Background The breeding information of most birds in Asian tropical areas,especially in limestone forests,is still poorly known. The Streaked Wren-Babbler (Napothera brevicaudata) is an uncommon tropical limestone bird with a small range. We studied its nest-site selection and breeding ecology,in order to understand the adaptations of birds to the conditions of tropical limestone forest in southern China.

Methods We used methods of systematical searching and parent-following to locate the nests of the Streaked Wren-Babbler. We measured characteristics of nest sites and rock cavities. Data loggers and video cameras were used to monitor the breeding behavior.

Results All the observed nests of the Streaked Wren-Babbler were placed in natural shallow cavities or deep holes in large boulders or limestone cliffs. The great majority (96.6%) of Streaked Wren-Babbler nests had three eggs with an average fresh weight of 3.46 ± 0.43 g (n = 36,range 2.52?4.20 g). Most (80.4%) females laid their first eggs between March and April (n = 46). The average incubation and nestling period of the Streaked Wren-Babbler was 10.2 ± 0.4 days (n = 5,range 10?11 days) and 10.5 ± 0.8 days (n = 6,range 9?11 days),respectively. Most (87.9%) nests had at least one nestling fledge between 2011 and 2013 (n = 33).

Conclusions Our study suggests that several features of the breeding ecology of the Streaked Wren-Babbler,including building nests in rocky cavities,commencing breeding earlier than most species,and reducing foraging times during the incubation period,are well-adapted to the unique habitat of tropical limestone forest.