The population genetics of the western purple-crowned fairy-wren (Malurus coronatus coronatus), a declining riparian passerine

We investigate the population genetic structure of the declining western subspecies of the purple-crowned fairy-wren (Malurus coronatus coronatus) in order to guide conservation management recommendations for this riparian habitat specialist. Our analysis of multilocus microsatellite data, from 79 individuals sampled from across the species’ range, indicates that M. c. coronatus occurs as genetically differentiated subpopulations that correspond to catchment boundaries or expansive gaps in habitat along waterways. The genetic similarity of large populations of fairy-wrens on four catchments (Fitzroy, Durack, Drysdale and Victoria) indicates widespread recent gene flow, whereas the high genetic distinctiveness of the Bindoola and Isdell catchments may reflect the current geographic isolation of these smaller populations. Genetic differentiation of these smaller geographically isolated populations affirms the negative effect that habitat degradation and fragmentation can have on population connectivity. A regional-scale approach to conservation with a focus on preventing degradation and enhancing connectivity may be critical to safeguard the persistence of M. c. coronatus subpopulations.

EcoFire: regional-scale prescribed burning increases the annual carrying capacity of livestock on pastoral properties by reducing pasture loss from wildfire

Prescribed burning is an important management tool in the extensive pastoral lands in northern Australia. It can be used to influence grazing patterns, increase the nutritive value of pastures, reduce the density of woody shrubs and reduce the risk of damaging wildfires. The consequences of regional-scale prescribed burning on pasture availability and annual carrying capacities of pastoral properties in northern Australia were examined using EcoFire, a fire management program in the Kimberley Region of north-west Australia, as an example. Theoretical long-term carrying capacities of land systems, and fire scar imagery from years before (2004–06) and during EcoFire (2007–11) were used to model the impact of the program on the seasonality and extent of fire-induced losses in annual carrying capacity, and the likelihood of properties experiencing catastrophic losses in a given year. Over the 5 years that EcoFire has been running, it has resulted in a progressive reduction in the loss of annual carrying capacity caused by the burning of pasture, and shifted the season that annual carrying capacity is lost to fire from predominantly the late to the early dry season. Most notably, the established program has reduced the probability of experiencing catastrophic loss (defined here as >50% of annual carrying capacity removed due to fire) from 18 incidences to three incidences within a 3-year period. These outcomes have the potential to deliver economic benefits to pastoralists via increased annual carrying capacity and by improvements in pasture condition, provided stocking rates and pasture utilisation are managed carefully.

Conservation of the patchily distributed and declining purple-crowned fairy-wren (Malurus coronatus coronatus) across a vast landscape: the need for a collaborative landscape-scale approach

Conservation of species that are patchily distributed must consider processes that influence both the occurrence of individuals within patches, and the persistence of populations across multiple habitat patches within the landscape. Here we present a rare regional assessment of the population size and distribution of a patchily distributed, threatened species, the purple-crowned fairy-wren (Malurus coronatus coronatus), across a vast landscape. We used data from aerial vegetation mapping of waterways, with on-ground bird surveys to predict the occurrence of suitable habitat for M. c. coronatus across 14 catchments in the Kimberley region of Western Australia. Suitable habitat was extremely limited (305 km of riparian vegetation) and fragmented (342 patches) along the 2700 km of waterway surveyed within catchments where the species occurs. Populations were predicted to be large on the Fitzroy, Durack and Drysdale catchments, and small on the Isdell and northern Pentecost catchments, and a total population of 2834 to 4878 individuals could be supported. The sub-populations spanned numerous patches of habitat across multiple properties of varying tenure. Therefore, a landscape-scale approach to conservation management, across multiple tenures, is critical to safe-guard connectivity within populations. The greatest benefit may be achieved by a combination of broad-scale actions to reduce the impact of ubiquitous threatening processes, and fine-scale targeted effort in areas where populations are most vulnerable. Controlling access of stock to waterways and management of fire are most important to conserve suitable habitat. Such a landscape-scale approach to conservation may be of benefit to other patchily distributed species.

A way to reduce interference with Elliott traps

Elliott traps are widely used in Australia to capture small terrestrial mammals. However, in some situations non-target species disturb the traps, resulting in fewer traps being available for the target species. This situation occurred on Faure Island Wildlife Sanctuary (Western Australia) where boodies (burrowing bettongs) were disturbing the Elliott traps deployed to monitor populations of shark bay mice and western barred bandicoots. This note presents the method used to alleviate this problem on Faure Island but would be more widely applicable in other situations where Elliott traps are disturbed by animals other than the target species.

Variation in body condition indices of crimson finches by sex, breeding stage, age, time of day, and year

Body condition indices are increasingly applied in conservation to assess habitat quality, identify stressed populations before they decline, determine effects of disturbances, and understand mechanisms of declines. To employ condition indices in this manner, we need first to understand their baseline variability and sources of variation. Here, we used crimson finches (Neochmia phaeton), a tropical passerine, to describe the variation in seven commonly used condition indices by sex, age, breeding stage, time of day, and year. We found that packed cell volume, haemoglobin, total plasma protein, and scaled mass were all significantly affected by an interaction between sex and breeding stage. Furcular fat varied by sex and breeding stage and also trended by year, scaled mass showed a positive trend with age and varied by time of day, and haemoglobin additionally varied by year. Pectoral muscle scores varied and heterophil to lymphocyte ratio trended only by year. Year effects might reflect a response to annual variation in environmental conditions; therefore, those indices showing year effects may be especially worthy of further investigation of their potential for conservation applications. Pectoral muscle scores and heterophil to lymphocyte ratio may be particularly useful due to the lack of influence of other variables on them. For the other indices, the large variation that can be attributed to individual covariates, such as sex and breeding stage, suggests that one should not interpret the physiological condition of an individual as measured by these indices from their absolute value. Instead, the condition of an individual should be interpreted relative to conspecifics by sex, breeding stage, and possibly age.

Inferring population connectivity across the range of the purple-crowned fairy-wren (Malurus coronatus) from mitochondrial DNA and morphology: implications for conservation management

Knowledge of population structure and patterns of connectivity is required to implement effective conservation measures for the purple-crowned fairy-wren (Malurus coronatus), a threatened endemic of northern Australia. This study aimed to identify barriers to dispersal across the distribution of M. coronatus, investigate the impact that the recent declines may have on population connectivity, and propose conservation actions to maintain natural patterns of gene flow. Analysis of mitochondrial DNA sequences from 87 M. coronatus identified two phylogenetic clusters that corresponded with the phenotypically defined western (M. c. coronatus) and eastern (M. c. macgillivrayi) subspecies. The genetic divergence between these subspecies was consistent with isolation by a natural barrier to gene flow, and supports their separate conservation management. Within the declining M. c. coronatus, the lack of genetic divergence and only slight morphological difference between remnant populations indicates that populations were recently linked by gene flow. It is likely that widespread habitat degradation and the recent extirpation of M. c. coronatus from the Ord River will disrupt connectivity between, and dynamics within, remnant populations. To prevent further declines, conservation of M. coronatus must preserve areas of quality habitat and restore connectivity between isolated populations.

Spatial behaviour of yellow-footed rock-wallabies, Petrogale xanthopus, changes in response to active conservation management

Competition for food is predicted to influence faunal movement patterns as animals have to range further to satisfy their nutrient requirements. Research between 1979 and 1984 found that yellow-footed rock-wallabies, Petrogale xanthopus, in Middle Gorge, Buckaringa Sanctuary, had home ranges (134–169 ha in winter) that were much larger than predicted, which was attributed to competing livestock and cropping. We studied the ranging behaviour of this population using GPS telemetry after the cessation of farming and following several years of fox, Vulpes vulpes, and goat, Capra hircus, control to determine whether the reduction in competition and predation pressure has affected movement patterns of this endangered species. Mean winter range size of the four GPS-collared rock-wallabies was 4.3 ha (kernel or 5.5-ha MCP), which is a much smaller area than the rock-wallabies used before farming ceased and fox and goat control was implemented. The rock-wallabies primarily used the mid- to lower slopes of the gorge country and preferred redgum creeks and gorge habitats. The rock-wallabies exhibited a crepuscular activity pattern. We hypothesise that the difference in movements has arisen because the rock-wallabies are no longer competing for resources with introduced herbivores, and are able to meet their forage requirements from a smaller area.

The short-term effects of an extensive and high-intensity fire on vertebrates in the tropical savannas of the central Kimberley, northern Australia

We report the effects of an extensive (>7000 km2), high-intensity late-dry-season fire in the central Kimberley, Western Australia, on the species richness and abundance of mammals, reptiles and birds. Five weeks after the fire we surveyed 12 sites (six burnt, six unburnt); each pair of sites was closely matched for soil type and vegetation. The species richness and abundance of mammals and reptiles was greater at unburnt sites, especially for mammals (with a 4-fold difference in abundance between burnt and unburnt sites). There was an indication that reptiles immigrated into unburnt patches, but mammals did not. There were also species-specific responses to the fire: Rattus tunneyi and Pseudomys nanus were much more abundant in unburnt sites, whereas Pseudomys delicatulus was caught in equal numbers at burnt and unburnt sites. Diurnal reptiles were more abundant at unburnt sites, but nocturnal reptiles were equally common at burnt and unburnt sites. Avian species richness and overall abundance was similar between burnt and unburnt patches, although a few species showed preferences for one state or the other. The overall high trapping success for mammals (18% across all sites; 28% in unburnt patches) contrasts with the well documented mammal collapse in parts of northern Australia and seems paradoxical given that our study area has experienced the same increase in fire frequency and extent that is often blamed for species collapse. However, our study area has fewer pressures from other sources, including grazing by large herbivores, suggesting that the effects of these pressures, and their interaction with fire, may have been underestimated in previous studies.

Extreme Reversed Sexual Dichromatism in a Bird Without Sex Role Reversal

Brilliant plumage is typical of male birds, reflecting differential enhancement of male traits when females are the limiting sex. Brighter females are thought to evolve exclusively in response to sex role reversal. The striking reversed plumage dichromatism of Eclectus roratus parrots does not fit this pattern. We quantify plumage color in this species and show that very different selection pressures are acting on males and females. Male plumage reflects a compromise between the conflicting requirements for camouflage from predators while foraging and conspicuousness during display. Females are liberated from the need for camouflage but compete for rare nest hollows.

Effect of external stresses on protein conformation: a computer modelling study

The increasing use of digital technologies such as mobile phones has led to major health concerns about the effects of non-ionizing pulsed radiation exposure. We believe that the health implications of exposure to radiation cannot be fully understood without establishing the molecular mechanisms of biological effects of pulsed microwaves. We aim to establish methods for studying the molecular mechanisms of protein structural and energetic changes occurring due to external stresses related to non-ionizing radiation by using a combination of experimental and theoretical approaches. In this paper, we present the results from our fully atomistic simulation study of chemical and thermal stress response of a prototype protein, insulin. We performed a series of molecular dynamics simulations of insulin in solution under equilibrium conditions, under chemical stress (imitated by reducing the disulfide bonds in the protein molecule), and under short-lived thermal stress (imitated by increasing simulation temperature for up to 2 ns). The resultant protein conformational behaviour was analysed for various properties with the aim of establishing analysis routines for classification of protein unfolding pathways and associated molecular mechanisms.

Availability of nest hollows and breeding population size of eclectus parrots, Eclectus roratus, on Cape York Peninsula, Australia

The distribution of the Australian mainland endemic subspecies of the eclectus parrot, Eclectus roratus macgillivrayi, is currently confined to the lowland rainforests of the Iron–McIlwraith Ranges of eastern Cape York Peninsula. Females breed in large hollows in emergent rainforest trees that are readily visible from above. Aerial surveys were used to sample 58% of the rainforest (454 km2) of the Iron Range region to estimate the density of these nest trees. Corrections for overcounting bias (not all observed emergent trees were active nest trees) and undercounting bias (not all active nest trees were visible from the air) were made by ground-truthing over 70 trees. The tree count data were treated in two different ways, producing estimates of 417 (s.e. = 25) and 462 (s.e. = 31) nest trees for the Iron Range region. Long-term observational data on the number of eclectus parrots associated with each nest tree were used to estimate the population size of eclectus parrots at Iron Range: 538–596 breeding females, and 1059–1173 males. These results have three implications. First, this relatively low population estimate suggests that the Australian subspecies of eclectus parrots should be considered vulnerable to habitat loss or perturbation, especially in light of their complex social system, male-biased adult sex ratio, low breeding success and high variance in reproductive success among females. Second, the low density of nest trees suggests that eclectus parrots are absent from the rainforests of Lockerbie Scrub and the Jardine dunefields because these areas are too small. Finally, if eclectus parrots persisted in the Iron–McIlwraith region during the rainforest contractions of Pleistocene glacial maxima (e.g. 14 000–17 000 years ago), the refugium in this region must have been fairly substantial in order to support a viable population – probably larger than previously assumed.

Overlap and competition for nest holes among eclectus parrots, palm cockatoos and sulphur-crested cockatoos

We examined the extent of overlap in the characteristics of nest holes used by eclectus parrots (Eclectus roratus), palm cockatoos (Probosciger aterrimus) and sulphur-crested cockatoos (Cacatua galerita) in patches of rainforest and woodland in and around Iron Range National Park, Cape York Peninsula, Australia. Eclectus parrots nested only in rainforest and palm cockatoos nested mostly in eucalypt woodland adjacent to rainforest. Sulphur-crested cockatoos nested in both habitats. Nest holes of eclectus parrots and rainforest sulphur-crested cockatoos were in trees of larger DBH (diameter at breast height) and higher off the ground than those of palm cockatoos and sulphur-crested cockatoos in woodland. Palm cockatoos differed from the other parrots in their use of deeper holes with entrances that faced skywards rather than sideways. Both palm cockatoos and woodland sulphur-crested cockatoos used nests with smaller entrances than eclectus parrots and rainforest sulphur-crested cockatoos. All species showed intraspecific competition for nest holes. Behavioural conflict was also common between sulphur-crested cockatoos and the other two species. Each year 9.7–25.8% of eclectus parrot nests were taken over either permanently or temporarily by sulphur-crested cockatoos. Only one palm cockatoo nest was taken over by sulphur-crested cockatoos. Nest-holes were destroyed by natural causes at similar rates in rainforest (3.8% per annum over 174 nest-years) and woodland (5.4% per annum over 93 nest-years). Four nest trees fell over, and the floor of the nest collapsed at a further four holes. Three woodland nest trees burnt down during dry-season fires (August–October). New eclectus parrot and rainforest sulphur-crested cockatoo holes originated from incipient hollows on the tree that were modified by the parrots. We discuss the intense competition between these large parrots in light of the apparent shortage of appropriate nest holes in Cape York rainforest and eucalypt woodland.

Metallic orthopaedic implants and airport metal detectors

Airport security can detect in vivo metallic implants. We hypothesized that a soft tissue shield and fast transit through archway detectors would decrease implant detectability, whereas greater implant mass would increase detectability. Twelve patients with 8 orthopaedic implants in vivo and 60 trauma and arthroplasty implants in vitro were subjected to standard airport security measures at Stanstead Airport (British Airports Authority), including arch and standard and nonstandard hand-held detectors. Archway detectors failed to detect some implants; hand-held detectors detected almost all implants except an ankle arthroplasty. Positive archway detection was related to implant transit speed through the detection field. The implant mass consistently affected detection in stainless steel and titanium implants, and a 1-inch wax shield had no effect. Patients with metallic implants should prepare routinely with documentation of their implant before traveling through security ports.

Kingfishers in paradise: the breeding biology of Tanysiptera sylvia at the Iron Range National Park, Cape York

We describe the breeding biology and site fidelity of the buff-breasted paradise kingfisher (Tanysiptera sylvia), which migrates each year from New Guinea to breed in north-east Australia. In a three-year study at the Iron Range National Park in Cape York, Australia, we collected data from 91 breeding attempts (49 territories), and banded 77 adults and 101 nestlings (47 broods) to determine site fidelity. Paradise kingfishers arrived at Iron Range when the first major rains fell after the dry season. They nested exclusively in terrestrial termitaria, avoiding mounds that were too small, too close to a neighbouring territory, or mounds where the termites were absent. They were single-brooded, but laid a second clutch if their first attempt failed early. Clutch size was usually three, incubation lasted 25 days, nestlings hatched asynchronously and fledged after 27 days. Of 114 nestlings, 48.2% were male. Each breeding territory produced an average of 1.5 fledglings per year. The main factors influencing nesting success were predation, which ended 33% of all attempts, and brood reduction, which affected 24% of nests. Hatch failure was rare (3.2%). Birds were sexually mature at one year. Nearly half of the breeding adults banded in the first year of the study were still alive two years later, making them at least four years old. The return rates of banded adults varied among years (56–84%), but were similar for the two sexes. Returning birds almost always settled on the same territory with the same partner as the previous year, thus they formed long-term pair-bonds. In all, 7% of breeding pairs were assisted at the nest by an additional male, who was probably not their offspring.

Helper contributions in the cooperatively breeding laughing kookaburra: feeding young is no laughing matter

I studied the contributions of individuals to incubation and nestling feeding in a population of cooperatively breeding laughing kookaburras, Dacelo novaeguineae. In most cooperatively breeding birds where nest success is limited by nestling starvation, related helpers increase the overall level of provisioning to the nest, thus boosting the production of nondescendent kin. However, although partial brood loss is the largest cause of lost productivity in kookaburra nests, additional helpers failed to increase overall provisioning. Instead, all group members, but especially helpers, reduced their feeding contributions as group size increased. Breeders and helpers reduced the size of prey delivered, and helpers also reduced the number of feeding visits. An important benefit of helping in kookaburras may be to allow all group members to reduce their effort. Within groups, contributions to care depended on status, sex, group size and the brood size. Breeding males delivered the most food. Breeding females provisioned less than their partner, but their effort was comparable to that of male helpers. Female helpers contributed the least food. Incubation effort followed similar patterns. The relatedness of helpers to the brood had no impact on their provisioning. Across all group sizes, helpers generally brought larger items to the nest than breeders. Copyright 2000 The Association for the Study of Animal Behaviour.

Coalitions of relatives and reproductive skew in cooperatively breeding white-winged choughs

We used DNA fingerprinting to examine reproductive skew in cooperatively breeding white-winged choughs, Corcorax melanorhamphos, which live in groups of up to 20 individuals. Before a severe drought, groups that had been stable for multiple years were characterized by long-term monogamy involving a single breeding pair (high skew). After the drought, new groups formed from the amalgamation of multiple individuals and coalitions of relatives. At most one member of each faction succeeded in breeding, such that skew was dependent on the number of unrelated factions, and not group size. In the new groups, dominant males and females with supporting relatives were always successful. Whereas most females without support also gained breeding positions, many males without family support failed to breed. Thus subordinates gain indirect fitness by first helping related males to secure a breeding position, and then helping to raise their young. Our study demonstrates the advantage of operating in coalitions, and suggests that the acquisition of future allies may be a major benefit of helping behaviour in this species.

The cost of helping

Cooperative breeding in mammals, birds and fish has provided evolutionary biologists with a rich framework for studying the causes and consequences of group-based reproduction. Helping behaviour is especially enigmatic because it often entails an individual sacrificing personal reproduction while assisting others in their breeding attempts. The decision to help others to reproduce is affected by immediate and future costs analogous to those of direct reproduction, but these components of the equation have usually been neglected. Recent research suggests that the type of benefit sought could determine the extent of help given.