Pacific Black Ducks Anas Superciliosa Research Articles

Increasingly detailed insights in animal behaviours using continuous on-board processing of accelerometer data

Background:Studies of animal behaviour, ecology and physiology are continuously benefitting from progressing biologging techniques, including the collection of accelerometer data to infer animal behaviours and energy expenditure. In one of the most recent technological advances in this space, on-board processing of raw accelerometer data into animal behaviours proves highly energy-, weight- and cost-efficient allowing for continuous behavioural data collection in addition to regular positional data in a wide range of animal tracking studies.Methods:We implemented this latest development in collecting continuous behaviour records from 6 Pacific Black Ducks Anas superciliosa to evaluate some of this novel technique’s potential advantages over tracking studies lacking behavioural data or recording accelerometer data intermittently only. We (i) compared the discrepancy of time-activity budgets between continuous records and behaviours sampled with different intervals, (ii) compared total daily distance flown using hourly GPS fixes with and without additional behavioural data and (iii) explored how behaviour records can provide additional insights for animal home range studies.Results:Using a total of 690 days of behaviour records across six individual ducks distinguishing eight different behaviours, we illustrated the improvement that is obtained in time-activity budget accuracy if continuous rather than interval-sampled accelerometer data is used. Notably, for rare behaviours such as flying and running, error ratios > 1 were common when sampling intervals exceeded 10 min. Using 72 days of hourly GPS fixes in combination with continuous behaviour records over the same period in one individual duck, we showed behaviour-based daily distance estimation is significantly higher (up to 540%) than the distance calculated from hourly sampled GPS fixes. Also, with the same 72 days of data for one individual duck, we showed how this individual used specific sites within its entire home range to satisfy specific needs (e.g. roosting and foraging).Conclusion:We showed that by using trackers allowing for continuous recording of animal behaviour, substantial improvements in the estimation of time-activity budgets and daily traveling distances can be made. With integrating behaviour into home-range estimation we also highlight that this novel tracking technique may not only improve estimations but also open new avenues in animal behaviour research, importantly improving our knowledge of an animal’s state while it is roaming the landscape.

Notes on breeding and conservation of birds on Niuafo'ou Island, Kingdom of Tonga

Niuafo'ou lies very isolated in the Pacific, is well forested and not densely populated by humans. These facts as well as the lack of larger rat species make it a refuge for birds rare elsewhere in the region. This paper covers all 17 breeding species and gives breeding data for 14 of them, collected from October 1991 to December 1992. Ten species had a well-defined breeding season of 2?7 months somewhere between September and April, which often differed from other adjacent islands: Audubon's Shearwater Puffinus Iherminieri, Pacific Black Duck Anas superciliosa, Banded Rail Rallus phillippensis, Spotless Crake Porzana tabuensis, Purple Swamphen Porphyrio porphyrio, Barn Owl Tyto alba, Red-vented Bulbul Pycnonotus cafer, Polynesian Starling Aplonis tabuensis nesiotes, and Jungle Myna Acridotheres fuscus. The Blue-crowned Lorikeet Vini australis nested in October, November and July. It did not only breed in tree hollows, but also inside a rotten log on the ground. Other observations suggest that it visits ground holes as well, either for nesting or resting. A breeding colony of Audubon's Shearwater is the first one confirmed for Tonga. Four species nested in the wet and dry season: White-tailed Tropicbird Phaethon lepturus, Pacific Reef-heron Egretta sacra, Pacific Pigeon Ducula pacifica and Polynesian Megapode Megapodius pritchardii. Since September to March is the main breeding season for birds on Niuafo'ou, it is proposed that hunting and egg collecting, both important parts of the local tradition, are restricted to the other months of the year. In case of the endangered Polynesian Megapode we suggest a restriction of egg collecting and propose a translocation programme to another island. Additionally, we suggest that the islets in the crater lake become protected as they are free of feral cats, and some birds occur in higher densities there. Niuafo'ou also deserves attention as resting place for six vagrant and migrant species; large numbers of Wedge-tailed Shearwaters Puffinus pacificus are hunted when they visit between October and June.

Distribution and Abundance of Ducks in the Alligator Rivers Region, Northern Territory

Aerial surveys between 1981 and 1984 were used to identify monthly trends in the abundance of wandering whistling-duck Dendrocygna arcuata, plumed whistling-duck D. eytoni, radjah shelduck Tadorna radjah, Pacific black duck Anas superciliosa, and grey teal A. gibberifrons on five floodplains of the Alligator Rivers region, 250 km east of Darwin in the monsoonal north of the Northern Territory. Ground surveys were conducted during the same period on one of the floodplains, the Magela plain, to provide more detailed information. The Magela floodplain was inhabited by few ducks during the wet season (November to March), but numbers then increased to dramatic peaks in the late dry season. The Nourlangie floodplain and Boggy Plain (a large backswamp of the South Alligator floodplain) showed similar patterns, but the numbers of ducks were usually fewer. Ducks were uncommon on the shallower East Alligator and Cooper floodplains except for relatively brief periods in the wet season. The ground surveys suggested that ducks sought out the persistent swamps that characterise the Magela floodplain in the dry season. Ground surveys also indicated that aerial surveys underestimated densities; on the basis of correction factors calculated from the ground surveys, peak numbers on the five floodplains were roughly estimated to be 400 000 wandering whistling-ducks, 70 000 plumed whistling-ducks, 20 000 radjah shelducks, 50 000 Pacific black ducks, and 50 000 grey teal. Pink-eared ducks Malacorhynchus membranaceus and hardhead Aythya australis were recorded sporadically in low numbers. The Alligator Rivers region acted as a dry season refuge for large concentrations of ducks because of the atypical persistence of freshwaters on the Magela and Nourlangie floodplains and some of the backswamps of the South Alligator, such as Boggy Plain. The large aggregations appear to be unique in Australia.

Kleptoparasitism in Hardheads and Pacific Black Ducks, Including Size-Related Differences

WOODALL, P.F. 1984. Kleptoparasitism in Hardheads and Pacific Black Ducks, including size-related differences. Emu 84: 65-70. Hardheads Aythya australis, diving for freshwater mussels in a lake on the Queensland University campus, were chased by other Hardheads and by Pacific Black Ducks Anas superciliosa. Only Pacific Black Ducks and male Hardheads were successful pirates (9.8% of chases), fewer female Hardheads were pirates and they were never successful. More female Hardhead hosts than males dived during a chase and females lost fewer mussels to Pacific Black Ducks than did males. There was no simple relationship between the numbers of pirates and the probability of successful piracy in a chase. During the period of observation, there was a decline in the median time of chases, particularly of female Hardheads, and also a decline in successful piracy (20 to 5%). It is suggested that male and female (= smaller) Hardheads may form an Evolutionarily Stable Strategy of divers and pirates.

Mecury Concentrations in Ten Species of Australian Waterfowl (Family Anatidae)

Total mercury concentrations in wing muscle of 10 species of waterfowl (Anatidae) collected during 1977 and 1978 in south-eastern Australia ranged from 0.08 � 0.04 (mean � SD) g g-1 wet weight in Australian shelduck Tadorna tadornoides and Pacific black duck Anas superciliosa, to 0.17 � 0.08 g g-1 in freckled duck Stictonetta naevosa. No significant differences in concentrations of mercury in muscle were found between sexes or between juvenile and adult birds. Total mercury concentrations in feathers were 3.01 � 0.09 g g-1 dry weight in Pacific black duck and 3.27 � 1.11 g g-1 in grey teal Anas gibberifrons. A significant positive correlation (r= 0.7783; P<0.01) was found between mercury concentrations in wing muscles and feathers of Pacific black duck.

Use of Habitat and Diurnal Activity of Pacific Black Duck, Chestnut Teal and Grey Teal at Serendip, Victoria

SUMMARYNorman, F. I., L. W. Thomson and J. G. Hamilton, 1979. Use of habitat and diurnal activity of Pacific Black Duck, Chestnut Teal and Grey Teal at Serendip, Victoria. Emu 79: 54–62.The activities of Pacific Black Ducks Anas superciliosa, Chestnut Teal A. castanea (adults and non-flying young) and Grey Teal A. gibberifrons in a fresh-water habitat and the use made of subdivisions within that habitat were studied by making hourly observations on every seventh day for ten weeks. In the study area most ducks spent the day loafing: Black Ducks fed more (28.6% of observations) than Chestnut Teal (18.3%) and Grey Teal spent little time (7.6%) feeding. Most ducks fed early and late in the day. All species shared all divisions of the habitat for feeding and loafing, the main activities considered, but Chestnut Teal used dead trees and logs more for loafing than the other species, which concentrated on isolated short grassland. Younger ducklings spent most time feeding but older ones tended to resemble adults in time spent in various activities.Any competition for food that may occur between the three species could be reduced by nocturnal dispersal to different feeding areas, by selection of different foods or by the selection of differing sizes of the same food as a consequence of the different sizes of bill.