Nest-site selection and breeding ecology of Streaked Wren-Babbler (Napothera brevicaudata) in a tropical limestone forest of southern China

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.

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.

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).

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.