Pied Currawong Strepera Graculina Research Articles

Predation of Eastern Yellow Robin nestlings from the same nest by an Eastern Ringtail Possum and a Pied Currawong

This note describes the predation of nestling Eastern Yellow Robins Eopsaltria australis by an Eastern Ringtail Possum Pseudocheirus peregrinus and by a Pied Currawong Strepera graculina and likely attempted predation by a Red Wattlebird Anthochaera carunculata. Although Eastern Ringtail Possums have been inferred to be predators of birds’ nests, the observations and video presented here appear to be the first unequivocal evidence of carnivory in that species and offer new insights to this possum species’ ecology.

Interacting impacts of drought and fire on bird populations—insights from a long-term study in the Warrumbungles

ABSTRACT The interacting effects of drought and fire on ecological communities are poorly understood. Long-term studies in the Warrumbungle Mountains, central-west New South Wales, subject to drought and fire during the past 21 years, enabled their separate and combined effects to be quantified for individual species and functional groups. Insectivores (especially ground-foragers) dominated previous lists of declining species in this region of NSW and were also prominent in the present work. Insectivores were more likely to be drought- than fire-affected, with seven species declining due to drought, three to drought plus fire, and three to fire alone. Our analyses also revealed declines in a suite of honeyeaters (Meliphagidae), previously not reported as declining. Honeyeaters are major pollinators of eucalypts, so the loss of nectarivores and insectivores has far-reaching implications for pollination, recruitment, successional dynamics, and forest health. Four honeyeater species were adversely affected by drought, five by fire, and one by a combination of drought and fire. Drought and fire, alone or in combination, were implicated in declines of granivores, including the Crimson Rosella Platycercus elegans, and frugivores, especially the Mistletoebird Dicaeum hirundinaceum, the latter reflecting the loss of mistletoes in fire-affected landscapes, and foreshadowing additional losses due to the reliance on mistletoe by many species. Another group not previously identified as threatened, but declining due to drought were two omnivores, the Pied Currawong Strepera graculina and Australian Raven Corvus coronoides. Hollow-nesting birds including two species of treecreeper and the Laughing Kookaburra Dacelo novaeguineae fared badly. Several common Australian species were among the decliners, including Laughing Kookaburra, Willie Wagtail Rhipidura leucophrys and Australian Magpie Cracticus tibicen. We conclude that no suite of birds is exempt from these environmental stressors, and predict that, as droughts reduce populations at regional scales and fires diminish carrying capacity of critical habitats at landscape scales, rarer species will decline to local extinction while more commonly observed species will be reduced in abundance.

Consumption of Canary Island Date Palm Phoenix canariensis drupes by Pied Currawongs Strepera graculina

In Australia, Canary Island Date Palms Phoenix canariensis are ubiquitous, widely planted as ornamental trees in private gardens and along streets and seaside promenades. Seeding freely, a single female palm can produce up to 30,000 fleshy drupes annually. Pied Currawongs Strepera graculina, which can swallow several drupes whole in a single feeding event, present as a major vector in the plant’s dispersal. Based on observations of feeding behaviour as well as an examination of resulting regurgitated pellets, this paper discusses critical factors that influence the performance of Pied Currawongs as a vector of palms. Pied Currawongs exhibit drupe selection preferences, which seem related to a drupe’s ripeness and nutritional value, and a feeding behaviour that consists of short bouts of consumption, followed by longer periods of digestion at nearby perches. As increased ripening of the fruit correlates with an increased maturation of the seed, resulting in a higher germination rate, and as repeated use of nearby perches increases the density of regurgitated seeds, such behaviour has implications on the effectiveness of Pied Currawongs as dispersers of Canary Island Date Palms.

Meta‐analyses of nest predation in temperate Australian forests and woodlands

AbstractNest predation is the leading cause of nesting failure. Thus it is a crucial area of research needed to inform conservation management and to understand the life history of birds. I surveyed the literature to review the identity of nest predators and the factors affecting nest predation, in Australia using 177 studies. Overall, 94 nest predators were identified when incorporating artificial nests, 69 without. Using only natural nests, the Pied Currawong Strepera graculina was the most frequently reported nest predator. Five nest predators, including Pied Currawong, depredated 40% of the prey measured by the number of prey species taken. Yet, 60% of predation was carried out by the other 64 species, which included by the order of importance birds, mammals, reptiles, frogs and ants. Predation at cup and dome nests was more frequently reported than at burrow, ground and hollow nests. Only 28% of predators were observed at both artificial and natural nests suggesting artificial nests have limited, but not negligible, ability as tools for identifying predators. There was a highly significant and positive correlation between predator and prey masses. The predator prey mass ratio was calculated with a mean 0.25 and a median 0.22, a result closely matching with the proportional size of prey taken by raptors. The finding that predator size is proportional to prey opens a pathway for more life history and conservation research.

Pied Currawong Strepera graculina nesting in an underground carpark

A pair of Pied Currawongs Strepera graculina was observed nesting in an underground carpark of a suburban shopping centre in Brisbane, Queensland. Previous years’ nests, presumed to be from this species, were detected, indicating that these birds had probably been doing this for at least 3 years. Such plasticity in nest placement suggests that this species is continuing to adjust to urban environs, which might lead to increasing its already significant nest-predatory impact on other birds.

Taxonomic and nomenclatural implications of a review of the Pied Currawong Strepera graculina in southern Victoria

In a review of knowledge about subspecies of the Pied Currawong in southern Victoria and far south-eastern South Australia, Menkhorst & Morley (2017) hypothesised that the type specimen of Strepera graculina ashbyi Mathews 1913 might be an immature female of the population currently recognized as S. g. nebulosa Schodde and Mason 1999. If this hypothesis is correct, there are nomenclatural consequences, which we detail here. We also retract the suggestion that neotypes should be defined for the subspecies concerned.

Observations of mobbing and other agonistic responses to the Powerful Owl Ninox strenua

Mobbing is an anti-predator strategy in which prey animals, notably birds and mammals, aggravate a potential predator to either distract or drive them from the vicinity. The Powerful Owl Ninox strenua is a large forest owl endemic to eastern Australia that preys mainly on arboreal mammals and birds. We identified records of 30 species of birds and one mammal known to mob the Powerful Owl from scientific literature and unpublished studies. In our study in southern Sydney, Powerful Owls were most frequently mobbed by Noisy Miners Manorina melanocephala and Pied Currawongs Strepera graculina, followed by Grey Butcherbirds Cracticus torquatus and Australian Magpies Cracticus tibicen. We observed mobbing by three species of bird and one mammal that were not previously recorded as mobbing species, including agonistic responses by a Tawny Frogmouth Podargus strigoides and Common Brushtail Possum Trichosurus vulpecula during the time owls were active.

The conflict between animal welfare and conservation

IT is a measure of a civilized society that its inhabitants are concerned about the welfare of animals. Furthermore, there has been increasing concern about conservation, especially of threatened species. In many countries, including Australia, there is now extensive legislation to cover both animal welfare and the protection of many native species. Whereas welfare deals with individuals, conservation is concerned with populations. Thus, researchers must always weigh potential gains in knowledge against the consequences of their activities (see Gaunt and Oring 1997). Ironically, management for conservation often involves the killing of individuals of one species, typically predators or competitors, for the good of the population of another species. In Australia many of the animals that are killed are feral (e.g., foxes and rabbits). As some feral species also have major impacts on agriculture, the need to control their numbers is generally accepted and attracts little attention. However, there is mounting evidence that a number of native species may pose threats to declining or endangered native species. For instance, Pied Currawongs Strepera graculina are known to be nest predators and Noisy Miners Manorina rnelanocephala are known to drive most other small birds from the vicinity of their colonies. Many woodlarid birds are experiencing long-term decline and it has been hypothesized that Pied Currawongs and Noisy Miners contribute to this decline (Ford et al. 2001). We set out to test experimentally the hypothesis that Pied Currawongs are major nest predators.

The Pied Currawong's role in avian nest predation: a predator removal experiment

Pied Currawongs Strepera graculina have been implicated as a major threat to the persistence of small passerines in urban and rural landscapes through their intense nest predation while raising their young. Pied Currawongs have recently increased in abundance and colonized new areas, due to the planting of exotic berry-bearing trees and shrubs. In association with habitat fragmentation, this may have intensified their predatory impact. We measured the rate of predation on 416 artificial nests, using quail and plasticine eggs, in a 240 ha remnant of eucalypt woodland. Nests were placed in one grid from which Pied Currawongs were removed and in one control grid. The level of predation was monitored before and after Pied Currawong removal. Overall, nest predation was extremely high with 91 % of all nests preyed upon in seven days. Moreover, nest predation decreased significantly following Pied Currawong removal, thus identifying them as significant nest predators. However, imprint evidence from plasticine eggs and the remains of real eggs indicate that other animals, particularly other birds, are also important predators. If this high level of nest predation is reflected in real nests and occurs over a number of years, it may lead to low recruitment of open-nesting birds at this site. If it occurs regionally, it could contribute to long term declines of these species. Our findings suggest that even quite large woodland fragments may be too small to sustain many declining bird species.

Seasonal Changes in Diet of Pied Currawongs Strepera graculina at Wollongong, New South Wales

SummaryData on the diet of Pied Currawongs Strepera graculina were acquired from incidental records from 1984–96 and 165 hours of observation at four nests. In the non-breeding season, fruit from native and introduced trees was the major component of diet. In the breeding season, breeding currawongs switched to a diet consisting mostly of insects (91% by weight) before eggs were hatched and mostly of nestling and juvenile birds (55% by weight) when feeding their own nestlings. Estimated food consumption rates were 0.56 g per currawong-hour (parents only) for insect prey in the incubation period and 0.67 g per currawong-hour (parents and nestlings) for passerine prey in the nestling period. During a breeding episode, a breeding pair of currawongs may capture up to 2000 g of young passerines. The method of dismembering prey is described.

Conservation of the endangered Gould's Petrel Pterodroma leucoptera leucoptera

The only population of Gould's Petrel Pterodroma leucoptera leucoptera has declined substantially during the last few decades. Adult mortality has been high, and has exceeded potential recruitment. Breeding success has been low. Entanglement in the sticky fruits of the Birdlime Tree Pisonia umbellifera and predation by Pied Currawongs Strepera graculina and Australian Ravens Corvus coronoides have been the major causes of petrel mortality on land. Experimental management actions aimed at ameliorating these threats were implemented, and their efficacy assessed. The removal of Pisonia and the control of avian predators dramatically lessened the mortality of Gould's Petrels ashore on Cabbage Tree Island. Instigation of these management actions in 1993 was coincident with a 68% rise in the number of birds brooding eggs in mid-December. Further small increases in the breeding population occurred in subsequent years. Management of the colony was also coincident with a substantial increase in breeding success (up from 25% to 45%). Breeding success increased to 59% in the 1994?95 season, but declined to 26% during 1995?96. Prior to management of the colony, an average of 30 birds fledged per annum (range 23?40; n= 4); after management, this rose to 167 per annum (range 105?233; n= 3). Management of the colony appears the most likely cause of this turnaround, but the possibility of it being due to extraneous factors such as weather or oceanographic perturbations cannot be excluded. The threats posed by Pisonia umbellifera and avian predators were, together, sufficient to account for the decline of Gould's Petrel. The demonstration that these two threatening processes can be ameliorated successfully suggests a high potential for recovery of the species.

Mortality of Adult Gould's Petrels Pterodroma leucoptera leucoptera at the Nesting Site on Cabbage Tree Island, New South Wales

The remains of adult Gould's Petrels Pterodroma leucoptera leucoptera were recovered from the nesting site on Cabbage Tree Island, New South Wales. Entanglement in the sticky fruits of the Bird-lime Tree Pisonia urnbellifera was identified as a major cause of mortality. Removal of P. urnbellifera eliminated one cause of death but mortality of adult petrels continued at an unsustainable rate as the result of predation by the Pied Currawong Strepera graculina. Hunting and feeding behaviour of the Pied Currawongs were observed, including holding fast a petrel carcass while ripping flesh from the skeleton. Mortality of Gould's Petrels subsided immediately following the destruction of Pied Currawong nests and nestlings. Subsequent recurrences of predation were correlated with additional nesting attempts by Pied Currawongs but declined substantially following the instigation of a control program for Pied Currawongs on Cabbage Tree Island. Pied Currawongs take the eggs and nestlings of many species of birds, but losses of nesting adults or the decline of a seabird have not been attributed previously to currawong predation.

NOTES ON THE TICK HAEMAPHYSALIS(ORNITHOPHYSALIS) DOENITZI WARBURTON AND NUTTALL (ACARINA: IXODIDAE) IN AUSTRALIA

AbstractDoenitz' Oriental‐Australian bird baemaphysalid, Haemaphysalis(O.) doenitzi has been recorded as a parasite of the swamp pheasant, Centropusphasianinus (Latham) at Yeppoon Queensland. In the laboratory larvae engorged on Rattus fuscipes (Waterhouse) but not on a marsupial bandicoot Isoodon macrourus (Gould). Nymphs did not engorge on a variety of host species [man, cattle, domestic fowl, and pied currawong Strepera graculina (Shaw)] but a small proportion fed on R. fuscipes and on a white mouse. Adults, nymphs and larvae from Australia are in agreement with the description of this tick from other parts of south east Asia. Larvae described as Haemaphysalis (Rhipistoma) bancrofti by Roberts (1969) are in fact larvae of H. (O.) doenitzi.