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Open Access Research Article Issue
Investigating how different classes of nest predators respond to the playback of the begging calls of nestling birds
Avian Research 2022, 13 (3): 100044
Published: 22 June 2022
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Begging brings benefits and costs for nestling birds: it can indicate their needs to their parents, but it can also be a cue used by predators to find the nest. The costs, like many variables related to nest predation, can be specific to what kinds of predators are present and their auditory capabilities. These costs and benefits could also be affected by human noise, as noise could disrupt communication to parents and eavesdropping by predators, although human-produced noise might be easily ignored if predators can hear high-frequency components of the begging. We studied nest predation on a generalist bird, the Red-whiskered Bulbul (Pycnonotus jocosus), in a tropical forest in which there are many kinds of nest predators, including birds, mammals and reptiles. In 20 natural nests in which artificial eggs were placed, and subsequently in 140 artificial nests, we broadcast recordings of begging nestlings, with and without traffic noise, at two volume levels. We hypothesized that playback would increase predation relative to a silent control, and that mixing in traffic noise with the begging would decrease predation, as the begging signal was masked. However, we hypothesized that some predators, particularly small mammals with sensitive high-frequency hearing, might ignore the traffic noise. We found that predation was lowest for the control treatment, and lower for treatments mixed with traffic noise than for those without it. Small mammals, however, showed an unexpected pattern, displaying less nest predation in the treatments with traffic noise. Our results demonstrate the human-associated noise can disturb nest predators and influence which kinds of predators use begging to locate nests.

Open Access Research Issue
Nest-site selection and breeding ecology of Streaked Wren-Babbler (Napothera brevicaudata) in a tropical limestone forest of southern China
Avian Research 2017, 8 (1): 28
Published: 20 October 2017
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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.

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