy constraint during periods of reduced food availability. [ABSTRACT FROM AUTHOR]

Free-range laying hen housing systems are prevalent in Australia and perceived by consumers to provide greater opportunities for the expression of natural behaviour resulting in higher hen welfare. However, all housing systems have both benefits and risks and scientific evidence is needed on the welfare outcomes of free-range systems. In this review, the scientific literature is summarised from the past 10 years, from research conducted within Australia or internationally with brown laying-hen strains kept in free-range systems. It compiles information on range use by laying hens, hen behaviour while on the range, factors that affect range use, and impacts of ranging on hen health and other aspects of welfare. Novel insights have come from the use of radio-frequency identification systems that allow tracking of individual hens and have shown that the majority of hens access the range with multiple visits across the day, but a small proportion of hens within most flocks choose to remain indoors. Hens also vary in which areas of the range they use, and provision of natural or man-made shelters can increase both range access and range distribution. Hens spend most of their time foraging while outdoors, but the types and frequencies of behaviours vary depending on the resources available and other factors. Range access can be linked to health benefits such as improved plumage condition and reduced footpad dermatitis but there are also health risks associated with free-range systems such as greater susceptibility to disease (e.g. spotty liver disease), heat stress, predation, and potentially parasites in comparison to loose or cage housing systems. Design of the range area, indoor shed, management practices and rearing environments can all influence how hens utilise free-range housing systems. Further research is crucially needed on the impact of ranging on hen welfare in variable Australian climatic conditions, encompassing intense heat and sunlight as well as cooler or wet environments. [ABSTRACT FROM AUTHOR]

Island organisms often evolve phenotypes divergent from their mainland counterparts, providing a useful system for studying adaptation under differential selection. In the white-winged fairywren (Malurus leucopterus), subspecies on two islands have a black nuptial plumage whereas the subspecies on the Australian mainland has a blue nuptial plumage. The black subspecies have a feather nanostructure that could in principle produce a blue structural color, suggesting a blue ancestor. An earlier study proposed independent evolution of melanism on the islands based on the history of subspecies divergence. However, the genetic basis of melanism and the origin of color differentiation in this group are still unknown. Here, we used whole-genome resequencing to investigate the genetic basis of melanism by comparing the blue and black M. leucopterus subspecies to identify highly divergent genomic regions. We identified a well-known pigmentation gene ASIP and four candidate genes that may contribute to feather nanostructure development. Contrary to the prediction of convergent evolution of island melanism, we detected signatures of a selective sweep in genomic regions containing ASIP and SCUBE2 not in the black subspecies but in the blue subspecies, which possesses many derived SNPs in these regions, suggesting that the mainland subspecies has re-evolved a blue plumage from a black ancestor. This proposed re-evolution was likely driven by a preexisting female preference. Our findings provide new insight into the evolution of plumage coloration in island versus continental populations, and, importantly, we identify candidate genes that likely play roles in the development and evolution of feather structural coloration., (© The Author(s) 2024. Published by Oxford University Press on behalf of Society for Molecular Biology and Evolution.)

Aim: Birds are often coloured yellow, olive, orange or red by carotenoids, which are plant pigments that are ingested with food. Here we test whether there are consistent patterns of intraspecific geographic variation in male carotenoid‐based plumage coloration linked to latitude, temperature, precipitation and primary productivity. It has been suggested that patterns of geographic variation should be different for yellow, compared to the metabolically derived red carotenoid‐based coloration, but this has not been tested. Location: Australia. Taxa: Forty‐nine randomly selected species of Australian passerine birds (Passeriformes), 30 with yellow and 19 with red carotenoid‐based plumage coloration. Methods: Carotenoid‐based plumage patches of male museum specimens were measured using reflectance spectrometry, and spectra analysed using models of avian colour vision. For each species, we used linear models to determine whether geographic variation in carotenoid‐based colour correlated with latitude, temperature, precipitation or primary productivity. To determine whether effects are consistent across species, we used phylogenetic meta‐analyses. Results: Although spatial environmental effects on carotenoid‐based plumage coloration varied across species, overall, species tended to have more saturated carotenoid‐based coloration at lower latitudes, and warmer regions. These effects applied mainly to resident species (as opposed to migratory or nomadic) and were stronger for red compared to yellow carotenoid‐based colours. We found no consistent effects of precipitation or primary productivity. Main conclusions: Geographic variation in male carotenoid‐based plumage coloration of Australian passerines is unlikely to be caused by variation in plant productivity (the ultimate source of carotenoids), and may be better explained by latitudinal gradients in the intensity of sexual selection or predation risk. Alternatively, temperature effects on red carotenoid‐based coloration may be driven by the hypothesized link between carotenoid and cellular metabolism. Latitudinal and temperature effects have the potential to generate perceivable differences in coloration across realistic spatial scales, contributing to divergence in visual signals. [ABSTRACT FROM AUTHOR]

The bowerbirds in New Guinea and Australia include species that build the largest and perhaps most elaborately decorated constructions outside of humans. The males use these courtship bowers, along with their displays, to attract females. In these species, the mating system is polygynous and the females alone incubate and feed the nestlings. The bowerbirds also include 10 species of the socially monogamous catbirds in which the male participates in most aspects of raising the young. How the bower-building behavior evolved has remained poorly understood, as no comprehensive phylogeny exists for the family. It has been assumed that the monogamous catbird clade is sister to all polygynous species. We here test this hypothesis using a newly developed pipeline for obtaining homologous alignments of thousands of exonic and intronic regions from genomic data to build a phylogeny. Our well-supported species tree shows that the polygynous, bower-building species are not monophyletic. The result suggests either that bower-building behavior is an ancestral condition in the family that was secondarily lost in the catbirds, or that it has arisen in parallel in two lineages of bowerbirds. We favor the latter hypothesis based on an ancestral character reconstruction showing that polygyny but not bower-building is ancestral in bowerbirds, and on the observation that Scenopoeetes dentirostris , the sister species to one of the bower-building clades, does not build a proper bower but constructs a court for male display. This species is also sexually monomorphic in plumage despite having a polygynous mating system. We argue that the relatively stable tropical and subtropical forest environment in combination with low predator pressure and rich food access (mostly fruit) facilitated the evolution of these unique life-history traits. [Adaptive radiation; bowerbirds; mating system, sexual selection; whole genome sequencing.] [ABSTRACT FROM AUTHOR]

Pathogens pose a major risk to wild host populations, especially in the face of ongoing biodiversity declines. Beak and feather disease virus (BFDV) can affect most if not all members of one of the largest and most threatened bird orders world-wide, the Psittaciformes. Signs of disease can be severe and mortality rates high. Its broad host range makes it a risk to threatened species in particular, because infection can occur via spill-over from abundant hosts. Despite these risks, surveillance of BFDV in locally abundant wild host species has been lacking. We used qPCR and haemagglutination assays to investigate BFDV prevalence, load and shedding in seven abundant host species in the wild in south-east Australia: Crimson Rosellas (Platycercus elegans), Eastern Rosellas (Platycercus eximius), Galahs (Eolophus roseicapillus), Sulphur-crested Cockatoos (Cacatua galerita), Blue-winged Parrots (Neophema chrysostoma), Rainbow Lorikeets (Trichoglossus moluccanus) and Red-rumped Parrots (Psephotus haematonotus). We found BFDV infection in clinically normal birds in six of the seven species sampled. We focused our analysis on the four most commonly caught species, namely Crimson Rosellas (BFDV prevalence in blood samples: 41.8%), Sulphur-crested Cockatoos (20.0%), Blue-winged Parrots (11.8%) and Galahs (8.8%). Species, but not sex, was a significant predictor for BFDV prevalence and load. 56.1% of BFDV positive individuals were excreting BFDV antigen into their feathers, indicative of active viral replication with shedding. Being BFDV positive in blood samples predicted shedding in Crimson Rosellas. Our study confirms that BFDV is endemic in our study region, and can inform targeted disease management by providing comparative data on interspecies variation in virus prevalence, load and shedding. [ABSTRACT FROM AUTHOR]

In Australia, free-range layer pullets are typically reared indoors, but adult layers go outdoors, and this mismatch might reduce adaptation in laying environments. Enrichments during rearing may optimise pullet development and subsequent welfare as adult free-range hens. In the outdoor environment, hens may have greater opportunities for exercise and natural behaviours which might contribute to improved health and welfare. However, the outdoor environment may also result in potential exposure to parasites and pathogens. Individual variation in range use may thus dictate individual health and welfare. This study was conducted to evaluate whether adult hens varied in their external and internal health due to rearing enrichments and following variation in range use. A total of 1386 Hy-Line Brown R chicks were reared indoors across 16 weeks with three enrichment treatments including a control group with standard housing conditions, a novelty group providing novel objects that changed weekly, and a structural group with custom-designed structures to increase spatial navigation and perching. At 16 weeks of age the pullets were moved to a free-range system and housed in nine identical pens within their rearing treatments. All hens were leg-banded with microchips and daily ranging was assessed from 25 to 64 weeks via radio-frequency identification technology. At 64-65 weeks of age, 307 hens were selected based on their range use patterns across 54 days up to 64 weeks: indoor (no ranging), low outdoor (1.4 h or less daily), and high outdoor (5.2-9 h daily). The external and internal health and welfare parameters were evaluated via external assessment of body weight, plumage, toenails, pecking wounds, illness, and post-mortem assessment of internal organs and keel bones including whole-body CT scanning for body composition. The control hens had the lowest feather coverage (p < 0.0001) and a higher number of comb wounds (P = 0.03) than the novelty hens. The high outdoor rangers had fewer comb wounds than the indoor hens (P = 0.04), the shortest toenails (p < 0.0001) and the most feather coverage (p < 0.0001), but lower body weight (p < 0.0001) than the indoor hens. High outdoor ranging decreased both body fat and muscle (both p < 0.0001). The novelty group had lower spleen weights than the control hens (P = 0.01) but neither group differed from the structural hens. The high outdoor hens showed the highest spleen (P = 0.01) and empty gizzard weights (P = 0.04). Both the rearing enrichments and ranging had no effect on keel bone damage (all P ≥ 0.19). There were no significant interactions between rearing treatments and ranging patterns for any of the health and welfare parameters measured in this study (P ≥ 0.07). Overall, rearing enrichments had some effects on hen health and welfare at the later stages of the production cycle but subsequent range use patterns had the greatest impact. [ABSTRACT FROM AUTHOR]

The Grey Falcon (Falco hypoleucos) is a desert-living species restricted to the dry centre of Australia. These falcons have a number of unique life-history adaptations that may be crucial for their survival in this harsh environment, but these may, conversely, confine them to these arid regions. In this study we investigated what Grey Falcon feather structure can reveal about the ecology of the species. Specifically, we tested UV reflectance and structural waterproofing of Grey Falcon feathers, and compared these properties across other Australian Falco species. Grey Falcon feathers did not reflect unique UV peaks, nor show any significant difference in structural waterproofing when compared with closely-related sympatric falcon species. This suggests that Grey Falcon feathers have no specific adaptations to prevent the impact of UV or water on their plumage, so feather structure evidently does not help explain the persistence of this species in arid Australia. We suggest that an exploration of the physiological and behavioural thermoregulatory capabilities of this species should provide further insights in understanding how these birds cope with their extreme environment and are confined there. [ABSTRACT FROM AUTHOR]

Bird plumage hosts a diverse microbial community, including microbes capable of degrading the β-keratin in feathers (i.e. feather-degrading bacteria). The prevalence and effects of feather-degrading bacteria have primarily been studied in the Northern Hemisphere, and knowledge of the occurrence of these bacteria on Southern Hemisphere bird species is lacking. We explored the prevalence of feather-degrading bacteria on wild birds in Australia by sampling feathers from 254 individuals representing 25 species. First, to determine the total plumage bacterial load, we sampled bacteria from three body regions and identified and enumerated three presumed feather-degrading Bacillus spp. (B. licheniformis, B. cereus, and B. subtilis) based on morphology. Second, we collected a feather from each bird and in laboratory tests confirmed the presence of feather-degrading bacteria. Third, we tested for a relationship between the number of presumed feather-degrading Bacillus spp. counted and the presence of feather-degrading bacteria on the following variables: habitat type, foraging behaviour, flocking status, and feather wear. We found 85% of birds sampled harboured presumed Bacillus spp. Of the feather samples that tested positive for Bacillus in lab experiments, 62% were confirmed as feather-degrading Bacillus spp. The total plumage bacterial load varied with habitat type, with birds in heath habitats harbouring fewer bacteria. This study is the first report of feather-degrading bacteria on the plumage of wild Australian birds in vivo. [ABSTRACT FROM AUTHOR]

Two species of orioles, namely the Olive-backed Oriole (Oriolus sagittatus) and the Yellow Oriole (O. flavocinctus), occur across northern Australia. In New Guinea, both are confined to the Trans-Fly region immediately north of Cape York Peninsula. They occur there in Melaleuca-dominated 'swamp savanna', which is neither eucalypt savanna nor rainforest typical of their Australian habitats. A readily identifiable specimen of the Olive-backed Oriole collected in 2014 from the Trans-Fly has a mitochondrial DNA ND2 haplotype identical with Yellow Orioles. Its dorsal plumage has traits typical of Yellow Orioles. We infer it to have been descended from a hybridisation event involving a female Yellow Oriole followed by successive generations of backcrossing with Olive-backed Orioles. Three aberrantly plumaged orioles from New Guinea's Trans-Fly region date from 1937, 1969 and 2014. The 1969 specimen appears to be an aberrant Yellow Oriole. Molecular data are similarly not available for the 1937 specimen but its plumage is suggestive of hybrid origin. The 2014 bird's ND2 haplotype is identical with some Olive-backed Orioles and is inferred to be descended from hybridisation involving a female Olive-backed Oriole. Integration of phenotypic and genetic data directs study to understand drivers underpinning an unusually high frequency of aberrantly plumaged orioles. [ABSTRACT FROM AUTHOR]

Chlamydia psittaci is a globally distributed veterinary pathogen with zoonotic potential. Although C. psittaci infections have been reported in various hosts, isolation and culture of Chlamydia is challenging, hampering efforts to produce contemporary global C. psittaci genomes. This is particularly evident in the lack of avian C. psittaci genomes from Australia and New Zealand. In this study, we used culture-independent probe-based whole-genome sequencing to expand the global C. psittaci genome catalogue. Here, we provide new C. psittaci genomes from two pigeons, six psittacines, and novel hosts such as the Australian bustard ( Ardeotis australis ) and sooty shearwater ( Ardenna grisea ) from Australia and New Zealand. We also evaluated C. psittaci genetic diversity using multilocus sequence typing (MLST) and major outer membrane protein ( omp A) genotyping on additional C. psittaci -positive samples from various captive avian hosts and field isolates from Australasia. We showed that the first C. psittaci genomes sequenced from New Zealand parrots and pigeons belong to the clonal sequence type (ST)24 and diverse 'pigeon-type' ST27 clade, respectively. Australian parrot-derived strains also clustered in the ST24 group, whereas the novel ST332 strain from the Australian bustard clustered in a genetically diverse clade of strains from a fulmar, parrot, and livestock. MLST and omp A genotyping revealed ST24/ omp A genotype A in wild and captive parrots and a sooty shearwater, whilst 'pigeon-types' (ST27/35 and omp A genotypes B/E) were found in pigeons and other atypical hosts, such as captive parrots, a little blue penguin/Kororā ( Eudyptula minor ) and a zebra finch ( Taeniopygia guttata castanotis ) from Australia and New Zealand. This study provides new insights into the global phylogenomic diversity of C. psittaci and further demonstrates the multi-host generalist capacity of this pathogen.

The microscopic characteristics of downy barbules of feathers can assist with species identification in forensic investigations, particularly when only minute fragments remain. Using light microscopy (LM) and scanning electron microscopy (SEM), we characterised the feather morphology of 62 species of birds from 18 Orders including representatives of all Orders found in Australia, except Sphenisciformes (penguins). We demonstrate that with a few notable exceptions, Australian birds display similar feather characteristics to their well-studied Northern hemisphere relatives. We also show that the microscopic characteristics of downy barbules can be used to differentiate these Orders. A more detailed investigation of 39 parrot species revealed substantial similarities among the species, indicating that microscopic characteristics could not differentiate among parrot species. However, there were some features (barbule length and macroscopic features, i.e. colour), that may provide clues as to the species of origin. Importantly, the microscopic feather characteristics provide investigators with a simple, fast and cost effective mechanism with which to test assertions about the potential species of origin. This may preclude the requirement for further more expensive testing (such as DNA analysis) or direct further testing towards a smaller, more targeted number of species, reducing the amount and cost of testing required. [ABSTRACT FROM PUBLISHER]

All known Australian records of Little Stint, Calidris minuta, from 1977 to 2013 with details sufficient to determine the plumage phase of each bird are examined. The results of this investigation indicate that most of the birds recorded were in their normal seasonal plumage condition and challenge previous statements that many Australian records are of Little Stints in 'reverse-cycle breeding plumage'. Also, the number of records suggests that a few Little Stints occur annually in Australia. [ABSTRACT FROM AUTHOR]

The article provides information on plumage aberrations in Australian birds described in the articles by P.-J. Guay, D. A. Potvin and R. W. Robinson, and C. B. Frith and T. Murphy published in the 2012 issue of the "Australian Field Ornithology." Leucism can be defined as the lack of melanin pigments from all or parts of the plumage due to the congenital and heritable absence of pigment cells. The white pattern in leucistic birds is often symmetrical due to the way the pigment cells migrate from their embryonic origin into the rest of the body. Causes for pigmentless feathers aside from leucism include progressive greying and non-heritable factors such as poison or food deficiency. As reported, the most common mutation in birds is brown.

The article describes the juvenile plumage of the Grey Goshawk in the tropical regions of Australia. The goshawks were monitored in an area closer to Darwin, Northern Territory, where they are known to have brown-tinged collars, brown-fringed upperparts, and wavier ventral barring. Observations showed that Grey Goshawks live in nests located at a mangrove forest in Northern Territory, where they prey on mangrove snakes. Adult Grey Goshawks are known to have grey wings like their young counterparts, although the latter have brown plumage, which is similar to the Brown Goshawk.

The Powerful Owl is an elusive species inhabiting the forests of mainland eastern Australia. Obtaining crucial information on aspects of their breeding behaviour and dispersal has proven extremely difficult, even though other aspects of their ecology are well studied. Here we use molecular methods to investigate the breeding behaviour and dispersal of the Powerful Owl in two different habitats: highly fragmented forest along the urban fringe and continuous forest. DNA profiles of Powerful Owls were obtained predominately from shed feathers collected opportunistically between 1995 and 2006. Seven breeding pairs of Powerful Owls were identified, from which shed feathers were collected during 2003, 2004 and 2005. By comparing DNA profiles, one pair of Owls was found to have occupied the same breeding site for 10 years (1995–2005). The dispersal or movements of five offspring from this pair was also determined to be either of two scenarios: (1) the juvenile moves from the natal territory; however, isn't breeding; and (2) the juvenile is recovered as part of a breeding pair. Two pairs of Owls breeding in the urban fringe habitat were closely related, but no incidences of extra-pair fertilisation were detected among pairs in either habitat. This study provides new information about the breeding behaviour and dispersal of the Powerful Owl, and shows the potential of using genetic data sourced from shed feathers for studying cryptic, rare or elusive species. [ABSTRACT FROM AUTHOR]

Blood parasites rupture mature red blood cells and so reduce haemoglobin concentration and hence the potential activity levels of infected males. We examined blood parasites and haemoglobin concentration in the superb fairy-wren (Malurus cyaneus) across three years and six locations in South Australia. We tested the prediction that males in nuptial plumage have more blood parasites and hence lower haemoglobin concentration than males in eclipsed plumage. Of 188 birds, 20 (10.6%) had blood parasites (Haemaproteusspp). We found that (1) there was an effect of season and sex on haemoglobin concentration; (2) there was no effect of haemoglobin concentration on prevalence of blood parasites or intensity; and (3) males in nuptial plumage had more blood parasites but higher haemoglobin concentration than eclipsed males. [ABSTRACT FROM AUTHOR]

The existence of distinct traits in island versus mainland populations offers opportunities to gain insights into how eco-evolutionary processes operate under natural conditions. We used two island colonization events in the white-winged fairywren (Malurus leucopterus) to investigate the genomic and demographic origin of melanic plumage. This avian species is distributed across most of Australia, and males of the mainland subspecies (M. l. leuconotus) exhibit a blue nuptial plumage in contrast to males of two island subspecies - M. l. leucopterus on Dirk Hartog Island and M. l. edouardi on Barrow Island - that exhibit a black nuptial plumage. We used reduced-representation sequencing to explore differentiation and demographic history in this species and found clear patterns of divergence between mainland and island populations, with additional substructuring on the mainland. Divergence between the mainland and Dirk Hartog was approximately 10 times more recent than the split between the mainland and Barrow Island, supporting two independent colonizations. In both cases, estimated gene flow between the mainland and the islands was low, contributing to signals of divergence among subspecies. Our results present demographic reconstructions of mainland-island dynamics and associated plumage variation in white-winged fairywrens, with broader implications regarding our understanding of convergent evolution in insular populations., (© 2021 The Authors. Evolution © 2021 The Society for the Study of Evolution.)

Contamination of diverse environments and wild species by some contaminants is projected to continue and increase in coming decades. In the marine environment, large volumes of data to assess how concentrations have changed over time can be gathered from indicator species such as seabirds, including through sampling feathers from archival collections and museums. As apex predators, Flesh-footed Shearwaters (Ardenna carneipes) are subject to high concentrations of bioaccumulative and biomagnifying contaminants, and reflect the health of their local marine environment. We analysed Flesh-footed Shearwater feathers from Australia from museum specimens and live birds collected between 1900 and 2011 and assessed temporal trends in three trace elements of toxicological concern: cadmium, mercury, and lead. Concentrations of cadmium increased by 1.5% per year (95% CI: +0.6, +3.0), while mercury was unchanged through the time series (−0.3% per year; 05% CI: -2.1, +1.5), and lead decreased markedly (−2.1% per year, 95% CI: -3.2, −1.0). A reduction in birds' trophic position through the 20th century, and decreased atmospheric emissions were the likely driving factors for mercury and lead, respectively. By combining archival material from museum specimens with contemporary samples, we have been able to further elucidate the potential threats posed to these apex predators by metal contamination. Image 1 • Feathers from museums can be used to examine centennial patterns of contaminants. • Recent Flesh-footed Shearwaters have high concentrations of Cd, Hg, and Pb. • Cd increased, Pb decreased, and Hg remained stable from 1900 to 2011. • Some individuals exceeded hypothesized adverse effect levels. Cadmium in Flesh-footed Shearwater feathers increased between 1900 and 2011, while mercury remained stable and lead decreased. [ABSTRACT FROM AUTHOR]

The study of hybrid zones advances understanding of the speciation process, and approaches incorporating genomic data are increasingly used to draw significant conclusions about the impact of hybridisation. Despite the progress made, the complex interplay of factors that can lead to substantially variable hybridisation outcomes are still not well understood, and many systems and/or groups remain comparatively poorly studied. Our study aims to broaden the literature on avian hybrid zones, investigating a potentially geographically and temporally complex putative hybrid zone between two native Australian non-sister parrot species, the pale-headed and eastern rosellas (Platycercus adscitus and Platycercus eximius, respectively). We analysed six plumage traits and >1400 RADseq loci and detected hybrid individuals and an unexpectedly complex geographic structure. The hybrid zone is larger than previously described due to either observer bias or its movement over recent decades. It comprises different subregions where genetic and plumage signals of admixture vary markedly in their concordance. Evidence of contemporary hybridisation (later generation and backcrossed individuals) both within and beyond the previously defined zone, when coupled with a lack of F1 hybrids and differential patterns of introgression among potentially diagnostic loci, indicates a lack of post-zygotic barriers to gene flow between species. Despite ongoing gene flow, species boundaries are likely maintained largely by strong pre-mating barriers. These findings are discussed in detail and future avenues for research into this system are proposed, which would be of benefit to the speciation and hybrid zone literature.

The free range production system is becoming more common in Australia and is expected to increase. Free range hens are exposed to more stressors in comparison to hens from barn and cage systems and it is suggested that stress can increase bacterial shedding on eggs. The aims of this study were to examine the level of total bacteria and Enterobacteriaceae populations, as well as the presence of Salmonella and Campylobacter, in eggs collected from two free range flocks on two different farms and to conduct longitudinal observations of the behaviour and welfare of hens in the free range production system. Hen age (weeks) was shown to have a significant effect (increase) on the level of total bacteria on the egg shell surface and in shell pores, as well as having an effect on feather condition score. As the hens aged, the frequency of external visual egg characteristics increased, as did feather condition score (where feather condition was poorer). These observations indicate areas which should be investigated further to improve the food safety of eggs and optimise the welfare of free range hens., (Crown Copyright © 2016. Published by Elsevier Ltd. All rights reserved.)