Spatial variation in avian bill size is associated with temperature extremes in a major radiation of Australian passerines.

Morphology is integral to body temperature regulation. Recent advances in understanding of thermal physiology suggest a role of the avian bill in thermoregulation. To explore the adaptive significance of bill size for thermoregulation we characterized relationships between bill size and climate extremes. Most previous studies focused on climate means, ignoring frequencies of extremes, and do not reflect thermoregulatory costs experienced over shorter time scales. Using 79 species (9847 museum specimens), we explore how bill size variation is associated with temperature extremes in a large and diverse radiation of Australasian birds, Meliphagides, testing a series of predictions. Overall, across the continent, bill size variation was associated with both climate extremes and means and was most strongly associated with winter temperatures; associations at the level of climate zones differed from continent-wide associations and were complex, yet consistent with physiology and a thermoregulatory role for avian bills. Responses to high summer temperatures were nonlinear suggesting they may be difficult to detect in large-scale continental analyses using previous methodologies. We provide strong evidence that climate extremes have contributed to the evolution of bill morphology in relation to thermoregulation and show the importance of including extremes to understand fine-scale trait variation across space.

Shape-shifting: changing animal morphologies as a response to climatic warming.

Many animal appendages, such as avian beaks and mammalian ears, can be used to dissipate excess body heat. Allen's rule, wherein animals in warmer climates have larger appendages to facilitate more efficient heat exchange, reflects this. We find that there is widespread evidence of 'shape-shifting' (changes in appendage size) in endotherms in response to climate change and its associated climatic warming. We re-examine studies of morphological change over time within a thermoregulatory context, finding evidence that temperature can be a strong predictor of morphological change independently of, or combined with, other environmental changes. Last, we discuss how Allen's rule, the degree of temperature change, and other ecological factors facilitate morphological change and make predictions about what animals will show shape-shifting.

Too hot to handle? Behavioural plasticity during incubation in a small, Australian passerine.

Global warming and intensifying extreme heat events may affect avian reproductive success and costs, particularly in hot, arid environments. It is unclear how breeding birds alter their behaviour in response to rapid climate change, and whether such plasticity will be sufficient to offset rising temperatures. We examine whether a small, open-cup nesting, passerine - the Jacky Winter Microeca fascinans - in semi-arid Australia, exhibits similar levels of behavioural plasticity when incubating under high temperatures as low, and how heat impacts upon parental effort, body mass change and reproductive success. At high temperatures, female effort increased. Females doubled nest attendance between 28 °C and 40 °C, switching from incubating to shading eggs at approx. 30 °C. Egg-shading females panted to avoid hyperthermia. Panting increased with temperature and sun exposure. Male breeding effort was linked to temperature extremes. In cold conditions, males provisioned their mates heavily, buffering females from additional energetic costs, and males suffered a loss of body mass. In extreme heat, males helped shade eggs (although they never incubated). The likelihood of male egg-shading increased with temperature, but level of contribution was positively related to sun exposure. Hatching success declined with air temperatures >35 °C. Egg mortality reached 100 at air temperatures >42.5 °C. Parents continued to attend unviable eggs (for up to two weeks), suggesting egg-loss from heat exposure is a recent phenomenon. Although pairs exhibited considerable behavioural plasticity - including positioning nests to maximize afternoon shade - this was insufficient to counter extreme temperatures. In 2019, one hot day (45 °C) effectively terminated reproduction two months early, and was associated with a 50% decrease in reproductive success. The increasing frequency, intensity and earlier arrival of extreme heat events is likely to pose a major threat to avifauna populations in hot, arid environments, due to increased parental costs, reduced reproductive success and direct mortality.

The Skinner Burial of Ontario, Canada, and the Question of Paget's Disease in the Americas.

PURPOSE: To examine a possible case of Paget's disease of bone (PDB) in an Indigenous pre-contact male from Canada, individual D of the Skinner site in Ontario. METHODS: Radiographs, CT scan and histological analysis. RESULTS: The histological analysis revealed the mosaic pattern that characterizes PDB. CT scans show advanced sclerosis of the cranium and a diminished diplÓ§e with osteolytic lesions. CONCLUSIONS: The pathological features that have been identified are collectively characteristic of PDB. SIGNIFICANCE: The Skinner case advances our understanding of the global history and distribution of PDB. LIMITATIONS OF STUDY: Only two New World cases have been identified and neither has been studied in sufficient detail. SUGGESTIONS FOR FUTURE RESEARCH: The older individuals in precolonial New World skeletal series should be given CT scans, which are non-intrusive, to be followed by histological and genetic analyses when indicated.

Australian songbird body size tracks climate variation: 82 species over 50 years.

The observed variation in the body size responses of endotherms to climate change may be explained by two hypotheses: the size increases with climate variability (the starvation resistance hypothesis) and the size shrinks as mean temperatures rise (the heat exchange hypothesis). Across 82 Australian passerine species over 50 years, shrinking was associated with annual mean temperature rise exceeding 0.012°C driven by rising winter temperatures for arid and temperate zone species. We propose the warming winters hypothesis to explain this response. However, where average summer temperatures exceeded 34°C, species experiencing annual rise over 0.0116°C tended towards increasing size. Results suggest a broad-scale physiological response to changing climate, with size trends probably reflecting the relative strength of selection pressures across a climatic regime. Critically, a given amount of temperature change will have varying effects on phenotype depending on the season in which it occurs, masking the generality of size patterns associated with temperature change. Rather than phenotypic plasticity, and assuming body size is heritable, results suggest selective loss or gain of particular phenotypes could generate evolutionary change but may be difficult to detect with current warming rates.

Changing students' perceptions of the homeless: A community service learning experience.

The homeless are an underserved, local vulnerable population that can benefit from a service learning clinical practicum experience for baccalaureate prepared nursing students. Negative attitudes and disrespect among healthcare workers has been identified by the homeless as a barrier to healthcare. A service learning experience with a vulnerable population has been shown to change nursing students' attitudes and beliefs. A large university in a southern city partnered with a community based organization that provided services to the homeless to educate senior nursing students in a service learning experience. The goal of this project was to examine attitudes and perceptions of nursing students toward the homeless population before and after participation in a service learning clinical practicum experience. This case study utilized a pre and post experience questionnaire to collect qualitative data for the purposes of the project. The findings revealed students demonstrated a decrease in fear, an increase in empathy, and a deeper understanding of the advocacy role of nurses for people experiencing homelessness. Nurse educators are challenged to engage students with vulnerable populations to change the attitudes and perceptions for improvement in the overall health of communities served worldwide. Partnerships and service learning experiences can benefit all.

Effects of extreme weather on two sympatric Australian passerine bird species.

Despite abundant evidence that natural populations are responding to climate change, there are few demonstrations of how extreme climatic events (ECEs) affect fitness. Climate warming increases adverse effects of exposure to high temperatures, but also reduces exposure to cold ECEs. Here, we investigate variation in survival associated with severity of summer and winter conditions, and whether survival is better predicted by ECEs than mean temperatures using data from two coexisting bird species monitored over 37 years in southwestern Australia, red-winged fairy-wrens, Malurus elegans and white-browed scrubwrens, Sericornis frontalis Changes in survival were associated with temperature extremes more strongly than average temperatures. In scrubwrens, winter ECEs were associated with survival within the same season. In both species, survival was associated with body size, and there was evidence that size-dependent mortality was mediated by carry-over effects of climate in the previous season. For fairy-wrens, mean body size declined over time but this could not be explained by size-dependent mortality as the effects of body size on survival were consistently positive. Our study demonstrates how ECEs can have individual-level effects on survival that are not reflected in long-term morphological change, and the same climatic conditions can affect similar-sized, coexisting species in different ways.This article is part of the themed issue 'Behavioural, ecological and evolutionary responses to extreme climatic events'.

Are long-term widespread avian body size changes related to food availability? A test using contemporaneous changes in carotenoid-based color.

Recent changes in global climate have been linked with changes in animal body size. While declines in body size are commonly explained as an adaptive thermoregulatory response to climate warming, many species do not decline in size, and alternative explanations for size change exist. One possibility is that temporal changes in animal body size are driven by changes in environmental productivity and food availability. This hypothesis is difficult to test due to the lack of suitable estimates that go back in time. Here, we use an alternative, indirect, approach and assess whether continent-wide changes over the previous 100 years in body size in 15 species of Australian birds are associated with changes in their yellow carotenoid-based plumage coloration. This type of coloration is strongly affected by food availability because birds cannot synthesize carotenoids and need to ingest them, and because color expression depends on general body condition. We found significant continent-wide intraspecific temporal changes in body size (wing length) and yellow carotenoid-based color (plumage reflectance) for half the species. Direction and magnitude of changes were highly variable among species. Meta-analysis indicated that neither body size nor yellow plumage color showed a consistent temporal trend and that changes in color were not correlated with changes in size over the past 100 years. We conclude that our data provide no evidence that broad-scale variation in food availability is a general explanation for continent-wide changes in body size in this group of species. The interspecific variability in temporal changes in size as well as color suggests that it might be unlikely that a single factor drives these changes, and more detailed studies of museum specimens and long-term field studies are required to disentangle the processes involved.

Individual and demographic consequences of reduced body condition following repeated exposure to high temperatures.

Although the lethal consequences of extreme heat are increasingly reported in the literature, the fitness costs of exposure to sublethal high air temperatures, typically identified in the 30-40 degrees C range, are poorly understood. We examine the effect of high (> or = 35 degrees C) daily maxima on body condition of a semiarid population of White-plumed Honeyeaters, Ptilotula penicillatus, monitored between 1986 and 2012. During this 26-yr period, temperature has risen, on average, by 0.06 degrees C each year at the site, the frequency of days with thermal maxima > or = 35 degrees C has increased and rainfall has declined. Exposure to high temperatures affected body condition of White-plumed Honeyeaters, but only in low-rainfall conditions. There was no effect of a single day of exposure to temperatures > or = 35 degrees C but repeated exposure was associated with reduced body condition: 3.0% reduction in body mass per day of exposure. Rainfall in the previous 30 d ameliorated these effects, with reduced condition evident only in dry conditions. Heat-exposed males with reduced body condition were less likely to be recaptured at the start of the following spring; they presumably died. Heat-exposed females, regardless of body condition, showed lower survival than exposed males, possibly due to their smaller body mass. The higher mortality of females and smaller males exposed to temperatures > or = 35 degrees C may have contributed to the increase in mean body size of this population over 23 years. Annual survival declined across time concomitant with increasing frequency of days > or = 35 degrees C and decreasing rainfall. Our study is one of few to identify a proximate cause of climate change related mortality, and associated long-term demographic consequence. Our results have broad implications for avian communities living in arid and semiarid regions of Australia, and other mid-latitudes regions where daily maximum temperatures already approach physiological limits in regions affected by both decreased precipitation and warming.

Dynamic size responses to climate change: prevailing effects of rising temperature drive long-term body size increases in a semi-arid passerine.

Changes in animal body size have been widely reported as a correlate of contemporary climate change. Body size affects metabolism and fitness, so changing size has implications for resilience, yet the climatic factors that drive size variation remain poorly understood. We test the role of mean and extreme temperature, rainfall, and remotely sensed primary productivity (NDVI) as drivers of body size in a sedentary, semi-arid Australian passerine, Ptilotula (Lichenostomus)penicillatus, over 23 years. To distinguish effects due to differential growth from changes in population composition, we analysed first-year birds and adults separately and considered climatic variation at three temporal scales (current, previous, and preceding 5 years). The strongest effects related to temperature: in both age classes, larger size was associated with warmer mean temperatures in the previous year, contrary to Bergmann's Rule. Moreover, adults were larger in warmer breeding seasons, while first years was larger after heat waves; these effects are more likely to be mediated through size-dependent mortality, highlighting the role of body size in determining vulnerability to extinction. In addition to temperature, larger adult size was associated with lower primary productivity, which may reflect a trade-off between vegetative growth and nectar production, on which adults rely. Finally, lower rainfall was associated with decreasing size in first year and adults, most likely related to decreased food availability. Overall,body size increased over 23 years, strongly in first-year birds (2.7%) compared with adults (1%), with size outcomes a balance between competing drivers. As rainfall declined over time and productivity remained fairly stable, the temporal increase in body size appears largely driven by rising mean temperature and temperature extremes. Body size responses to environmental change are thus complex and dynamic, driven by effects on growth as well as mortality.

Morphometric measurements of dragonfly wings: the accuracy of pinned, scanned and detached measurement methods.

Large-scale digitization of museum specimens, particularly of insect collections, is becoming commonplace. Imaging increases the accessibility of collections and decreases the need to handle individual, often fragile, specimens. Another potential advantage of digitization is to make it easier to conduct morphometric analyses, but the accuracy of such methods needs to be tested. Here we compare morphometric measurements of scanned images of dragonfly wings to those obtained using other, more traditional, methods. We assume that the destructive method of removing and slide-mounting wings provides the most accurate method of measurement because it eliminates error due to wing curvature. We show that, for dragonfly wings, hand measurements of pinned specimens and digital measurements of scanned images are equally accurate relative to slide-mounted hand measurements. Since destructive slide-mounting is unsuitable for museum collections, and there is a risk of damage when hand measuring fragile pinned specimens, we suggest that the use of scanned images may also be an appropriate method to collect morphometric data from other collected insect species.

Declining body size: a third universal response to warming?

A recently documented correlate of anthropogenic climate change involves reductions in body size, the nature and scale of the pattern leading to suggestions of a third universal response to climate warming. Because body size affects thermoregulation and energetics, changing body size has implications for resilience in the face of climate change. A review of recent studies shows heterogeneity in the magnitude and direction of size responses, exposing a need for large-scale phylogenetically controlled comparative analyses of temporal size change. Integrative analyses of museum data combined with new theoretical models of size-dependent thermoregulatory and metabolic responses will increase both understanding of the underlying mechanisms and physiological consequences of size shifts and, therefore, the ability to predict the sensitivities of species to climate change.

Phylogeny and evolution of the Meliphagoidea, the largest radiation of Australasian songbirds.

The Meliphagoidea comprises the largest radiation of Australasian passerines. Here we present the first detailed molecular phylogenetic analysis of its families and genera, particularly the Acanthizidae, using sequences from nine gene regions including both mitochondrial and nuclear DNA. Our results support some suggested relationships but challenge other groupings, particularly in Meliphagidae and Acanthizidae. Maluridae is sister to all other members of the superfamily. With appropriate taxon sampling and multilocus data, we provide the first strong molecular evidence supporting earlier recognition of bristlebirds, Dasyornis, as a separate family, Dasyornithidae. We further clarify its position as sister to Acanthizidae+Pardalotidae+Meliphagidae. Pardalotidae is sister to Acanthizidae, and thus its retention as a separate family is arbitrary. The meliphagid genus Lichenostomus is polyphyletic. We find no support for the current subfamily structure within Acanthizidae but recognise a clade that includes members of the subfamily Sericornithinae excluding Oreoscopus and Acanthornis. Subfamily Acanthizinae is paraphyletic. Surprisingly, the Tasmanian island endemic Acanthornis magna of mesic habitats is sister to the Aphelocephala whitefaces of mainland Australian xeric zones. This is one of several unexpected alignments of taxa as sisters that probably reflects the age of the Meliphagoidea. We find no evidence for separate radiations of New Guinean and Australian members of the Meliphagoidea.

Shifting latitudinal clines in avian body size correlate with global warming in Australian passerines.

Intraspecific latitudinal clines in the body size of terrestrial vertebrates, where members of the same species are larger at higher latitudes, are widely interpreted as evidence for natural selection and adaptation to local climate. These clines are predicted to shift in response to climate change. We used museum specimens to measure changes in the body size of eight passerine bird species from south-eastern Australia over approximately the last 100 years. Four species showed significant decreases in body size (1.8-3.6% of wing length) and a shift in latitudinal cline over that period, and a meta-analysis demonstrated a consistent trend across all eight species. Southern high-latitude populations now display the body sizes typical of more northern populations pre-1950, equivalent to a 7 degrees shift in latitude. Using ptilochronology, we found no evidence that these morphological changes were a plastic response to changes in nutrition, a likely non-genetic mechanism for the pattern observed. Our results demonstrate a generalized response by eight avian species to some major environmental change over the last 100 years or so, probably global warming.

Recognition of other species' aerial alarm calls: speaking the same language or learning another?

Alarm calls given by other species potentially provide a network of information about danger, but little is known about the role of acoustic similarity compared with learning in recognition of heterospecific calls. In particular, the aerial 'hawk' alarm calls of passerines provide a textbook example of signal design because many species have converged on a design that thwarts eavesdropping by hawks, and call similarity might therefore allow recognition. We measured the response of fairy-wrens (Malurus cyaneus) to playback of acoustically similar scrubwren (Sericornis frontalis) aerial alarm calls. First, if call similarity prompts escape independent of learning, then fairy-wrens should flee to playback of scrubwren calls outside their geographical range. However, fairy-wrens fled only in sympatry. Second, if call similarity is necessary for learning heterospecific calls, then fairy-wrens should not respond to sympatric species with different calls. We found, on the contrary, that fairy-wrens fled to the very different aerial alarm calls of a honeyeater (Phylidonyris novaehollandiae). Furthermore, response to the honeyeater depended on the specific structure of the call, not acoustic similarity. Overall, call similarity was neither sufficient nor necessary for interspecific recognition, implying learning is essential in the complex task of sifting the acoustic world for cues about danger.

Comparison of methods to facilitate postoperative bowel function.

Improving postoperative return of bowel function after abdominal surgery is an important nursing and medical goal. One promising intervention to achieve this goal is to have patients chew gum several times per day in the early postoperative period to stimulate the cephalic-vagal reflex and bowel peristalsis. A study to determine if return of gastrointestinal function after abdominal surgery could be hastened by the simple intervention of chewing gum or sucking on hard candy three times per day is described.