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Management of the Orange-bellied Parrot
... 269 The Orange-bellied Parrot, Neophema chrysogaster, is one of Australia's most threatened species and is listed as 'critical' by the IUCN (1994). The population size is below 200 (Loyn et al., 1986; Menkhorst et al., 1990; Starks et al., 1992; McCarthy, 1995). Birds breed during summer in coastal areas of south-western Tasmania (Brown and Wilson, 1982). ...
... Though the fecundity of the birds is high, the population size appears to be stable at low numbers. Therefore it is believed (Menkhorst et al., 1990) that high mortality during winter is responsible for the persistent small population size. There are two major objectives in the management of the Orange-bellied Parrot: to increase the (mean) population size and to reduce the risk of population decline. ...
... We quantify the latter by the quasiextinction risk which is defined as the probability that the population size falls below a particular threshold within a particular time horizon (Ginzburg et al., 1982). Management options exist for both breeding and wintering sites (Menkhorst et al., 1990; Stephenson, 1991). In the breeding habitat they include fire management, artificial feeding and the provision of nest boxes. ...
The population dynamics of a rare and dispersed species like the Orange-bellied Parrot Neophema chrysogaster include many uncertainties, especially concerning mortality. Taking these uncertainties into account we evaluated several options for management of the Orange-bellied Parrot habitat. Options were ranked by their effects on the viability of the population. There was considerable variability in the resulting rank orders. A few general features appeared to be rather stable with respect to all forms of uncertainty considered. It was found that survival of birds during the winter season was more important than their reproductive success in summer and qualitative features of the habitat, such as the composition of vegetation, were more important than quantitative features such as the habitat size.
... Here, because of the close proximity of habitat to concentrated urban areas, there have been repeated threats from development over the years. In the Port Phillip Bay arear these have included expansion of the Avalon Airfield and construction of a new port at Point Lillias (Brown and Wilson, 1984;Menkhorst, Loyn andBrown, 1990, Edgar andMenkhorst, 1993). ...
... Early studies by Brown and Wilson (1980, 1981, 1982 and the recovery plan that resulted from these studies (Brown and Wilson 1984) concentrated mostly on locating the species and conserving habitat through reservation and land-use management. During this period, population estimates and trends were based predominantly on counts of birds occupying key wintering habitats in Victoria and South Australia (Menkhorst et al. 1990). Since 1987, a colour-banding program has been undertaken and accompanied by intensive resighting effort to provide information on survivorship and other demographic parameters. ...
Knowledge of demographic parameters, including survival, are fundamental to understanding the population dynamics of any taxon. Here we report on a long-term capture–mark–recapture study of the Orange-bellied Parrot (Neophema chrysogaster), one of the world’s most threatened parrots, using capture histories of 848 known-age wild birds. Parameter estimates of survival and probability of recapture were derived using the program MARK 4.1. Mean annual survival of juveniles and adults was estimated at 0.56 (s.e. 0.07) and 0.65 (s.e. 0.14) respectively. There was no evidence for an effect of sex on survival. Survival of three age-classes was estimated at 0.53 (s.e. 0.08) for juveniles, 0.64 (s.e. 0.11) for first-year birds and 0.59 (s.e. 0.09) for adults (2 years and older), indicating that maximum survival occurs in the second year of life, and declines thereafter. Although survival for both adults and juveniles varied considerably across years, there was no evidence of a decline in survival over the 20 years of the study. However, there has been an annual decline in the numbers of adult birds observed each year at the breeding grounds of 12% between 2000 and 2008, current survival rates do not appear to be a factor inhibiting population growth. The observed decline is more likely to result from a decline in female participation in breeding resulting in a decrease in the recruitment of juveniles to the population.
... Consider an illustrative example from Australia. Due to industrial development in the coastal regions of south-eastern Australia, wintering habitat of the Orange-bellied Parrot (Neophema chrysogaster) was heavily reduced and brought the population size down to a critically low number of around 150 individuals (Menkhorst et al. 1990). At this size the population is subject to various risks including genetic inbreeding, storm casualties and predation. ...
Ecologists usually argue for a proactive approach to species conservation—it should start before a species is endangered and
under substantial risk of extinction. In reality, however, conservation often only starts when species populations are already
in a critical state. This may be the result of a policy process in which those actors who see only little or no benefits from
conserving species try to delay conservation as long as possible to avoid its cost. A frequent consequence is that populations
decline to critical levels so that once conservation policies set in due to legal obligations, political pressure or any other
reason, additional conservation measures are required to re-establish the populations. We show that the costs associated with
this policy process may be higher than those of a proactive policy. This is somewhat surprising because the costs of maintaining
populations at a level at which they are not endangered may occur over a longer period. However, the costs of bringing species
populations back to those levels may be so high that they outweigh the costs of the proactive approach. We develop simple
cost functions that capture the main economic and ecological parameters relevant to our argument and apply them for an assessment
of the costs of common hamster (Cricetus cricetus) conservation in the region of Mannheim, Germany. We find that a proactive approach would have saved between €17.2 and €36.4mn
compared to the existing policy where conservation was delayed until legal requirements forced local policy makers to implement
a comprehensive hamster protection programme.
KeywordsCommon hamster–Conservation management–Conservation costs–Cost assessment–Proactive conservation
Texas Rio Grande Valley Red–crowned Parrots (Psittaciformes: Amazona viridigenalis [Cassin, 1853]) primarily occupy vegetated urban rather than natural areas. We investigated the utility of raw vegetation indices and their derivatives as well as elevation in modelling the Red–crowned parrot’s general use, nest site, and roost site habitat distributions. A feature selection algorithm was employed to create and select an ensemble of fine–scale, top–ranked MaxEnt models from optimally–sized, decorrelated subsets of four to seven of 199 potential variables. Variables were ranked post hoc by frequency of appearance and mean permutation importance in top–ranked models. Our ensemble models accurately predicted the three distributions of interest (x¯ Area Under the Curve [AUC] = 0.904–0.969). Top–ranked variables for different habitat distribution models included: (a) general use–percent cover of preferred ranges of entropy texture of Normalized Difference Vegetation Index (NDVI) values, entropy and contrast textures of NDVI, and elevation; (b) nest site–entropy textures of NDVI and Green–Blue NDVI, and percent cover of preferred range of entropy texture of NDVI values; (c) roost site–percent cover of preferred ranges of entropy texture of NDVI values, contrast texture of NDVI, and entropy texture of Green–Red Normalized Difference Index. Texas Rio Grande Valley Red–crowned Parrot presence was associated with urban areas with high heterogeneity and randomness in the distribution of vegetation and/or its characteristics (e.g., arrangement, type, structure). Maintaining existing preferred vegetation types and incorporating them into new developments should support the persistence of Red–crowned Parrots in southern Texas.
Psittacid Adenovirus-2 (PsAdv-2) was identified in captive orange-bellied parrots ( Neophema chrysogastor) during a multifactorial cluster of mortalities at the Adelaide Zoo, South Australia, and an outbreak of Pseudomonas aeruginosa septicaemia at the Tasmanian Department of Primary Industries, Parks, Water and Environment captive breeding facility, Taroona, Tasmania. This was the first time that an adenovirus had been identified in orange-bellied parrots and is the first report of PsAdv-2 in Australia. To investigate the status of PsAdv-2 in the captive population of orange-bellied parrots, 102 healthy birds from five breeding facilities were examined for the presence of PsAdv-2 DNA in droppings and/or cloacal swabs using a nested polymerase chain reaction assay. Additionally, eight birds released to the wild for the 2016 breeding season were similarly tested when they were recaptured prior to migration to be held in captivity for the winter. PsAdv-2 was identified in all breeding facilities as well as the birds recaptured from the wild. Prevalence of shedding ranged from 29.7 to 76.5%, demonstrating that PsAdv-2 is endemic in the captive population of orange-bellied parrots and that wild parrots may have been exposed to the virus. PsAdv-2 DNA was detected in both cloacal swabs and faeces of the orange-bellied parrots, but testing both samples from the same birds suggested that testing faeces would be more sensitive than cloacal swabs. PsAdv-2 was not found in other psittacine species housed in nearby aviaries at the Adelaide Zoo. The source of the infection in the orange-bellied parrots remains undetermined. In this study, PsAdv-2 prevalence of shedding was higher in adult birds as compared to birds less than one year old. Preliminary data also suggested a correlation between adenovirus shedding prevalence within the breeding collection and chick survival.
The Orange-bellied Parrot is endangered in south-eastern Australia. In the winter it is dispersed over a long band of coastal habitat ranging from Victoria to South Australia. The present model study compares the benefits of habitat management in the Victorian and the South Australian parts of the winter habitat. Various management options are compared in a sensitivity analysis. The results show that management in Victoria has a stronger influence on the population than management in South Australia. The population parameters are subject to considerable uncertainty. The sensitivity of the results to the values assigned to the model parameters is explored. The results are valid over a wide range of the plausible parameter space.
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