Description Red-capped robin

adult male, showing white shoulder markings

the smallest of red robins, red-capped robin 10.5–12.5 cm (4–5 in) long wingspan of 15–19.5 cm (6–8 in), , weighs around 7–9 g (0.25–0.31 oz). males , females of similar size. has longer legs other robins of genus petroica. male has distinctive scarlet cap , breast. upperparts jet black white shoulder bars, , tail black white tips. underparts , shoulder white. colours sharply delineated 1 another. female undistinguished grey-brown above reddish tint crown, , paler underneath dark brown wings , pale buff wing patch. females have reddish tint breast. both sexes have small black bill, , dark brown eyes , legs. immature birds resemble female; second moult, takes place @ around or on year of age males adopt distinctive adult plumage. red-capped robin moults once year, after breeding season takes place between december , april.

female (or immature), southwestern queensland

two red keto-carotenoid pigments, canthaxanthin , adonirubin, responsible redness in red-capped robin s plumage. birds unable synthesize these compounds themselves, , hence need obtain them food. carotenoids costly metabolise , required use in immune function, hence birds need in condition have enough left use in red feathers. makes red plumage advertisement prospective mates. 2001 field study @ terrick terrick national park in victoria found males had greater reproductive success , in better condition moulted brighter plumage following year. however, male age , condition @ time more predict mating success following breeding season. adult males can breed @ 1 year of age , may while yet in non-breeding plumage, less successful @ reproducing @ age. oldest recorded age 5 years , 7 months bird banded near beverley, western australia, in 1990.

a variety of calls have been recorded, described tinkle , blurt songs. these similar across mainland australia distinct on rottnest island; on isolated island, birds linked successive songs.

this species may confused related flame robin (p. phoenicea) , scarlet robin (p. boodang), male can distinguished red crown (white in other 2 species) , smaller size; furthermore, male flame robin has dark grey rather black upperparts. female , immature birds harder distinguish, can differentiated reddish tinge of crown , whiter underparts.