Red-eared firetail

The red-eared firetail (Stagonopleura oculata), also known as the boorin, is a small finch-like species of bird. It occurs in dense wetland vegetation of coastal to sub-coastal regions in Southwest Australia. Its appearance is considered appealing, with white spots, black barring and vivid crimson marks at the ear and upper tail. Red-eared firetails are usually only glimpsed briefly, if at all, as they move rapidly and discreetly through their habitat. Most observations occur when their soft voice is heard, or in flight when flushed from the dense scrub. Males and females are similar in colouring and bond as lifelong pairs that occupy a territory centred on their roosting and brooding nest site. The species occupies a similar ecological niche to the beautiful firetail (Stagonopleura bella) found in the east of Australia, although unlike other species of the genus they only occasionally group together and are almost never seen in large flocks.

The red-eared firetail is rare in captivity, being neither recommended nor generally permitted, as they require expertise and a large specialised environment to maintain their secretive habits; however, the observations in avicultural literature have supported and contributed to knowledge of its behaviour. Despite their shyness toward other birds and people, they are known to be less so when venturing out to bird feeders. The species is not easily confused with other birds in its native habitat, excepting perhaps the red-browed finch (Neochmia temporalis) that has escaped captivity and bred in the region.

Taxonomy

The red-eared firetail was described by the French zoologists Jean René Constant Quoy and Joseph Paul Gaimard in 1832. They coined the binomial name Fringilla oculata. The description was published in the zoology volume of Dumont d'Urville's account of the expedition aboard the Astrolabe, based on a specimen that Quoy and Gaimard had collected at King George Sound. Their publication preceded the entry as Estrelda oculea in John Gould's Birds of Australia (1848), this later description making an unnecessary emendation to the spelling of the epithet oculata. Gould's Handbook to the Birds of Australia (1865) names the bird Zonæginthus oculeus with a citation to Cabanis' 1853 description under the same name. The specific epithet oculatus (marked with eyes, conspicuous) is a Latin term derived from oculus (eye) that was later interpreted by authors (Gould, Cayley) to refer to the white spots as eye-like; however, Quoy and Gaimard seem to have meant "conspicuous" since they named the bird French: sénégali oculé which refers to the highly noticeable, eye-adjacent red ear patch.

No infraspecific variation for the species is cited in avicultural or ornithological literature. A typical description of a new subspecies, Zonaeginthus oculatus gaimardi, published by G. M. Mathews in 1923 is only mentioned as a synonym for the species. While no subspecies are recognised, several varying characteristics in the population have been identified: a sub-population—near the coast from Cape Arid to Cape Le Grand and islands of the Recherche Archipelago—are notably paler and geographically isolated by a strip of arid land twenty kilometres wide. Johnstone and Storr (2004) reported an individual at Ravensthorpe to have pinkish tips to the feathers on its breast. A description as a subgeneric arrangement, Stagonopleura (Zonaeginthus) oculata, was published in 2006, confirming the presumed alliance to its sister species Stagonopleura (Zonaeginthus) bellus—the beautiful firetail—that was suggested by Gould and subsequent authors.

Earlier names for this population of birds in the Nyungar language were recorded by the field researcher John Gilbert and published in Gould's Birds of Australia and handbook. Similar names with variant spellings were given for the districts of King George Sound, Darling Range, and Perth by Serventy and Whittell in their mid-twentieth century A Handbook of the Birds of Western Australia (with the exception of the Kimberley Division) (1948). A recommended orthography and pronunciation list of all published names has proposed boorin, dwerdengolngani, and djiri in preference to later vernacular. Other names include red-eared firetail finch, Western firetail, red-eared finch, and the ambiguous zebra finch. The IOC World Bird List recommends "Red-eared Firetail" as the preferred English name and orthography. Gilbert, via Gould, reported that the Swan River colonists had named the bird "native sparrow". The attraction of the species to the seed-bearing cones of sheoak (Allocasuarina) inspired the local name of "casuarina finch" in the Pemberton area.

The red-eared firetail is allied to the family Estrildidae of the avian order Passeriformes. Prior to its separation to the genus Stagonopleura, the species was classified as Emblema oculata.

Description

The red-eared firetail is a small grass-finch with black-barred and white-spotted plumage, distinguished by its scarlet bill, black mask, and bright crimson red patch behind the eye and at the rump. The plumage of the upper parts is olive-brown and the breast is buff-brown, both of which are thinly barred black. White spots appear on the blackish underparts. The female closely resembles the male, except when his colouring intensifies during the breeding season.

The adult plumage is crossed with black vermiculated lines, finely at the nape and crown and more strongly at the scapular feathers, upper-wing coverts, back, and the mantle; these sinuous black markings appear on otherwise greyish-brown upperparts. A similar patterning, in a dusky black colour, is finer at the brown throat and cheek and bolder at the grey-buff of the foreneck. The feathers of the underparts—undertail coverts, abdomen and flank—are white with a black margin and there is barring that outlines the distinct spots. The light brown thigh is slightly crossed with black. Paler lines cross the brown coverts under the tail. The secondary flight feathers and coverts are also greyish brown, with grey-black barring. The primaries and their coverts are dark brown; the outer primaries have a thin margin of a paler brown. A deep shade of crimson is apparent on the rump and tail coverts. A thin black band extends across the frons, broadening at the lores and circling the eyes to give a masked appearance, contrasting the distinctive patch of crimson at the ear coverts and scarlet of the bill; this mask is comparatively larger in males when closely observed. The colour of the tail feathers is a dusky shade of brown with fine black barring and the central tail feathers become crimson toward the coverts.

Descriptions of the iris are as red or dark brown, the eye-ring as pale blue, and the legs as dark- or pink-brown. The bill of both sexes is red, although a coating on the bill of the male intensifies its colour during the breeding season. The average size of the adult is around 125 millimetres (mm) in length. The weight of males is 11.4–16.0 grams, females have a narrower range of 12.5–13.6 grams. Using a sample of thirty males and fifteen females, the average length in of the wing is 56.2 mm, bill 11.8 mm, tail 43.7 mm, and tarsus 17.0 mm for the male; the female has an average length of wing at 56.4 mm, bill 11.6 mm, tail 42.4 mm, and tarsus 17.4 mm.

The juvenile plumage resembles the adult, without the deep crimson ear patch and spotted belly. When observed in captivity, the white spots appeared first, beginning at the flank, with the red ear as the last characteristic to emerge. The vermicular bars of the adult plumage are absent at the nape and crown, and are more subdued on the rest of the upper parts. The black at the eyes and lores is absent or nearly so; the distinct red of the upper tail coverts and rump is duller, and underparts are lighter, buff coloured, and mottled rather than spotted. Immature birds usually attain adult plumage within four months although this period is extended if born late in the breeding season. The juvenile's bill begins as a brownish black colour, becoming scarlet between fourteen and twenty two days after fledging, with blue luminous tubercules are evident at the gape. The legs are a duller shade of brown and the naked and white eye-ring is only slightly blue.

The eggshell is pure white, smooth and finely grained, without gloss, but with a salmon-pink tone produced by the contents. The eggs were described as 12 mm × 16 mm in size and oval in shape by Alfred North (1901–14); Forshaw gave the form as "ovate to elliptical ovate". A sample of forty six specimens from nine clutches were taken and noted as 15.9–17.8 mm × 11.9–13.2 mm to give average dimensions of 16.6 mm × 12.4 mm (Johnstone & Storr, 2004). A clutch of six eggs at Torbay (1959) and another of five closer to Albany (1967) were recorded as larger than this average size.

Ecology

The red-eared firetail is a seed eating estrildid, discreet and unusually solitary for an Australian grass finch species. This species often remains unobserved in dense vegetation while foraging in the lower storey. Their presence is revealed by distinctive calls and the bird is most frequently seen when perched high on the limb of a tree such as marri. The individuals form mated pairs rather than grouping. Their individual range is an area around one to two hundred metres across and they may join others while feeding where their territories overlap. Earnest defence of sites only occurs close to the nest, so boundaries between pairs may intersect without incident. Fledglings are eventually fought and driven from the nest site.

The conservation status was at one time listed as rare or of special concern, the current status is as not threatened. It has an estimated global extent of occurrence of 20,000 to 50,000 kilometres squared. The species has been affected by the large-scale clearing of jarrah forest for plantations of pine trees.

The IUCN Red List (2016) has classified the species as being of least concern, citing the entry in Threatened and extinct birds of Australia (Garnett, 1992) that notes while much of its habitat is degraded by salinity or destroyed by changes in agricultural and water management, the usually sedentary habits of the species have not impeded their repopulation of suitable habitat. The population is therefore presumed to be stable.

Distribution

The red-eared firetail is an endemic species of the south-western corner of Australia. The species is uncommon to scarce within its range, although it may be locally common in undisturbed locations, which is typically heavy forests and dense heaths around gullies, rivers, and swamps. The population density increases toward coastal areas of its range, especially at the south. The distribution range along the southern coast extends past Esperance to the east. From the southern coast the species occurs as far north as Cape Naturaliste, Bridgetown, Lake Muir, the Stirling Range, Gairdner River (Calyerup) and the Ravensthorpe Range, and is present off the coast at Bald and Coffin Islands near the city of Albany., The eastern extent of the population at the Esperance Plains region occurs at Cape Arid National Park, and at offshore outcrops of the Recherche Archipelago, such as Middle and Woody Islands. Records are more scarce north of Wungong Brook in the Darling and Stirling ranges, and there is decreasing population density toward inland regions of Fitzgerald River National Park and Ravensthorpe Range. The firetail is rare in the wheat belt and almost non-existent in the Swan Coastal Plain.

The species is thought to breed throughout its distribution range, although this has only been recorded at locations west of longitude 120° East. While regarded as largely sedentary, adults may seasonally relocate outside of the breeding site and immature birds may be driven to new sites where the species is unrecorded in the breeding season.

Changes in land use, such as clearing around frontage at permanent water, has resulted in species becoming absent where it had been previously recorded. Gould described the species as "abundant" around the Swan River colony in 1848, some twenty years after settlement of the region. Serventy noted the species had disappeared from areas near Perth and Pinjarra by the mid-twentieth century, perhaps from the Swan Coastal Plain altogether, though it had persisted at gullies around Mundaring Weir in the Darling Range. The Records (1991) of the Western Australian Museum gave a northernmost location of Glen Forrest in the Darling Range to an area near North Bannister and Mount Saddleback, and confirmed their continued absence from the Swan Coastal plain. However, there are occasional reports of sightings in the largely cleared region, HANZAB notes two seen at Canning Mills in 1997. A study of the population at Cape Le Gand showed a decline in the period 1944–72.

The type locality King George Sound was the source of a later collection made by George Masters for the Australian Museum in 1869. A report on the species for the British journal Ibis by Tom Carter in 1921 noted the occurrence of the species at swamps, common at those dominated by paperbark (Melaleuca) near Albany (1913) and located nests at a wetland near Cape Leeuwin (1916); records are also given for sites around Lake Muir (1913) and at Warren River (March, 1919) in dense scrub below karri forest. Carter had earlier given his observations between Albany and Cape Naturaliste, and noted it was common at springs on limestone hills near Margaret River, Western Australia; he considered a specimen he shot in a karri tree as outside its usual habitat of the dense understorey.