Optimizing survey effort for burrow-nesting seabirds

Regular monitoring of seabird populations is necessary to improve our understanding of their responses to environmental change and inform conservation management. However, given the difficulty in accessing remote breeding sites and the limited resources typically available to land managers, conducting regular, extensive surveys of seabird populations is often not feasible. Our objective was to determine the minimum survey effort required to obtain accurate and precise population estimates of Short-tailed Shearwaters (Ardenna tenuirostris) and Little Penguins (Eudyptula minor), two abundant burrowing seabird species in southeastern Australia, by comparing bootstrapped means and confidence intervals under different sampling regimes on four islands. We found that, in many cases, survey effort (the proportion of transects and quadrats along transects surveyed) could be reduced. For Short-tailed Shearwaters, reducing the number of transects resulted in a maximum difference of 15% between the means at full survey effort and two levels of reduced survey effort. Means differed by <3% when we halved the number of quadrats. For Little Penguins, reducing the number of transects and quadrats by 50% resulted in differences of 7-40% and 4-34%, respectively, between the full and reduced survey effort means. Confidence intervals generally increased with decreasing survey effort for both species. Differences in required survey effort between the two species in our study may have been due to differences in burrow distribution on islands, with Short-tailed Shearwater burrows generally uniformly distributed on each island and Little Penguin burrows typically occurring in patches. These would be influenced by island-specific characteristics in concert with habitat preferences, population size, and seasonal variation in seabird abundance. Stratified sampling did not increase survey accuracy and simulations showed that large reductions in survey effort could be made under a pseudo-random sampling regime, with mean abundance estimates similar at most levels of survey effort. For both species, reducing the proportion of pseudo-random quadrats to 50% and 25% of the full survey effort produced confidence intervals of 12% and 21%, respectively, of the maximum, whereas a survey effort of 10% produced confidence intervals of up to 36% of the maximum for both species. A pseudo-random sampling regime would maximize survey efficiency because considerably fewer quadrats would be required and allow development of more efficient sampling protocols and regimes.

Determining trends and environmental drivers from long-term marine mammal and seabird data : examples from Southern Australia

Climate change is acknowledged as an emerging threat for top-order marine predators, yet obtaining evidence of impacts is often difficult. In south-eastern Australia, a marine global warming hotspot, evidence suggests that climate change will profoundly affect pinnipeds and seabirds. Long-term data series are available to assess some species' responses to climate. Researchers have measured a variety of chronological and population variables, such as laying dates, chick or pup production, colony-specific abundance and breeding success. Here, we consider the challenges in accurately assessing trends in marine predator data, using long-term data series that were originally collected for other purposes, and how these may be driven by environmental change and variability. In the past, many studies of temporal changes and environmental drivers used linear analyses and we demonstrate the (theoretical) relationship between the magnitude of a trend, its variability, and the duration of a data series required to detect a linear trend. However, species may respond to environmental change in a nonlinear manner and, based on analysis of time-series from south-eastern Australia, it appears that the assumptions of a linear model are often violated, particularly for measures of population size. The commonly measured demographic variables exhibit different degrees of variation, which influences the ability to detect climate signals. Due to their generally lower year-to-year variability, we illustrate that monitoring of variables such as mass and breeding chronology should allow detection of temporal trends earlier in a monitoring programme than observations of breeding success and population size. Thus, establishing temporal changes with respect to climate change from a monitoring programme over a relatively short time period requires careful a priori choice of biological variables. © 2014 Springer-Verlag Berlin Heidelberg.

Corvids congregate to breeding colonies of a burrow-nesting seabird

Egg predation is a major cause of reproductive failure among birds, and can compromise the viability of affected populations. Some egg predators aggregate near colonially breeding birds to exploit the seasonal increase of prey resources. We investigated spatial and temporal variations in the abundance of an egg predator (little raven Corvus mellori; Corvidae) to identify whether ravens aggregate spatially or temporally to coincide with any of three potential prey species: burrow-nesting little penguin (Eudyptula minor; Spheniscidae), short-tailed shearwater (Ardenna tenuirostris; Procellariidae), and surface-nesting silver gull (Chroicocephalus novaehollandiae; Laridae). We derived spatially explicit density estimates of little ravens using distance sampling along line transects throughout a calendar year, which encompassed little penguin, short-tailed shearwater and silver gull breeding and non-breeding seasons. High raven abundance coincided temporally with penguin and gull egg laying periods but not with that of shearwaters. The spatial distribution of raven density corresponded with the little penguin colony but not with shearwater or gull colonies. Thus, the presence of little penguin eggs in burrows correlated strongly with little raven activity, and this implies that little ravens may have learnt to exploit the plentiful subsurface food resource of little penguin eggs. Corvid management may be required to maintain the viability of this socially and economically important penguin colony.

Out of sight but not out of mind: corvids prey extensively on eggs of burrow-nesting penguins

Context Egg depredation is a major cause of reproductive failure among birds and can drive population declines. In this study we investigate predatory behaviour of a corvid (little raven; Corvus mellori) that has only recently emerged, leading to widespread and intense depredation of eggs of a burrow-nesting seabird (little penguin; Eudyptula minor). Aims The main objective of this study was to measure the rate of penguin egg depredation by ravens to determine potential threat severity. We also examined whether penguin burrow characteristics were associated with the risk of egg depredation. Ravens generally employ two modes of predatory behaviour when attacking penguin nests; thus we examined whether burrow characteristics were associated with these modes of attack. Methods Remote-sensing cameras were deployed on penguin burrows to determine egg predation rates. Burrow measurements, including burrow entrance and tunnel characteristics, were measured at the time of camera deployment. Key results Overall, clutches in 61% of monitored burrows (n≤203) were depredated by ravens, the only predator detected by camera traps. Analysis of burrow characteristics revealed two distinct types of burrows, only one of which was associated with egg depredation by ravens. Clutches depredated by ravens had burrows with wider and higher entrances, thinner soil or vegetation layer above the egg chamber, shorter and curved tunnels and greater areas of bare ground and whitewash near entrances. In addition, 86% were covered by bower spinach (Tetragonia implexicoma), through which ravens could excavate. Ravens used two modes to access the eggs: they attacked through the entrance (25% of burrow attacks, n≤124); or dug a hole through the burrow roof (75% of attacks, n≤124). Burrows that were subject to attack through the entrance had significantly shorter tunnels than burrows accessed through the roof. Conclusions The high rates of clutch loss recorded here highlight the need for population viability analysis of penguins to assess the effect of egg predation on population growth rates. Implications The subterranean foraging niche of a corvid described here may have implications for burrow-nesting species worldwide because many corvid populations are increasing, and they exhibit great capacity to adopt new foraging strategies to exploit novel prey. Journal compilation

Slavoj Zizek: a little piece of the real

Contents: Introduction : locating Zizek as critical theorist -- 1. On Zizek's expanded notion of ideology -- 2. Western (European) modernity and its discontents -- 3. Lack in the other -- 4. Zizek's ticklish subject -- 5. Does Zizek have a critical social theory of contemporary capitalism? -- 6. Taking sides : what is left in Zizek? (the abyss of freedom?)

Some care, little responsibility? Promoting directors'and managers' legal accountability for Occupational Health and Safety in the workplace

Health and safety at work remains a serious and under-recognised problem in Australia. This paper argues for the importance of increasing the individual responsibility and accountability of senior managers and directors of corporations for the development and maintenance of occupational health and safety (OHS) standards in the workplace. In order to do so, the paper first sets out the range of statutory and general law duties and liabilities to which directors and senior managers are subject, considers to what extent these obligations have relevance in the OHS area and argues for the extension of these duties and liabilities in some circumstances. The paper then goes on to argue for a better legislative model for the legal responsibility of managers and officers, supported by the increased prosecution of individuals in appropriate circumstances, as well as acknowledging the benefits of a broader range of non-legal strategies to improve board level commitment to OHS that will influence corporate compliance overall.

The power of rhythm and words : from little things big things grow

Primary literacy teacher educators need to re-conceptualise the ways in which they work together to model effective interdisciplinary practice. This paper reports on such practice in a team teaching unit for postgraduate students undertaking the Bachelor of Teaching (Primary/Secondary) at Deakin University, Melbourne. The interdisciplinary (Social Education, Language and Music) unit, a first in the Faculty of Education was conceptualised to challenge both lecturer and student (local and international) to 'rethink' their understandings of pedagogy, multi-literacies and teacher preparedness. For the purpose of this paper, the authors reflect on a particular team teaching experience whereby a text (song) was used to teach both the elements of music and literacy pedagogy. It opened up new possibilities for students to engage and participate with each discipline as well as how one area can inform and further deepen the understanding for learners of the other. For example, musical notation and score was used to explain and use the 4 resource model (Luke and Freebody, 1990). The authors contend that crossdisciplinary work cannot be reduced to simple cooperation among disciplines but that primary literacy teacher educators need to develop new conceptual frameworks for learning that will enhance their understandings of pedagogy and assist in preparing teachers in a challenging world.

So much to do, so little time: multicultural practices and Australian school music

In this paper, the authors are concerned with the challenges, dilemmas and choices that teachers face when teaching multicultural music in classrooms in Australia in an already overcrowded curriculum. This paper considers the notion of changing and shifting cultures, looking at how teachers can break out of the familiar paradigms in which they were trained. There will be a consideration of the notion of cultural ownership questioning whose music is to be taught, how is it to be taught, and by whom. A discussion of how music is embedded in the culture that creates it is undertaken in relation to the concepts of authenticity and transmission. The authors contend that the exploration of other cultures enables the making of connections within and without the classroom and beyond the school into the local, national and global arenas. It is our position that teachers should not hesitate to explore other musics and cultures. It is noted that teachers need support to do this which can only enhance both their teaching and the learning of their students even though there is so much to do in so little time.

A preliminary study of bryophytes and invertebrates of soil crusts in the Little Desert National Park and surrounds

This study is preliminary to ongoing investigations of soil crusts and associated invertebrates in north-west Victoria, focusing on the Little Desert National Park. Ninety quadrats from nine sites were sampled. Eighteen bryophyte species (nine mosses, nine liverworts) were identified within the quadrats. All invertebrates were from the Phylum Arthropoda. Overall abundance and diversity of invertebrates was low. While sampling in the drier months is valuable for observing the dynamics of soil crusts in this region, a more comprehensive assessment of species diversity is gained by sampling
during wetter periods.