The role of intense net predation in the decline of Scarlet Robins and Eastern Yellow Robins in remnant woodland near Armidale, New South Wales

A study of open-nesting Eastern Yellow Robins 'Eopsaltria australis' and Scarlet Robins 'Petroica multicolor', on the New England Tablelands of New South Wales in 2000-02, found low breeding success typical of eucalypt woodland birds. The role of intense nest predation in the loss of birds from woodland fragments was investigated by means of predator-exclusion cages at robin nests, culling of Pied Currawongs 'Strepera graculina', and monitoring of fledging and recruitment in the robins. Nest-cages significantly improved nest success (86% vs 20%) and fledging rate (1.6 vs 0.3 fledglings per attempt) for both robin species combined (n = 7 caged, 20 uncaged). For both robin species combined, culling of currawongs produced a twofold difference in nest success (33% vs 14%), a higher fledging rate (0.5 vs 0.3 per attempt), and a five-day difference in mean nest survival (18 vs 13 days) (n = 62 nests), although sample sizes for nests in the cull treatment (n = 18) were small and nest predation continued. Although the robin breeding population had not increased one year after the cull, the pool of Yellow Robin recruits in 2001-03, after enhanced fledging success, produced two emigrants to a patch where Yellow Robins had become extinct. Management to assist the conservation of open-nesting woodland birds should address control of currawongs

Breeding biology and behaviour of the Scarlet Robin 'Petroica multicolor' and Eastern Yellow Robin 'Eopsaltria australis' in remnant woodland near Armidale, New South Wales

The breeding biology and behaviour of the Scarlet Robin 'Petroica multicolor' and Eastern Yellow Robin 'Eopsaltria australis' were studied at Imbota Nature Reserve, on the New England Tableland of New South Wales, in 2000-2002 by colour-banding and nest-monitoring. Yellow Robins nested low in sheltered positions, in plants with small stem diameters (mostly saplings, live trees and shrubs), whereas Scarlet Robins nested high in exposed positions, in plants with large stem diameters (mostly live trees, dead branches or dead trees). Yellow Robin clutch size was two or three eggs (mean 2.2; n = 19). Incubation and nestling periods were 15-17 days and 11-12 days respectively (n = 6) for the Yellow Robin, and 16-18 days (n = 3) and 16 days (n = 1) respectively for the Scarlet Robin. Both species were multi-brooded, although only Yellow Robins successfully raised a second brood. The post-fledging dependence period lasted eight weeks for Yellow Robins, and six weeks for Scarlet Robins. The two robins appear to differ in their susceptibility to nest predation, with corresponding differences in anti-predator strategies

Breeding and population parameters of robins in a woodland remnant in northern New South Wales, Australia

Savanna ecosystems are characterized by the co-occurrence of trees and grasses. In this paper, we argue that the balance between trees and grasses is, to a large extent, determined by the indirect interactive effects of herbivory and fire. These effects are based on the positive feedback between fuel load (grass biomass) and fire intensity. An increase in the level of grazing leads to reduced fuel load, which makes fire less intense and, thus, less damaging to trees and, consequently, results in an increase in woody vegetation. The system then switches from a state with trees and grasses to a state with solely trees. Similarly, browsers may enhance the effect of fire on trees because they reduce woody biomass, thus indirectly stimulating grass growth. This consequent increase in fuel load results in more intense fire and increased decline of biomass. The system then switches from a state with solely trees to a state with trees and grasses. We maintain that the interaction between fire and herbivory provides a mechanistic explanation for observed discontinuous changes in woody and grass biomass. This is an alternative for the soil degradation mechanism, in which there is a positive feedback between the amount of grass biomass and the amount of water that infiltrates into the soil. The soil degradation mechanism predicts no discontinuous changes, such as bush encroachment, on sandy soils. Such changes, however, are frequently observed. Therefore, the interactive effects of fire and herbivory provide a more plausible explanation for the occurrence of discontinuous changes in savanna ecosystems

Breeding-habitat and nest-site characteristics of Scarlet Robins and Eastern Yellow Robins near Armidale, New South Wales

I studied the selection of breeding habitat and nest microhabitat in Scarlet Robins 'Petroica multicolor' and Eastern Yellow Robins 'Eopsaltria australis', in remnant woodland on the New England Tablelands of New South Wales in 2000-2002. Yellow Robins used breeding territories (n = 10) with significantly higher densities of rough-barked saplings, acacias and other (non-Acacia) shrubs than Scarlet Robin breeding territories (n = 10) and plots lacking Yellow Robins (n = 7). Yellow Robins nested mostly in gully and lower-slope positions, with a southerly aspect, >40 m from the woodland edge, whereas Scarlet Robins nested mostly on upper slopes and ridges, with no preferred minimum distance from the woodland edge. Most Yellow Robin nests (86% of 58) had overhead foliage within 1 m, shielding them from above, whereas over half (58% of 54) of Scarlet Robin nests were in unconcealed positions. Yellow Robin nests had significantly greater density of cover, and the surrounding habitat was more complex, than for Scarlet Robin nests, in 0.13-ha plots centred on the nest. Breeding success and fledgling survival in the Yellow Robin were positively related to the density of acacias, non-Acacia shrubs and rough-barked saplings (but not gum saplings) in breeding territories. Fledging success and juvenile survival in the Yellow Robin were also positively related to habitat complexity around nest-sites (but not distance to nearest cover, or items of cover within 20 m). Scarlet Robins had exposed nests and suffered high nest predation, with too few successful nests for comparison with unsuccessful nests. Habitat conservation for the Yellow Robin should address the complexity of the ground, shrub and sapling layer in woodland remnants; that for the Scarlet Robin may need to address foraging substrate and ecologically based control of nest predators

The Birds of Bulgunnia and Mulyungarie Stations in the Pastoral Zone of Arid South Australia

A list of birds observed on Bulgunnia Station (Lake Torrens/Lake Gairdner Basin) and Mulyungarie Station (lower North East), in spring 1997 and each spring and autumn from November 2002 to May 2005, is provided. Brief notes are given on selected species, including the Grey Falcon Falco hypoleucos, Plains-wanderer 'Pedionomus torquatus' and Chestnut-breasted Whiteface 'Aphelocephala pectoralis', and an undescribed call of the Chirruping Wedgebill 'Psophodes cristatus'

Neuroendocrine correlates of sex-role reversal in barred buttonquails

Supplementary Figure S1: Autoradiograms of coronal sections through the brain of a female (Panels A-L) and male (Panels M-X) buttonquail at hatching day (P0) illustrating the expression of AR, ERα, ERβ and ARO mRNA visualised by in situ hybridisation. For each gene, sections are presented in a rostral to caudal order. Panels A-D and M-P are at the level of the anterior commissure. Panels I-L and U-X are at the level of the caudal hypothalamus. Abbreviations: BSTM, bed nucleus of the stria terminalis; CA, commisura anterior; ICo, nucleus intercollicularis; LS, lateral septum; MBH, mediobasal hypothalamus; POM, medial preoptic nucleus; TnA, nucleus taeniae of the amygdala.Supplementary Video S1: Sequence showing the performance of the booming call by a female barred buttonquail.Supplementary Video S2: Sequence showing the performance of a chase by a female barred buttonquail.Supplementary Video S3: Sequence showing the performance of courtship feeding by a female buttonquail.Sex differences in brain structure and behaviour are well documented among vertebrates. An excellent model exploring the neural mechanisms of sex differences in behaviour is represented by sex-role-reversed species. In the majority of bird species, males compete over access to mates and resources more strongly than do females. It is thought that the responsible brain regions are therefore more developed in males than in females. Because these behaviours and brain regions are activated by androgens, males usually have increased testosterone levels during breeding. Therefore, in species with sex-role reversal, certain areas of the female brain should be more developed or steroid hormone profiles should be sexually reversed. Here, I studied circulating hormone levels and gene expression of steroid hormone receptors and aromatase in a captive population of barred buttonquails (Turnix suscitator). While females performed courtship and agonistic behaviours, there was no evidence for sexually reversed hormone profiles. However, I found female-biased sex differences in gene expression of androgen receptors in several hypothalamic and limbic brain regions that were already in place at hatching. Such sex differences are not known from non-sex-role-reversed species. These data suggest that increased neural sensitivity to androgens could be involved in the mechanisms mediating sex-role-reversed behaviours.This study was funded by grants Vo1506/2-1 and Vo1506/3-1 from Deutsche Forschungsgemeinschaft (DFG).http://rspb.royalsocietypublishing.org2017-11-30hb2017Zoology and Entomolog

Modelling Workflows for More-than-Human Design: Prosthetic Habitats for the Powerful Owl (Ninox strenua)

Anthropogenic degradation of the environment is pervasive and expanding. Human construction activities destroy or damage habitats of nonhuman lifeforms. In many cases, artificial replacement habitats become necessary. However, designing for the needs and preferences of nonhuman lifeforms is challenging. Established workflows for this type of designing do not exist. This paper hypothesises that a multi-scale modelling approach can support inclusive, more-than-human design. The case-study project tests this approach by applying computational modelling to the design of prosthetic habitats for the powerful owl (Ninox strenua). The proposed approach simulates owls’ perception of the city based on scientific evidence. The tools include algorithmic mapping, 3D-scanning, generative modelling, digital fabrication and augmented-reality assembly. Outcomes establish techniques for urban-scale planning, site selection, tree-scale fitting, and nest-scale form-making. The findings demonstrate that computational modelling can (1) inform more-than-human design and (2) guide scientific data collection for more inclusive ecosystem management