ABSTRACT

The Green-and-Gold Tanager (Tangara schrankii) is widely distributed throughout western Amazonia, between 300 and 1650 m, and is a common member of canopy and midstory mixed-species flocks. Although basic nesting aspects are known for this species, detailed information is lacking. This study provides new insights on nesting behaviour and natural history for this species based on 150 nests encountered during eight consecutive nesting seasons in southeastern Peru, Manu National Park. Nests were located between 0.3 and 4.5 m above the ground. The incubation and nestling periods lasted 16 and 13.4 days, respectively. Females conducted 6.2 ± 1.96 off-bouts per day and spent long incubating sessions of 77.4 ± 51.9 min. The length of the incubation bouts and the frequency (trips per day) did not vary across the three stages (early, middle, and late) of the incubation period. The overall daytime nest attentiveness was 65.4% and did not vary along the incubation period. Parents conducted 1.77 ± 1.02 feeding trips per hour. The daily survival rate (0.75) of this species was low compared to other passerines. Our data is consistent with previous T. schrankii nesting descriptions. Nestling period, and feeding rates, however, are much shorter compared to previous reports for other Tangara and related genera. We found that T. schrankii has different nesting strategies, such as locating nests on a variety of substrates, conducting long incubation sessions, fewer off-bouts, and lower feeding rates. These strategies could reduce nest detectability by visual predators, and shorten the nestling period, likely increasing their reproductive success. We suggest that the combination of these nesting traits has allowed T. schrankii to successfully inhabit lowland tropical forests where high predation levels are encountered by nesting birds.

摘要

绿色和金色的唐纳雀（Tangara schrankii）广泛分布于整个亚马逊河西部，介于300至1650 m之间，是冠层和中层混合物种群的常见成员。尽管已知该物种的基本筑巢方面，但缺乏详细的信息。这项研究基于秘鲁东南部的马努国家公园连续八个筑巢季节中遇到的150个巢穴，为该物种的筑巢行为和自然历史提供了新的见解。巢位于地面上方0.3至4.5 m之间。潜伏期和孵化期分别持续16天和13.4天。雌性每天进行6.2±1.96的爆发训练，并花费了77.4±51.9分钟的长时间潜伏期。在潜伏期的三个阶段（早期，中期和晚期），潜伏期的长度和频率（每天的行程）没有变化。白天整个巢的注意力集中度为65.4％，在整个潜伏期没有变化。家长每小时进行1.77±1.02次喂食。与其他雀形目相比，该物种的每日生存率（0.75）低。我们的数据与以前的一致T. schrankii嵌套说明。然而，与其他Tangara及其相关属的先前报道相比，育雏期和摄食率要短得多。我们发现sch。schrankii具有不同的筑巢策略，例如将巢定位在各种底物上，进行长时间的孵育，减少异味，并降低饲喂率。这些策略可能会降低视觉掠食者的巢检测能力，并缩短巢期，从而可能增加繁殖成功率。我们认为，这些筑巢性状的组合使T. schrankii能够成功栖息在低地热带森林中，在那里筑巢鸟类会遇到高捕食水平。