First Record of the Breeding Biology of the Biet's Laughingthrush ( <i>Ianthocincla bieti</i> ) in Southwest China

Breeding biology of the poorly known Biet's Laughingthrush (<i>Ianthocincla bieti</i>) was studied in the mixed coniferous and broad-leaved forests at Laojun mountain in southwest China. We discovered two active nests in 2021 and 2024; both were located on bamboo stands, 3.7 and 4.5 m above the ground respectively. The nest is open, bowl- or cup-shaped, and mainly composed of dry grass stems, bamboo branches and leaves. We made direct observations on parent birds, used infrared camera to monitor the breeding events in the nest, and also made video recordings of the incubation and brooding behavior. Both parent birds incubated the eggs and provisioned the nestlings. The incubation period lasted for 15 days. As incubation progressed, incubation-bout duration had no significant difference through the early, middle and late stages. However, during the 15-day nestling period, feeding frequency of parents showed a significant difference among stages, with the highest feeding frequency at the late stage. The length of brooding bouts decreased as the nestlings' age increased. Our observations provide detailed records on the nest, nestlings, and breeding behavior of this endangered laughingthrush for the first time. Based on the known information, we emphasized the importance of alpine bamboo forests for the conservation of this laughingthrush. Moreover, we recommend minimizing anthropogenic disturbance in its breeding ground, and prioritizing a comprehensive survey to assess the current population status in its distribution.