Sovrano Lorena Vanesa, Beltzer Adolfo Héctor, Regner Silvia Alejandra, Giraudo Alejandro Raúl
Instituto Nacional de Limnología (INALI; CONICET-UNL), Paraje El Pozo s/n, Santa Fe (3000), Argentina. E-mail:
Universidad Nacional del Litoral (UNL), Facultad de Humanidades y Ciencias (FHUC), Paraje El Pozo s/n, Santa Fe (3000), Argentina.
Zool Stud. 2024 Dec 27;63:e50. doi: 10.6620/ZS.2024.63-50. eCollection 2024.
The Chestnut-capped Blackbird is a neotropical species that nests in wetlands, which are abundant in South America. However, many of these wetlands face threats of disappearance and degradation, with potential consequences for the species inhabiting them. Here, we carried out a detailed study of the breeding biology of this species and examined variables that influence daily nest survival rates (DSR). We described nest site features, nest morphometry, breeding parameters, estimated the growth curves of nestlings, and recorded the causes of nest failure. We evaluated the effects of nest site features, nest morphometry, nest age and timing of breeding season on the DSR of Chestnut-capped Blackbirds. We expected that DSR would increase with greater nests and higher nest concealment at the beginning of the breeding season. Additionally, we predicted that larger nests would have higher nest survival. We studied the breeding performance of 138 nests in a wetland in central Argentina over three consecutive breeding seasons. Nests were placed 80 ± 21.53 cm above the water. The clutch size was 2.75 ± 0.67 eggs ( = 84 nests), and the brood size was 2.28 ± 0.79 nestlings ( = 49 nests). The most frequent cause of nest failures was predation (60%). The daily nest survival rate (DSR) was 0.96, and the cumulative probability of nest survival in a 29-day breeding cycle was 0.31 ( = 85 nests). As expected, we found a positive association between nest height above the water and DSR, suggesting that nests built further away from the water have increased survival rates. However, we found no effects of nest morphometry or the timing of breeding season on DSR. We emphasize the importance of understanding the breeding performance and the influence of nest site features on the survival of species inhabiting wetlands to implement actions to conserve and protect the population.
栗顶黑鹂是一种新热带物种，在南美洲丰富的湿地中筑巢。然而，这些湿地中的许多都面临消失和退化的威胁，这可能会对栖息其中的物种产生影响。在此，我们对该物种的繁殖生物学进行了详细研究，并考察了影响每日巢存活率（DSR）的变量。我们描述了巢址特征、巢的形态测量、繁殖参数，估计了雏鸟的生长曲线，并记录了巢失败的原因。我们评估了巢址特征、巢的形态测量、巢龄和繁殖季节时间对栗顶黑鹂DSR的影响。我们预计在繁殖季节开始时，随着巢更大且巢的隐蔽性更高，DSR会增加。此外，我们预测更大的巢会有更高的巢存活率。我们在阿根廷中部一个湿地连续三个繁殖季节研究了138个巢的繁殖表现。巢位于水面上方80±21.53厘米处。窝卵数为2.75±0.67枚卵（n = 84个巢），育雏数为2.28±0.79只雏鸟（n = 49个巢）。巢失败最常见的原因是捕食（60%）。每日巢存活率（DSR）为0.96，在29天的繁殖周期中巢存活的累积概率为0.31（n = 85个巢）。正如预期的那样，我们发现水面上方的巢高与DSR之间存在正相关，这表明建在离水更远地方的巢存活率更高。然而，我们没有发现巢的形态测量或繁殖季节时间对DSR有影响。我们强调了解繁殖表现以及巢址特征对栖息在湿地中的物种生存的影响对于实施保护和养护种群行动的重要性。
