Acanthisitta chloris Sparrman, 1787.
OTHER COMMON NAMES
French: Xйnique grimpeur; German: Grenadier; Spanish: Reyezuelo de Nueva Zelanda Fusil.
The riflemen, the smallest living bird species in New Zealand, averages about 3 in (8 cm). There is considerable sexual dichromatism and dimorphism. The female is larger than the male, an odd reversal of the normal state of affairs in bird life. Male dorsal parts are bright yellow-green above; female dorsal parts are striped darker and lighter brown and riddled with red-brown flecks. Both sexes have white ventral parts, white superciliary streaks, and yellowish rumps and flanks. The wings each sport a yellow bar and a white spot posterior to the bar. Bills of both sexes are slightly upturned, the female’s a little more emphatically.
The rifleman is the most cosmopolitan of Acanthisittidae, fairly common and at home throughout most of lowland New Zealand, including the lower two-thirds of North Island, all of South Island, Stewart Island (off the southeast coast of South Island), and the Great Barrier and Little Barrier Islands. Some ornithologists recognize two subspecies—South Island rifleman (Acanthisitta chloris chloris) and North Island rifleman (Acanthisitta chloris granti)—although the two differ only slightly in color, granti trading chloris’s yellow rump for a greenish one.
The rifleman thrives easily in various habitats, including forests, farmlands, disturbed and regenerating habitats, and scrublands. It has even adapted well to landscapes partly composed of non-native plant species.
Riflemen are lively, diurnal birds. The call is a sharp, highpitched, cricket-like zipt, single or in a rapid staccato. Birds spend their days foraging in trees, winging from one to another, usually over an accustomed route, and only rarely on the ground. A rifleman sometimes displays an odd
that Acanthisittidae alone may claim as theirs: an individual will perch on a branch and energetically flick its wings, as if showing off.
FEEDING ECOLOGY AND DIET
Sexual dichromatism relates to feeding methods. Both sexes feed on insects, spiders, and other small invertebrates, but they split up feeding strategies. The male gleans from the leaves of a tree while the female works the bark, both going about their work meticulously and minutely. Thus, either sex has proper camouflage for its particular gleaning grounds. The female’s slightly more upcurved bill may give her an advantage in poking into and prying at loose bark.
Male and female form strong, long-lasting pair bonds. Pairs breed August–January; females lay 2–4 white eggs. A typical pair builds a rather elaborate nest in a tree crevice, sometimes with a dome-like roof, floored and wallpapered inside with spider webs and mosses. The male feeds the brooding female and both parents feed chicks. A bonded pair typically fledge two broods in one season, fledged chicks of the first brood often pitching in to help feed chicks of the later brood.
The species is widespread, fairly common, and protected by law. It is not threatened.
SIGNIFICANCE TO HUMANS
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