Search

We report the depredation by a single Eastern Barn Owl Tyto javanica delicatula on prospecting White-faced Storm Petrels Pelagodroma marina during the re-establishment phase of a colony on Big Island, off Port Kembla, New South Wales, Australia in 2018. Storm petrels were likely extirpated from this colony 56 years previously when invasive weeds rendered their habitat inaccessible. Restoration of vegetation together with storm petrel call broadcasting, commencing in 2014, resulted in significant increases in prospecting numbers, culminating in breeding (three pairs) in the 2017/18 austral summer season. A significant depredation event (> 59 adults) occurred between August and September 2018, providing a set-back to colony establishment. Previously, barn owl depredation on Big Island had been limited to Silver Gulls Chroicocephalus novaehollandiae as prey. However, in the 2018/19 season, the gulls commenced nesting later than usual. The delay appeared to cause the owl to switch target prey. Despite the intense depredation pressure, at least two pairs of storm petrels attempted to breed in the 2018/19 season and 10 birds were trapped and banded at the commencement of the 2019/20 season. Discovery of the mainland roost of the owl was attempted between the two seasons, and its potential death by car strike was investigated. Our findings show that even a single individual predator can have significant impacts on seabird colonies establishing or re-establishing in island environments, especially those under restoration. [ABSTRACT FROM AUTHOR]

An isolated population of Livistona australis (R. Br.) Mart. has been impacted by almost a century of browsing by European rabbits, Oryctolagus cuniculus, on Cabbage Tree Island, Australia. Ongoing adult mortality was documented in this study (n=19) between 1992 and 2001 in addition to a lack of seedling recruitment. Structural failure of the palm trunk or subsidence of the substrate was the prime cause of death in this palm population (63%) with natural senescence of mature palms making up the remainder of the sample. This represents an annual decline of 0.4% per annum and if continued without further recruitment would result in the adult population halving in 125 years. Rabbits were eradicated from the island a decade ago, and the recovery of the vegetation, including palm seedlings, gives hope that the hiatus in recruitment will not negatively impact on the structure of this unique island rain forest. [ABSTRACT FROM AUTHOR]

Abstract: The flesh-footed shearwater (Puffinus carneipes) is a migratory seabird that ranges widely across the Pacific and Indian Oceans. The principal breeding populations are in Australia and New Zealand. The only breeding site in eastern Australia is on Lord Howe Island. Despite it being afforded a high level of legislative protection, the population on Lord Howe Island has declined substantially during the last few decades. The total extent of nesting habitat in 2002 was 24.3ha, a reduction of 13.4ha (35.6%) since 1978. Loss of nesting habitat was associated with increased urbanisation, the adverse impact of which extended beyond the footprint of buildings and gardens. In 2002, overall burrow density was 0.123 per m2 and the total number of burrows was estimated to be 29,853±5867, a decline of about 19.0% since 1978. A substantial decline in burrow density was evident in the colony where loss of habitat to urbanisation had been greatest. In 2002, 58% of burrows were occupied by breeding birds, and the total population size was estimated to be 17,462 breeding pairs. Breeding success (the proportion of eggs that produced fledglings) was 50%, but was lowest in the most urbanised colony. To avert further declines in the population of flesh-footed shearwaters on Lord Howe Island major changes in land use practices, enforced through appropriate legislation, are needed, together with reductions in the level of seabird bycatch in fisheries operations and in the amount of plastics that litter the world’s oceans. [Copyright &y& Elsevier]

Objectives: The objective of this study was to investigate the silver gull as an indicator of environmental contamination by salmonellae and carbapenemase-producing Enterobacteriaceae (CPE) in south-east Australia.Methods: A total of 504 cloacal samples were collected from gull chicks at three nesting colonies in New South Wales, Australia [White Bay (n = 144), Five Islands (n = 200) and Montague Island (n = 160)] and were examined for salmonellae and CPE. Isolates were tested for carbapenemase genes and susceptibility to 14 antibiotics. Clonality was determined by PFGE and MLST. Genetic context and conjugative transfer of the carbapenemase gene were determined.Results: A total of 120 CPE of 10 species, mainly Escherichia coli (n = 85), carrying the gene blaIMP-4, blaIMP-38 or blaIMP-26 were obtained from 80 (40%) gulls from Five Islands. Thirty percent of birds from this colony were colonized by salmonellae. Most isolates contained the gene within a class 1 integron showing a blaIMP-4-qacG-aacA4-catB3 array. The blaIMP gene was carried by conjugative plasmids of variable sizes (80-400 kb) and diverse replicons, including HI2-N (n = 30), HI2 (11), A/C (17), A/C-Y (2), L/M (5), I1 (1) and non-typeable (6). Despite the overall high genetic variability, common clones and plasmid types were shared by different birds and bacterial isolates, respectively.Conclusions: Our data demonstrate a large-scale transmission of carbapenemase-producing bacteria into wildlife, likely as a result of the feeding habits of the birds at a local waste depot. The isolates from gulls showed significant similarities with clinical isolates from Australia, suggesting the human origin of the isolates. The sources of CPE for gulls on Five Islands should be explored and proper measures applied to stop the transmission into the environment. [ABSTRACT FROM AUTHOR]

The Providence Petrel (Pterodroma solandri) currently breeds only on Lord Howe and Phillip Islands and is globally threatened. It once bred on Norfolk Island in large numbers but was extirpated by the late 18th century, greatly reducing the influx of marine-derived nutrients in the form of droppings, and failed eggs and chicks. This lack of nutrients has impaired the health of the remaining native forests on Norfolk Island. The re-establishment of a colony of Providence Petrels on Norfolk Island would not only provide another viable breeding colony of this threatened species but is essential to restore ecosystem function on Norfolk Island. This paper investigates the biology of Providence Petrel chicks as a prerequisite for the translocation of this species to Norfolk Island from Lord Howe. Petrels are highly philopatric, so only chicks not yet imprinted at their natal colony can be translocated. We investigated the timing of first emergence from the burrow, growth and provisioning of chicks on Lord Howe Island, and developed selection and ageing criteria for translocation, together with appropriate feeding regimes. Such information is critical for the success of the proposed translocation. [ABSTRACT FROM AUTHOR]

Summary Of all the introduced mammalian pests, rodents are the most common invaders of islands and have triggered numerous extinctions around the globe. They have a short gestation period and large litter size, giving them the ability to colonise new areas rapidly. The same biological traits make them difficult to eradicate. Although the biodiversity benefits of removing exotic rodents from islands are increasingly being recognised, there are few published analyses of eradication attempts that critically evaluate eradication tools. This study examined the response of House Mouse ( Mus musculus) populations to an eradication operation on Montague Island, Australia. While the specific impacts of mice have not been studied on this particular island, elsewhere they have been shown to have negative impacts on a range of species including plants, invertebrates, lizards and seabirds. On Montague Island, mouse abundance across different habitats was examined using mark-recapture data collected before and after the deployment of brodifacoum baits. Data obtained before baiting showed significantly lower numbers of mice in sites dominated by exotic grass compared with those dominated by native vegetation. Mouse numbers overall were declining during winter and the population was not breeding, making this an optimal time to undertake the eradication. Trapping immediately after the initial bait drop failed to capture any survivors, and no individuals have been detected during the 3 years since the deployment of baits. This study demonstrated that both small and large baits (0.6 and 2 g pellets) were effective in eradicating the House Mouse from Montague Island. While present, mice were probably slowing the re-establishment of native vegetation by grazing seedlings and consuming seeds. With this pest now gone, the process of natural regeneration is expected to accelerate. The eradication of the House Mouse from Montague is likely to have other positive effects on the island's biodiversity. The operation itself contributed to enhancing local capacity to eradicate exotic rodents from larger or more complex islands. [ABSTRACT FROM AUTHOR]

The article discusses a study on the plastic foraging behavior of Puffinus carneipes, also known as Flesh-Footed Shearwaters, on Lord Howe Island, Australia and its implications for fishery interactions. The repeated-weighing technique was used in the study. The study procedure included estimating food consumption, determining their attendance behavior, and determining their meal size and feeding frequency.