Nesting behavior of the Chestnut-crowned Gnateater, <i>Conopophaga castaneiceps</i> (Aves: Conopophagidae)

The chestnut-crowned gnateater (<i>Conopophaga castaneiceps</i>) inhabits the Andean mountains, from Colombia to Peru, between 500 and 2000 m. Our study provides new information on the nesting biology of <i>C. castaneiceps</i>; specifically, we describe hitherto unknown aspects such as eggs, nestling development, incubation and feeding behaviours. Three nests were monitored during two breeding seasons (2014–2015) in Tatamá National Park, Risaralda, Colombia. Cup nests contained a clutch of two creamy eggs with reddish dots scattered throughout the shell. On average, the parents incubated 58% of their time, with similar duration of the off- (77 ± 48.2 min) and on-bouts (73 ± 41.7 min). A few days before nestlings abandoned the nest (11–12-day-old nestlings), parents conducted 6.8 ± 1.6 feeding trips per hour (N = 25 hours) during the daytime. Based on one nest, the nestling period lasted 17 days, with a growth rate (<i>K</i>) of 0.4. The female had a higher investment during the nestling period, more brooding (t₁₀ = 106.48, <i>P</i> &lt; .001) and more feeding trips (t₁₀ = 7.69, <i>P</i> &lt; .001) compared to the male. Both parents conducted night brooding. Our study shows that nesting traits are conserved among <i>Conopophaga</i> species. Our novel information on nestling growth, incubation and feeding behaviour for <i>C. castaneiceps</i> advances our understanding of the gnateater’s poorly known nesting biology and will be key for future comparative studies.

栗顶蚁鵙（Conopophaga castaneiceps）栖息于安第斯山脉，分布范围从哥伦比亚延伸至秘鲁，栖息海拔介于500至2000米之间。本研究为栗顶蚁鵙（C. castaneiceps）的筑巢生物学提供了全新数据；具体而言，我们描述了该物种此前未被记录的诸多特征，包括卵的形态、雏鸟发育过程、孵卵行为与取食行为。2014至2015年的两个繁殖季期间，我们在哥伦比亚里萨拉尔达省的塔塔马国家公园对三处巢穴进行了监测。该物种的杯状巢内窝卵数为2枚，卵呈奶油色，蛋壳表面散布有红色斑点。亲鸟的日均孵卵占比为58%，离巢时段（77±48.2分钟）与孵卵时段（73±41.7分钟）的持续时长相近。在雏鸟离巢前数日（11至12日龄雏鸟），亲鸟日间每小时的取食频次为6.8±1.6次（观测时长总计25小时）。基于其中一处巢穴的观测数据，雏鸟的育雏期为17天，生长速率（K）为0.4。在育雏期内，雌性亲鸟的投入更高：其暖雏时长（t₁₀=106.48，P<.001）与每小时取食频次（t₁₀=7.69，P<.001）均显著高于雄性。双亲均会在夜间进行暖雏。本研究表明，蚁鵙属（Conopophaga）各物种的筑巢特征具有保守性。我们针对栗顶蚁鵙的雏鸟生长、孵卵与取食行为的全新研究结果，加深了学界对鲜为人知的蚁鵙类筑巢生物学的认知，也将为未来的比较研究提供关键支撑。