White-throated Treecreeper Research Articles

Pronounced daily heterothermy in the White-throated Treecreeper Cormobates leucophaea

Torpor, a controlled reduction in metabolism and body temperature, reduces energy expenditure substantially. However, torpor expression in wild passerines is currently understudied. We show that skin temperature (Ts) of resting White-throated Treecreepers (N = 4) fell by ~ 5 °C on average in both summer and winter, independent of ambient temperature, but we could not confirm torpor use (Ts reduction > 5 °C). It is possible that roosting in tree hollows provides sufficient insulation to minimise energy loss, or torpor is used only during extreme conditions. Further studies are needed to characterise the physiological flexibilities of species and, therefore, their capability to cope with changing environmental conditions.

Prescribed burn severity has minimal effect on common bird species in a fire-prone forest ecosystem

Prescribed burning is widely used to mitigate the effects of severe fires across the landscape and to maintain biodiversity. Just like wildfires, the severity of prescribed burns can vary; this study was an opportunistic investigation. In one fortnight during autumn months of 2012, several prescribed burns were carried out in heathy-dry forests of central Victoria, Australia. We used measurements of canopy scorch, bark burn and ground cover burn to calculate a severity score for each site. The severity scores across sites ranged from low (2.5) to high (10). A before-after control-impact (BACI) design was utilised to model the potential impacts of fire and fire severity on birds. We used generalised linear mixed models (GLMM’s), and incorporated first- and second-year post-fire spring/summer observations from 2012 to 2014, against bird data from observations carried out in 2010. The total combined abundances of individual species showed that broadly, bird abundance rebounded to pre-burn levels by the second spring post-fire. There was little response detected in either species richness or turnover. The muted turnover result aligns to other studies that indicate a scarcity of early-successional-stage species in eucalyptus forests and woodlands that rapidly regenerate post-fire. Ten individual species were also examined, and only one species, the White-throated Treecreeper (Cormobates leucophaea), responded to both fire and its severity. The BACI design was informative in illustrating that while the forest birds were resilient to small-scale prescribed burns of any severity, abundances in general may have been in decline, a result aligning with the years of reduced rainfall in the region.

An observation of Sugar Gliders evicting nesting White-throated Treecreepers from a nest box in central Victoria

This note describes the eviction of nesting White-throated Treecreepers Cormobates leucophaea from a nest box by a Sugar Glider Petaurus breviceps in central Victoria. Predation of the birds and eggs was not observed.

Estimating the population sizes of rainforest birds of the Tweed Caldera

Climate change is likely to negatively impact populations of rainforest birds along Australia’s eastern seaboard. To this end, accurate estimations of species’ current population sizes are necessary for future monitoring and conservation. Here, we used distance sampling protocols to generate abundance and density estimates for 11 species of birds occupying the Gondwanan rainforests of the Tweed Caldera on the Queensland–New South Wales border. Data were collected along two elevational gradients in subtropical rainforest between September 2015 and October 2016. Half-normal functions with cosine adjustments were used to calculate the density of each species per km 2 . We used a GIS to determine the total area of suitable habitat available in protected areas adjacent to the sampling locations (~425 km 2 ) and then extrapolated the density estimates to generate estimates of population size for each target species in the study area. Estimated population sizes ranged from 473 719 (Yellow-throated Scrubwren Sericornis citreogularis ) to 21 841 (White-throated Treecreeper Cormobates leucophaea ). The standard error (SE) associated with the population estimate of the White-throated Treecreeper was large, as was the SE associated with the Eastern Yellow Robin Eopsaltria australis (estimated population 235 084), Green Catbird Ailuroedus crassirostris (69 731) and Grey Fantail Rhipidura fuliginosa (124 534). Accurate abundance estimates (SE <20% of total abundance) were obtained for the Brown Gerygone Gerygone mouki (193 919), Brown Thornbill Acanthiza pusilla (198 801), Golden Whistler Pachycephala pectoralis (72 730), Lewin’s Honeyeater Meliphaga lewinii (190 389), Silvereye Zosterops lateralis (92 268), White-browed Scrubwren Sericornis frontalis (94 426) and Yellow throated Scrubwren (473 719). Species specific surveys would provide more accurate results, but given the declines expected for many species in the region, and the current lack of estimates of population sizes in these protected areas, the baseline data presented here are of importance from ecological and conservation perspectives.

Artificial tree hollow creation for cavity-using wildlife – Trialling an alternative method to that of nest boxes

Tree hollow scarcity is a threat to cavity-dependent vertebrate wildlife world-wide across many landscapes. Currently, only nest boxes are commonly used to mitigate or offset lost cavity-bearing trees, with a number of shortfalls reported using this technique. There is a need to trial alternative techniques to improve artificial cavity provisions. This preliminary study investigated the use of carving hollows directly into tree trunks using chainsaws. Sixteen hollows of two simple cavity types were created in a timber production forest in south-eastern Australia. One cavity type comprised a basal entrance (38 mm in diameter) which provided a space above the entrance, intended for bats, and the other cavity type provided a space below a 38 mm or 76 mm entrance, intended for marsupials and birds. Five species used the hollows over a 15-month cavity monitoring period; feathertail glider (Acrobates pygmaeus) (in 75% of the hollows), brown antechinus (Antechinus stuartii) (75%), sugar glider (Petaurus breviceps) (63%), long-eared bat (Nyctophilus sp.) (50%) and white-throated treecreeper (Cormobates leucophaea) (25%). Camera monitoring revealed hollow inspection after only one day post hollow creation by white-throated treecreepers and feathertail gliders, and nest building by white-throated treecreepers after three days. No hollow host tree failure occurred for either of the two hollow wall widths trialled over two years of monitoring tree stability. Wound-wood formed and partly enclosed the hollows’ faceplates over time, improving the sturdiness of the hollow and likely resulted in hollows closely resembling natural cavities. Mechanically created tree hollows have a broad application potential across many landscapes with the prospect to overcome some of the reported drawbacks of nest boxes. More research is required to document long-term performance and effectiveness of this technique.

White-throated Treecreeper Cormobates leucophaea feeding on bracket fungus

White-throated Treecreepers Cormobates leucophaea are generally considered strict insectivores. This paper provides observational data of a female Treecreeper during winter feeding on a White Punk Laetiporus portentosus bracket fungus occurring in Victorian heathy dry forest.

Changes in bird assemblages during succession following disturbance in secondary wet forests in south-eastern Australia

After a successional forest is severely disturbed by wildfire and subsequent salvage logging or by clearfell timber harvesting and slash burning, if conditions are suitable, the forest will regenerate. It then passes through a series of stages of varying floristic composition and structure until further severe disturbance occurs. The characteristics of a forest-bird assemblage vary with both the successional stage of the forest (time period since the most recent severe disturbance event) and the long-term disturbance history of the forest. To determine how the bird assemblage changes during succession in a south-eastern Australian forest type that is fire-sensitive and also subject to regular timber harvesting, we surveyed birds in five age-classes of wet forest (from 2 to >100 years post-disturbance). Bird-assemblage composition altered sequentially; the pattern and rate of change reflected those of the vegetation. Bird abundance and species richness varied little during succession. No species of bird was abundant only in early successional forest. Some species, such as Brown Thornbill (Acanthiza pusilla), Golden Whistler (Pachycephala pectoralis) and Grey Fantail (Rhipidura albiscapa), were common in all successional stages. Other species, such as White-throated Treecreeper (Cormobates leucophaea) and Striated Pardalote (Pardalotus striatus), were consistently abundant in mid-to late successional stages only; this highlighted the importance of older forests for avian biodiversity. Any increase in the frequency of severe disturbance in these forests would tend to favour only those bird species that are already common. This has implications for management programs in forests that are habitat for wildlife, but are also used by humans for timber harvesting and other commercial or recreational purposes.

Dispersal behaviour of Brown Treecreepers predicts functional connectivity for several other woodland birds

The persistence of native species in fragmented landscapes is dependent on dispersal or foraging movements between habitat patches, which may be limited. Although corridors have been heralded as solutions, their effectiveness depends on species’ movement behaviour, which has rarely been studied. We previously analysed dispersal movements of Brown Treecreepers (Climacteris picumnus), concluding that scattered trees may provide greater connectivity than corridors, and the length of corridors and size of any gaps within may be more important than corridor width. However, conclusions from a single species may not be representative. Here, we analyse dispersal movements of two sedentary birds—Eastern Yellow Robins (Eopsaltria australis) and White-throated Treecreepers (Cormobates leucophaeus)—and foraging movements of two semi-nomadic birds—Fuscous Honeyeaters (Lichenostomus fuscus) and White-plumed Honeyeaters (L. penicillatus). Despite differences in their ecologies and purpose of movements, we found the movement strategies of these species at the local landscape scale were similar. The types of connectivity used and gap distances crossed were similar to those for Brown Treecreepers, strengthening our understanding of how to provide connectivity. We suggest that decision rules for movement have been shaped over evolutionary time by variability in the landscape, so movement behaviour may be less species-specific than previously assumed.

The response of ground and bark foraging insectivorous birds across an urban–forest gradient

This paper assesses the response of four common species of forest dependant insectivorous birds to an urban–forest gradient. The presence or absence was recorded for each species in landscapes that varied in landscape and site level attributes. Landscapes were classified into three categories based on their level of urbanisation. Broad comparisons across the landscapes were used to determine species specific response to increasing levels of urbanisation. Site level attributes were modelled to predict the patch occupancy for each species in each of the landscape types. Two broad trends were identified: the superb fairy wren ( Malurus cyaneus) and white-browed scrubwren ( Sericornis frontalis) displayed a tolerance to urbanisation and the eastern yellow robin ( Eosaltrica australis) and white throated treecreeper ( Cormobates leucophaeus) demonstrated a threshold response to urbanisation. The density of roads (−ve) and the extent of tree cover (+ve) in a landscape were highly correlated with the occurrence of urban sensitive species while at the site level the density of roads and density of rivers were the strongest contributors to their presence. The marked differences in the isolation and connectivity of patches where the threshold for urban sensitive species ceases are the likely contributors to their decline and sensitivity to suburban habitats. Conservation and management of urban sensitive species is largely dependant on the way urban development is managed. Of critical importance is careful planning in urban-fringe environments.

Gap‐crossing decisions of forest birds in a fragmented landscape

AbstractHabitat loss and fragmentation are recognized as primary drivers of biodiversity loss worldwide. To understand the functional effects of habitat fragmentation on bird populations, data on movement across gaps in habitat cover are necessary, although rarely available. In this study, we used call playback to simulate a conspecific territorial intruder to entice birds to move through the landscape in a predictable and directional manner. We then quantified the probability of movement in continuous forest and across cleared gaps for two forest‐dependent species, the grey shrike‐thrush (Colluricincla harmonica) and the white‐throated treecreeper (Cormobates leucophaeus). Fifty‐four playback trials were conducted for each species across distances ranging from 25 to 480 m in continuous forest and 15–260 m across gaps in a forest‐agricultural landscape in southern Victoria, Australia. The probability of movement was significantly reduced by gaps in forest cover for both species. Shrike‐thrushes were six times more likely to move 170 m in continuous forest than to cross 170‐m gaps. The mean probability that treecreepers would cross any gap at all was less than 0.5, and they were three times less likely to move 50 m across a gap than through continuous forest. Both species displayed non‐linear responses to increasing gap distance: we identified a gap‐tolerance threshold of 85 m for the shrike‐thrush and 65 m for the treecreeper beyond which individuals were most unlikely to cross. The presence of scattered paddock trees increased functional connectivity for the shrike‐thrush, with individuals crossing up to 260 m when scattered trees were present. We conclude that gaps in habitat cover are barriers to movement, and that characteristics of the intervening matrix influence landscape permeability.

A study of the foraging ecology of the White-throated Treecreeper (Cormobates leucophaeus)

We quantified the foraging ecology of the White-throated Treecreeper (Cormobates leucophaeus) in the Australian Capital Territory (ACT), south-eastern Australia, where it is the sole species of treecreeper present, and where a rough-barked eucalypt (Red Stringybark (Eucalyptus macrorhyncha)) and a smooth-barked eucalypt (Inland Scribbly Gum (Eucalyptus rossii)) are the dominant tree species. We examined relationships among foraging observations and variables including tree species, tree size, part of tree (substrate), time of day and month. We also quantified the kinds of foraging techniques used by the White-throated Treecreeper on different type and sizes of trees and at different times of the year. The White-throated Treecreeper more commonly foraged on Red Stringybark than on Inland Scribbly Gum. On Red Stringybark, the birds foraged more frequently on the trunk (above 4 m) and large branches than on other substrates. This trend was less marked on Inland Scribbly Gum, where dead branches were most often used for foraging. Foraging techniques that allowed rapid searching of each tree were those employed most commonly. Of these techniques, gleaning was most common (>50% of foraging time), but peering also was common. Drilling was most commonly performed on dead substrates. Foraging techniques employed by the White-throated Treecreeper changed significantly from morning to afternoon, with an increase in peering in afternoons. An increase in peering was observed for both sexes in April, but the magnitude of the increase was greater for females. White-throated Treecreepers in the ACT foraged more commonly on rough-barked eucalypts and exhibited less intraspecific resource partitioning between sexes than reported from other regions. Some of these differences may be related to contrasts in bird assemblages, particularly the absence of other bark-foraging species which may, in turn, reduce levels of intraspecific (gender-based) competition and resource partitioning. They also may be associated with differences in habitat attributes and resource availability between study areas.

Comparative demography of treecreepers: evaluating hypotheses for the evolution and maintenance of cooperative breeding

Despite the long history of research on cooperative breeding, few comparative studies have been undertaken to test hypotheses for the evolution and maintenance of delayed dispersal using data from both cooperative and noncooperative species. We tested predictions about demographic differences between cooperative and noncooperative species based on four hypotheses for the evolution of delayed dispersal: the ecological constraints hypothesis, the life history hypothesis, the broad constraints hypothesis and the benefits-of-philopatry hypothesis. We controlled for phylogeny and habitat by comparing sympatric populations of two Australasian treecreepers (Climacteridae): the cooperatively breeding brown treecreeper, Climacteris picumnus, and the pair-breeding white-throated treecreeper, Cormobates leucophaea, which has lost cooperative breeding despite phylogenetic conservation of the trait in most of the treecreeper lineage. Our data failed to support nearly every prediction of the constraints and life history hypotheses. The two species had similar levels of constraints and similar life histories, and any significant differences were in the opposite direction to those predicted. However, the cooperative species was characterized by significantly higher variance in reproductive success as a result of group size effects, supporting the benefits-of-philopatry hypothesis as an explanation for the maintenance of delayed dispersal. Our comparisons also suggest that the benefits parents derive from group living determine whether or not they tolerate offspring on the natal territory. We therefore propose an antipredator tactics hypothesis in which delayed dispersal will initially evolve or be lost in particular taxa depending on the relative costs and benefits of vigilance and active defence versus concealment-based antipredator tactics.

Habitat selection in two Australasian treecreepers: what cues should they use?

When habitats differ in quality, individuals may attempt to maximise fitness through habitat selection. However, complete tests of habitat selection are rare, in part because many studies fail to quantify fitness consequences of habitat choice. We studied habitat selection of Australasian treecreepers (Passeriformes: Climacteridae) in temperate eucalypt woodland by examining the influence of habitat characteristics and confounding factors on annual reproductive success. In the pair-breeding White-throated Treecreeper (Cormobates leucophaeus), older females and territories with fewer stumps and less woody debris produced more young, possibly because these habitat characteristics lead to reduced conflict with Brown Treecreepers (Climacteris picumnus). In the cooperatively breeding Brown Treecreeper, larger groups and territories with lower densities of shrub, moderate levels of ground cover, and greater amounts of foraging substrate produced more fledglings, whereas territories with greater invertebrate biomass produced more independent young. Predicted annual reproductive success in the best territory was up to two offspring more than predicted success in the worst territory; thus, treecreepers would benefit from selecting good quality habitat. However, complete tests of habitat selection need to evaluate whether dispersers actively sample multiple habitats and choose the best available, and thus whether individual-level processes determine large-scale patterns of distribution and abundance. These results also suggest that current conservation efforts to exclude grazing from remnant patches of eucalypt woodland may be inappropriate if not used in conjunction with other management actions, because such exclusion may dramatically increase shrub density and ground cover. Alternative management tools need to be investigated that will maintain a mosaic of microhabitat types and thus protect the eucalypt woodland ecosystem, not just a few of its species.

Characterization of microsatellite loci in the brown treecreeper (Climacteris picumnus) and cross‐species amplification in the white‐throated treecreeper (Cormobates leucophaeus)

AbstractEight polymorphic microsatellite markers were developed for the brown treecreeper, Climacteris picumnus. The number of alleles ranged from three to 25 per locus with observed heterozygosities between 0.05 and 0.76. Seven of the eight primer pairs also amplified polymorphic microsatellite loci in the white‐throated treecreeper (Cormobates leucophaeus). These markers are likely to be useful for population genetic and parentage studies in any of the Australasian treecreepers (Climacteridae) and are the first genetic markers developed for any member of this passerine family.

Edge effects on the distribution and abundance of birds in a southern Victorian forest

An important consequence of habitat fragmentation for wildlife communities is the effect of an increase in the ratio of habitat edge to interior. This study compares the bird communities at forest/farmland edges and in forest interior at Bunyip State Park, Victoria. Overall, there was a significantly higher number of bird species and individuals in forest edge than in forest interior sites. The greater diversity of species at edge sites appeared to be due to an increase in forest-edge specialists, as opposed to an influx of open-country species. Four bird species: the white-throated treecreeper (Cormobates leucophaeus), the superb fairy-wren (Malurus cyaneus), the grey shrike-thrush (Colluricincla harmonica) and the grey fantail (Rhipidura fuliginosa) were significantly more abundant in edge sites. There were no species that were significantly more abundant in interior sites. Differences between the bird communities in edge and interior sites were attributed to increased foraging opportunities in the open country adjacent to forest edges.

TESTING SPATIAL PVA MODELS OF AUSTRALIAN TREECREEPERS (AVES: CLIMACTERIDAE) IN FRAGMENTED FOREST

Population viability analysis (PVA) and other stochastic population models are frequently built and often used, but rarely tested. Stochastic metapopulation models of the White-throated Treecreeper (Cormobates leucophaea) and the Red-browed Treecreeper (Climacteris erythrops) were developed in a system of 39 remnant patches of eucalypt forest in southeastern New South Wales, Australia. Parameters of the model were estimated using data obtained outside the fragmented system. Field surveys of the patches were conducted to test the predicted probabilities of patch occupancy, which is one of few instances where stochastic population models have been tested with empirical data. The initial models underestimated the occupancy of the patches, and the models were modified using the results of the tests in conjunction with further information on the biology of the species. A number of different modifications were made to determine changes that produced results that matched the observations. The best of these modifications made reasonable predictions, although this is not equivalent to a test with independent data because the data were known prior to the modifications. The best-fitting modified models were tested by comparing the observed number of extinction and colonization events to the predicted number. The models underestimated the observed number of events, although imperfect survey methods may have contributed to these differences. The tests of the stochastic models contributed to their development by highlighting the nature of the predictive error. The modified models predicted that the White-throated Treecreeper would be likely to persist over the next 100 years in most of the 39 patches. In contrast, the Red-browed Treecreeper was predicted to become extinct in most patches within about 50 years of fragmentation. This study illustrates how spatial patterns can be used to test the predictions of population dynamic models, although we note that the tests are limited by survey error and spatial correlation in occupancy data.

Summer Field Metabolic Rate and Water Intake Rate in Superb Fairy-wrens and a White-throated Treecreeper

(1997). Summer Field Metabolic Rate and Water Intake Rate in Superb Fairy-wrens and a White-throated Treecreeper. Emu - Austral Ornithology: Vol. 97, No. 4, pp. 324-325.

Changes in populations of bird species in roadside softwood scrub remnants/farmland and open eucalypt forest in south-east Queensland, 1981 to 1993

Long-term monitoring of bird species provides information on base-line populations and population trends required to ensure that habitat management is effective for their conservation. Two surveys in both spring and autumn over 12 years monitored populations at fixed points in roadside softwood scrub remnants plus adjoining farmland (softwood/farmland) and in eucalypt open forest in south-east Queensland. The main aims were to determine the status of species in each habitat, especially whether the status of any species was changing, and to assess the usefulness of the monitoring procedure. In all, 92 species were observed; 79 in the softwood/farmland and 74 in the eucalypt forest. From 49 to 56 species were observed each year in softwood/farmland and 34 to 46 in eucalypt forest. Annual species turnover in softwood/farmland was about half that in eucalypt forest; 39% of all species were observed every year in the former habitat, but only 19% in the latter. The Torresian Crow was most often observed in softwood/farmland and the Noisy Miner in eucalypt forest. The Torresian Crow was the only species to be among the five most observed in each habitat. Among other common species, 95% or more observations of Bar-shouldered Doves, Superb Fairy-wrens, Yellow Thornbills and Silvereyes were in softwood/farmland, whereas for Weebills, White-throated Gerygones, Buff-rumped Thornbills, White-throated Treecreepers and White-throated Honeyeaters at least 95% of observations were in eucalypt forest, confirming their strong habitat specificities. The number of birds observed increased linearly for eight species in softwood/farmland and six species in eucalypt forest, and decreased for five and four species, respectively, over the 12 years. The most significant trends were for the Crested Pigeon (increase) and Willie Wagtail (decrease) in softwood/farmland, while Peaceful Dove and Rufous Whistler decreased in both habitats. Several species which increased adapt well to partial clearing of woody vegetation and aggressively exclude others, e.g., Noisy Miner, butcherbirds and Pied Currawong. The trends may reflect insidious degradation of habitats. The main value of the survey method was for detecting changes of species that could be used as indicator species ? those that respond most rapidly to habitat change. While the method was efficient, wildlife managers would need to use it regularly to maintain skills, especially because most observations are of bird calls.

A Demographic Comparison of Cooperatively Breeding and Non-Cooperative Treecreepers (Climacteridae)

SummaryColour-banded populations of White-throated Cormobates leucophaea, Red-browed Climacteris erythrops and Brown Treecreepers CI. picumnus were studied for up to six years in north-eastern New South Wales. All species are sexually dimorphic, insectivorous and nest in tree-holes. The White-throated and Red-browed are totally arboreal and nearly identical in size while the Brown spends half of its time on the ground and is about 50% larger than the other two species. The non-cooperative White-throated held small individual or pair territories which were vigorously defended but not stable over the study period. Offspring were evicted from the natal territory when independent and very few were seen again on the study sites. Cooperatively breeding Red-browed and Brown Treecreepers lived in pairs or groups which contained one breeding bird of each sex and up to three helpers. About one-quarter of the offspring of both species stayed on the study site for one year or more, and almost all were males. Helpers participated in nest construction, feeding of the incubating female, and feeding and defence of the young. Territories were larger, more static and less regularly defended than in the White-throated. Breeding success of the White-throated did not differ significantly from that of the Red-browed or Brown. However, within the latter two species, groups produced more young than pairs. Adult survivorship was higher in the Brown than in the White-throated where they co-existed. Survivorship of coexisting Red-browed and White-throated was similar, until the onset of a drought which had a greater negative effect on the latter. Group-living and cooperative breeding are probably related to specialised niche requirements and lack of suitable habitat in the patchily-distributed Red-browed, while in the widespread and semi-terrestrial Brown, predation appears to have played the major role. Roost-holes may be a limited resource for both cooperatively breeding species, favouring philopatry.

Notes on the White-throated Treecreeper

Notes on the White-throated Treecreeper