Summary
1. | The Yellow-tniled Thornbill is gregarious and associates in flocks during the breeding and non-breeding periods. | ||||
2. | The nesting season is in the spring, October being the peak month. This is correlated with the rising temperature gradient. | ||||
3. | Both the male and the female assist in the construction of the nest. The same nest site may he used by a particular pair for several successive years, and only one nest may be built each season. | ||||
4. | The incubation and fledging periods are 18–20 and 17–19 days respectively. | ||||
5. | The female alone incubates. Both parents feed the nestlings and fledglings. Co-operative feeding of nestlings by progeny from previous broods commonly occurs. | ||||
6. | Up to four broods may be raised in a season. | ||||
7. | Breeding mortality data indicate that the Yellow-tailed Thornbill is a moderately successful breeder and that most young hatched in successful nests are fledged. | ||||
8. | The mean clutch size is 3·2 ± 0·5. A seasonal trend in mean clutch size occurs. | ||||
9. | The species is a common host of the Golden Bronze-Cuckoo which apparently removes one of the thornbill eggs when depositing its own. Most cuckoo chicks that hatch are fledged. |