Noisy Miner Manorina Melanocephala Research Articles

Forecasting the impacts of habitat fragmentation. Evaluation of species-specific predictions of the impact of habitat fragmentation on birds in the box–ironbark forests of central Victoria, Australia

We tested forecasts made by Mac Nally and Bennett (Mac Nally, R., Bennett, A.F., 1997. Species-specific predictions of the impact of habitat fragmentation: local extinction of birds in the box-ironbark forests of central Victoria, Australia. Biological Conservation 82, 147–155) of relative vulnerability to habitat fragmentation for 43 species of birds in the box–ironbark system of central Victoria, Australia. The predictions were based on a simple, tripartite model linking habitat specialization, density and mobility, three of the characteristics most widely mooted in the literature to influence vulnerability to habitat fragmentation. For each species, a predicted index of ‘proneness’ to local extinction was calculated by using prior, independent data. The model system consisted of existing fragments of 10, 20, 40 and 80 ha size-classes, with between 5 and 15 ‘replicates’ of each size-class. Replicated ‘reference-areas’ — mapped-out areas of these same size-classes set within large (>10 000 ha) remnant forests of the same general vegetation as the fragments — were surveyed also to provide ‘expectations’ of the likelihood of finding each species in a given size-class. Our results indicated that the simple model had virtually no predictive power: the index-values for proneness to local extinction were no help in forecasting whether a given species was over- or under-represented in a fragment of a given size based on the bird's occurrence in reference-areas of similar size. When the three components of the model were tested separately, measures of habitat specialization and mobility showed no relationship with the observed responses of birds to fragmentation, while for population density there was a significant relationship but in a direction contrary to that expected. Evaluation of assumptions underlying the test revealed two main factors that are likely to have affected the model's performance: (1) differences in anthropogenic impacts between fragments and reference-areas have resulted in differences in habitat quality, and (2) species interactions within fragments differ from those in reference-areas, a result of secondary effects arising from the altered spatial pattern of the habitat (e.g. the expansion of numbers and influence of ‘despotic’ species such as the noisy miner Manorina melanocephala). These two factors appear to be common to most fragmented systems and, therefore, need to be addressed in predictive models of species vulnerability. However, because the nature of anthropogenic impacts and the types of changes to species interactions in fragments differ between ecosystems, we conclude that it will be difficult to develop a model of species' vulnerability to fragmentation that has both strong predictive ability and wide generality among ecosystems.

The use by wildlife of paddock trees in farmland

Morning and dusk watches at live and dead trees were used to systematically investigate which species of vertebrates use paddock trees within farmland proposed for the establishment of Eucalyptus plantations in northern New South Wales. Tree-watches at 108 trees were stratified on farmland as isolated, in small patches, remnant vegetation and riparian strips plus in adjacent forest. Arboreal marsupials and bats emerged from hollows in 11% and 8% of trees, respectively. Only one colonial bat roost was observed, although the marsupials Trichosurus vulpecula and Petaurus breviceps were widespread in the landscape. Two threatened species of marsupials (Petaurus norfolcensis and Phascogale tapoatafa) were observed using paddock trees on flats or slopes outside of riparian strips. Among owls, only the Southern Boobook Ninox novaeseelandiae and Barn Owl Tyto alba were observed using tree hollows on farmland. For all hollow-dependent nocturnal fauna (marsupials, bats and owls), very large tree diameter best predicted occupation of a tree-hollow (especially if <800 m from the nearest forest). In addition to providing hollows, paddock trees were used for foraging. Morning surveys revealed 35 diurnal bird species on isolated trees, although most were generalists (e.g., Eastern Rosella Platycercus eximius, Noisy Miner Manorina melanocephala) that were also regular visitors to non-isolated trees in remnant vegetation. More forest-dependent and forest-associated bird species were recorded in forests and riparian strips than other tree categories, reinforcing the high conservation value of riparian strips in farmland. After dark, ultrasonic detectors recorded 21 species of bat (seven threatened species) flying in close proximity to paddock trees. Relatively high levels of activity were recorded at one study location for species rarely recorded in forests (e.g., Scoteanax rueppellii). Remnant Eucalyptus tereticornis and E. amplifolia were a significant source of blossom for nectarivores and they were also associated with high bat activity, possibly because they grow on fertile soil. Recommendations on tree retention guidelines are discussed.

The avifauna of severely fragmented, Buloke Allocasuarina luehmanni woodland in western Victoria, Australia

Buloke Allocasuarina luehmanni woodland is an endangered habitat type that was once widespread in southern Australia but now is restricted to a series of remnants, many of which are located in the Wimmera region of western Victoria. The bird communities inhabiting 27 remnants were sampled on transects of 1.0 ha at 6-week intervals over one year. Ninety-five species of birds were observed in Buloke woodlands, of which 66 species were recorded during transect counts. The total species richness, the richness of groups of birds based on their habitat use, and the composition of assemblages on transects, were examined in a series of analyses with respect to habitat type (which probably reflects "quality"), remnant area, shape, isolation and geographic location. There was little evidence for attributes of remnants significantly influencing species richness per transect, but the composition of avifaunal assemblages varied in relation to habitat type, size and geographic location. The Buloke woodlands supported a diverse assemblage, including numerous species believed to be experiencing a regional decline in southern Australia. The composition of the Buloke assemblage has similarities to those of dry eucalypt woodlands across the plains of central Victoria, but elements contributing to a distinctive avifauna include species associated with semi-arid and mallee environments, and a high frequency of occurrence of a group of small insectivores (thornbills, robins) that favour dry She-oak and Callitris woodlands. A likely reason for the rich representation of small insectivores in woodland stands, even in small degraded remnants grazed by stock, was the scarcity of the Noisy Miner Manorina melanocephala that are often common in eucalypt remnants and known to aggressively exclude other species. The results of this study add weight to the recommendation that protection and restoration of Buloke woodlands is a priority for conservation in the Wimmera bioregion of Victoria.

Haematological changes during development of the noisy miner: implications for oxygen transport

Changes in erythrocyte numbers and size, haematocrit and blood haemoglobin concentration in noisy miner (Manorina melanocephala) nestlings were documented from measurements taken on wild individuals during development. Haematocrit, whole-blood haemoglobin concentration and erythrocyte count increased during development by factors of 2.0, 2.4 and 3.5, respectively. The increases were continuous and occurred at fairly constant rates throughout development, but typical adult values were not attained at fledging. Mean erythrocyte volume and mean erythrocyte haemoglobin content decreased continuously during nestling development. The estimated 2.4-fold increase in oxygen carrying capacity of the blood during development stemmed primarily from the increase in erythrocyte numbers. The reduction in erythrocyte volume would be expected to enhance oxygen delivery by increasing oxygen-diffusion rates. This pattern of constant change in blood parameters resembled that reported for species with standard, rather than unusually slow, rates of nestling development. We suggest that it reflects the fact that noisy miner nestlings grow relatively rapidly, perhaps because it reduces the exposure of nestlings to predation.

Influence of the Noisy Miner Manorina melanocephala on avian diversity and abundance in remnant Grey Box woodland

The abundance of an aggressive Australian honeyeater, the Noisy Miner Manorina melanocephala, was reduced at four small (<8 ha) Grey Box Eucalyptus microcarpa woodland remnants by experimental removal. The diversity and abundance of small insectivorous and nectarivorous birds increased at three of the four sites (relative to matching control sites) over the twelve months following the removal of the Noisy Miners. The one exception occurred at a pair of sites where eucalypts began flowering at one site and finished at the other during the Noisy Miner removal period. These results, taken together with those from three earlier experiments where the abundance of Noisy Miners was reduced in Mugga Ironbark E. Sideroxylon woodland remnants, demonstrate that Noisy Miners affect avian diversity and abundance by aggressive exclusion of other species. In five out of seven experiments, Noisy Miners did not reinvade the small woodland remnants during the ensuing twelve months. When Noisy Miner abundance was reduced, increased populations of small insectivorous and nectarivorous birds used small degraded woodland remnants. Colonizing populations of small birds have the potential to reduce insect infestations and may assist in the recovery of dieback-affected woodland remnants. Research is continuing to test this hypothesis. Reducing the abundance of Noisy Miners in remnant eucalypt woodlands may also be a useful, short-term measure, which could assist in the recovery of threatened or endangered bird species.

An experimental study of the translocation of noisy miners Manorina melanocephala and difficulties associated with dispersal

The aims of this study were to determine whether translocated noisy miners Manorina melanocephala were assimilated readily into noisy miner populations resident at release sites and, secondly, whether the number of birds in a release group influenced the subsequent behaviour, movement patterns and fate of translocated individuals. Birds were released in duos ( n = 5) or in groups of six ( n = 5). One bird in each duo or group was fitted with a radio transmitter. Although most translocated birds survived at least a month following translocation, they were not assimilated readily into resident populations of miners, but instead wandered much further (mean maximum distance from release site = 4·2 km) than the average diameter of the species' home range (∼ 200 m). At least two of the 40 translocated birds returned to their capture site; a distance of 18 km. The distances travelled by radio-tagged birds from their release sites rendered invalid the assumption that one release group/duo did not influence how another group/duo behaved. The difficulties such widespread dispersal pose to attempts at experimental examination of factors influencing the success of translocations are discussed.

Mating system of the cooperatively breeding noisy miner Manorina melanocephala, as revealed by DNA profiling

Mating system of the cooperatively breeding noisy miner Manorina melanocephala, as revealed by DNA profiling

Mating system of the cooperatively breeding noisy miner Manorina melanocephala, as revealed by DNA profiling

In this study we examined parentage within broods of the cooperatively breeding noisy miner using multi-locus DNA profiling. Previous studies of noisy miners described them as highly promiscuous, leading to the suggestion that promiscuous mating behaviour was a tactic used by females to recruit males as provisioners to their nests (Dow 1978). At our study site in south-east Queensland, Australia, we found that both multiple and extra-group paternity (i.e. a female mating with a male outside the group of male provisioners at her nest) were rare. In nests where multiple paternity was possible (i.e. clutch size > 1) 97% of 31 broods were sired by only a single male. Overall, 96.5% of all nestlings (n = 85) were the result of monogamous matings. Also, at the vast majority of nests, the male that sired the nestlings was also the main provisioner among all male nest attendants. Our results show that the mating system of the noisy miner can no longer be considered cooperative polyandry (Brown 1987) but is clearly genetic monogamy. We discuss the implications of this finding for understanding the complex social system of this species.

The Vocal Repertoires of Six Honeyeater (Meliphagidae) Species from Adelaide, South Australia

Honeyeaters (Meliphagidae) are prominent members of the avifauna in Australia, typically with four to five resident species in any area. We recorded vocalisations from six species resident around Adelaide in South Australia: the Red Wattlebird Anthochaera carunculata, Little Wattlebird Anthochaera chrysoptera, Noisy Miner Manorina melanocephala, White-plumed Honeyeater Lichenostomus penicillatus, New Holland Honeyeater Phylidonyris novaehollandiae and Crescent Honeyeater Phylidonyris pyrrhoptera. The larger honeyeaters (Red and Little Wattlebird) produced characteristically harsh vocalisations covering a wide range of frequencies. Crescent and White-plumed Honeyeaters had a varied and complex repertoire of calls and songs which were quite musical in nature. Noisy Miners and New Holland Honeyeaters produced vocalisations dominated by simple single note whistles. Each species had specific vocalisations emitted in different contexts: alarm, distress, begging and contact calls as well as song. Alarm and distress calls of the six species had common characteristics and typically induced responses from other honeyeater species.

Indiscriminate Interspecific Aggression Leading to Almost Sole Occupancy of Space by a Single Species of Bird

SUMMARYDow, D. D. 1977. Indiscriminate interspecific aggression leading to almost sole occupancy of space by a single species of bird. Emu 77: 115–121.Noisy Miners Manorina melanocephala, Australian honeyeaters, reside and feed in dense colonies in open woodland all year. All other species entering these colonies are attacked, sometimes killed. M. melanocephala, through group aggression, successfully defends its colonies against intrusion and settlement by other species of birds. Comparison with scarcer populations in more structurally complex woodland, where the species is less able to eliminate others, suggests that the advantage gained by the interspecific aggression pertains to food resources, because the species forages more in a wider range of feeding zones in areas where possible competitors have been ousted. By eliminating virtually all competitors, M. melanocephala gains exclusive use of all food resources in its colonies. Such interspecific interaction is unique among birds and possibly among animals in general. Also, M. melanocephala breeds communally, i.e. many individuals feed the young in a single nest. Food items given to the young are usually very small and the number of feeding trips to the nest extremely high. This high rate of feeding may be necessitated by the relatively greater abundance of small insects, which in turn could be due to the complete absence of smaller avian competitors.