Breeding biology of the red-capped robin

Abstract

The breeding biology of the red-capped robin (Petroica goodenovii) (Petroicidae) was studied over two breeding seasons (2000–02) in Terrick Terrick National Park, Victoria. Breeding commenced in August and the last offspring fledged in January. Only females developed brood patches, built nests and incubated. However, both sexes fed the young. Clutch size ranged from one to three eggs, with a mean of 2.1, with clutches of three occurring relatively early in the season. For clutches of two, the period from laying of the first egg to hatching was 14 or 15 days, with a mean of 14.2. The time from hatching to fledging was 13–15 days, with a mean of 14. In all, 34% of nesting attempts successfully fledged offspring. On average, 0.62 fledglings were produced per nesting attempt, whilst 0.57 offspring reached independence. Nesting success peaked in October. Predation appears to be responsible for almost all nest failure, and predation rate varied over the season. Breeding pairs produced 0–3 broods per season (0–5 independent fledglings) and pairs that began nesting early in the season produced a greater number of independent offspring. Nestling weight was affected by both laying date and brood size. A comparative analysis within the Petroicidae, controlled for body size, revealed that species endemic to Australia have shorter incubation periods, and species from semi-arid and dry woodlands have longer incubation periods than other species. Findings from this study are discussed in relation to the breeding ecology of other members of the Petroicidae.