Buff-sided robin

Distribution

The buff-sided robin occurs in suitable habitat within northern coastal drainage basins from the Kimberley region of north-west Western Australia, the Top End of the Northern Territory to the north-western Gulf of Carpentaria in Queensland.

In Western Australia the buff-sided robin occurs within the Central Kimberley, Northern Kimberley and Ord Victoria Plain IBRA Bioregions with scattered records from King Edward River, Prince Regent River, King Leopold Ranges, Drysdale River/Kalumburu, Mitchell River, Mitchell Plateau, Fitzroy River, Geikie Gorge, Pentecost River, Wyndham and Kununurra.

In the Northern Territory the buff-sided robin occurs within the Victoria Bonaparte, Darwin Coastal, Arnhem Coast, Pine Creek, Daly Basin, Gulf Coastal and Gulf Fall and Uplands IBRA Bioregions. In the western Northern Territory the range of the buff-sided robin extends from the Western Australian border to Kakadu National Park within the Keep River, Victoria River, Fitzmaurice River, Moyle River, Daly River, Darwin River, Finniss River, Adelaide River, Mary River, Wildman River, West Alligator River and East Alligator River catchments. It is absent from eastern Arnhem Land, but occurs in eastern Northern Territory within the Roper River, Limmen Bight River, McArthur River, Robinson River, Calvert River and Settlement Creek drainage basins.

In north-west Queensland the buff-sided robin occurs in the Gulf Plains IBRA Bioregion, with all known records located within the Settlement Creek and Nicholson River drainage basins. Within these catchments populations are known from the Gregory River, Nicholson River, Boodjamulla National Park and Lagoon Creek .The buff-sided robin occurs over a very large range area and while the population trend is declining, the decrease is not believed to be sufficiently rapid to meet the threshold for listing as vulnerable under IUCN population trend criterion . The suspected declining trend has been attributed to the destruction and degradation of the riparian habitat of the buff-sided robin by cattle and feral animals. The population size has not been determined, however it is also not considered to approach thresholds for listing as vulnerable under IUCN population size criterion.

Potential threats to populations of the buff-sided robin are related to the direct and indirect actions of humans , including atmospheric pollution leading to climate change, altered fire regimes, pastoralism , introduction of feral animals, removal of apex predators , land clearing, agricultural and water resource development and weed invasion.

Status

The buff-sided robin is listed as ''least concern'' by the IUCN and is listed as ''near threatened'' in the Northern Territory.The buff-sided robin occurs over a very large range area and while the population trend is declining, the decrease is not believed to be sufficiently rapid to meet the threshold for listing as vulnerable under IUCN population trend criterion . The suspected declining trend has been attributed to the destruction and degradation of the riparian habitat of the buff-sided robin by cattle and feral animals. The population size has not been determined, however it is also not considered to approach thresholds for listing as vulnerable under IUCN population size criterion.

Potential threats to populations of the buff-sided robin are related to the direct and indirect actions of humans , including atmospheric pollution leading to climate change, altered fire regimes, pastoralism , introduction of feral animals, removal of apex predators , land clearing, agricultural and water resource development and weed invasion.The buff-sided robin has been recorded in a range of conservation reserves. In Western Australia it occurs in Geikie Gorge National Park , Prince Regent National Park and Parrys Lagoons Nature Refuge . In the Northern Territory it occurs in Keep River National Park , Judbarra/Gregory National Park , Giwining/Flora River Nature Park , Tjuwaliyn Hot Springs Nature Park , Litchfield National Park , Djukbinj National Park , Charles Darwin National Park , Harrison Dam Conservation Area , Mary River National Park , Nitmiluk National Park , Kakadu National Park , Elsey National Park , Limmen National Park , Barranyi National Park and Caranbirini Conservation Reserve . In Queensland it occurs in Boodjamulla National Park.

Habitat

The buff-sided robin is largely confined to dense riparian vegetation and subcoastal and sandstone monsoon vine thickets. At riparian sites it prefers thickets of freshwater mangrove, pandanus and bamboo. The core riparian forest habitat of the buff-sided robin is characterised by canopy and sub-canopy trees including ''Melaleuca leucadendra'', ''Nauclea orientalis'', ''Ficus'', ''Terminalia'', ''Pandanus aquaticus'' and ''Barringtonia acutangula''. Buff-sided robins are strongly associated with these dense, closed canopy vegetation communities, rarely venturing into adjacent drier and more open forest types. Buff-sided robins have been reported occasionally from tidally influenced mangrove communities near the coast.

Observations of the habitat of the buff-sided robin were provided by Elsey, who described it as living in "mangroves" on the Victoria River, a reference to the freshwater mangrove that occurs on the lower banks of freshwater reaches of rivers in the region. Whitlock confirmed Elsey's habitat observations on the Victoria River, reporting that the buff-sided robin was "''...one of the most attractive inhabitants of the river forests, to which it seemed to be almost exclusively confined''" and that it "''...favoured thickets of freshwater mangroves''". Hill described the buff-sided robin on the McArthur River as being "''Found in thick scrub and timber in sheltered localities, generally near water''". Barnard described it as ''"...common along the water-courses and in the brush growing at the foot of the sandstone bluffs"'' in the McArthur River catchment, the latter comment referring to dry monsoon vine thickets associated with sandstone escarpments. At the eastern extremity of its range on the Gregory River the buff-sided robin was reported by McClennan to occur in riverine habitat and "''...when disturbed makes for the pandanus growing along the river-banks, where it is usually to be found at other times, and in which it doubtless nests.''"

Reproduction

Breeding occurs throughout the range of the buff-sided robin, with most breeding and nesting activity occurring across the warmer months and wet season between October and March with occasional dry season nesting records. Clutch size is generally two and eggs range in size from 17.8 to 20.3 mm in length. The eggs vary considerably in terms of colouration, with a ground colour of light green to dark olive-green and with reddish brown, chestnut or purplish-buff markings. Time between hatching and fledging of young is unknown. Buff-sided robin nests are occasionally targeted by interspecific avian brood parasites . J.P. Rogers observed buff-sided robin adults feeding an immature cuckoo, presumed to be a black-eared cuckoo , on the Fitzroy River.

Buff-sided robin nests are located close to water in dense vegetation and are established on a horizontal or vertical fork of a tree or shrub, commonly at a height of 1 to 3 m and occasionally at greater heights. Nests range in size from 7.3 to 10.2 cm and 2.8 to 5.6 cm . Nests are loosely constructed from twigs, shreds of bark , vines, roots, and grass, bound with cobwebs and sometimes lined with material such as grass, rootlets and feathers.

Food

The buff-sided robin is a diurnal insectivore, predominantly hunting by sallying from a perch onto a hard substrate remote from the bird, a predatory method that relies on observation, direct flight towards prey followed by capture. An observational study suggested that 95% of successful foraging actions by the buff-sided robin are sally strikes onto a surface and the remaining 5% are hawking . A small percentage of prey is taken from other surfaces, including the trunks, branches and foliage of vegetation. Most hunting is undertaken close to the ground, with 85% of foraging observations being within 0 to 3 m from the ground surface.

Detailed studies of the diet have not been undertaken, however prey items are known to include a range of decapods, spiders and insects, including beetles , ants and larval moths and butterflies .

Predators

The buff-sided robin occurs over a very large range area and while the population trend is declining, the decrease is not believed to be sufficiently rapid to meet the threshold for listing as vulnerable under IUCN population trend criterion . The suspected declining trend has been attributed to the destruction and degradation of the riparian habitat of the buff-sided robin by cattle and feral animals. The population size has not been determined, however it is also not considered to approach thresholds for listing as vulnerable under IUCN population size criterion.

Potential threats to populations of the buff-sided robin are related to the direct and indirect actions of humans , including atmospheric pollution leading to climate change, altered fire regimes, pastoralism , introduction of feral animals, removal of apex predators , land clearing, agricultural and water resource development and weed invasion.