Multiple brooding, reproducing twice or more per year, is an important component of life-history strategies. However, what proximate factors drive the frequency of multiple brooding and its fitness consequences for parents and offspring remains poorly known. Using long-term longitudinal data, we investigated double brooding in a barn owl population in France. We assessed the effects of both extrinsic and intrinsic factors and the consequences of double brooding on fledgling recruitment and female lifetime reproductive success. The occurrence of double brooding in the population, ranging from 0 to 87%, was positively related to the number of rodent prey stored at the nest. Females laying early in the season were more likely to breed twice and the probability of double brooding increased with smaller initial brood size, female age and the storage of wood mice at the nest early in the season. Fledglings from first broods recruited more often (8.2%) than those from single broods (3.8%) or second broods (3.3%), but this was primarily the consequence of laying dates, not brood type per se. Females producing two broods within a year, at least once in their lifetime, had higher lifetime reproductive success and produced more local recruits than females that did not (15.6 ± 8.1 vs. 6.1 ± 3.8 fledglings, 0.96 ± 1.2 vs. 0.24 ± 0.6 recruits). Our results suggests that the fitness benefits of double brooding exceed costs and that within-year variability in double brooding may be related to heterogeneity in individual/territory quality.

中文翻译：

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雌性仓n双重育雏的直接原因和适宜性后果。

多次繁殖，每年繁殖两次或多次，是生活史策略的重要组成部分。但是，什么因素驱动多重育雏的频率及其对父母和后代的适应性后果仍然鲜为人知。使用长期的纵向数据，我们调查了法国仓bar种群中的双亲繁殖。我们评估了外在因素和内在因素的影响，以及双重育雏对新生雏鸟和女性终生生殖成功的影响。种群中双亲繁殖的发生率在0％到87％之间，与巢中储存的啮齿动物的猎物数量成正相关。在本季节早期产蛋的雌性繁殖的可能性更高，并且随着初始母体尺寸的减小，再次繁殖的可能性增加，雌性年龄和木鼠在季节早期在巢中的存储。与单亲（3.8％）或第二亲（3.3％）相比，来自第一亲代的雏鸟的吸收率更高（8.2％），但这主要是产卵日期的结果，而不是亲本类型。雌性在一年之内至少育成两次，一生中至少一次，具有较高的终生繁殖成功率，并且与没有雌性的雌性相比，雌雄繁殖的数量更多（15.6±8.1 vs. 6.1±3.8 vs. 0.96±1.2 vs. 0.24±0.6 ）。我们的结果表明，双重育雏的适应性优势超过了成本，而且双重育雏的年内变异性可能与个体/地区质量的异质性有关。8％）或第二育雏（3.3％），但这主要是产卵日期的结果，而不是育雏类型本身。雌性在一年之内至少育成两次，一生中至少一次，具有较高的终生繁殖成功率，并且与没有雌性的雌性相比，雌雄繁殖的数量更多（15.6±8.1 vs. 6.1±3.8 vs. 0.96±1.2 vs. 0.24±0.6 ）。我们的结果表明，双重育雏的适应性益处超过成本，而且双重育雏的年内变异性可能与个体/地区质量的异质性有关。8％）或第二育雏（3.3％），但这主要是产卵的结果，而不是育雏类型本身。雌性在一年之内至少育成两次，一生中至少一次，具有较高的终生繁殖成功率，并且与没有雌性的雌性相比，雌雄繁殖的数量更多（15.6±8.1 vs. 6.1±3.8 vs. 0.96±1.2 vs. 0.24±0.6 ）。我们的结果表明，双重育雏的适应性益处超过成本，而且双重育雏的年内变异性可能与个体/地区质量的异质性有关。8羽幼雏，0.96±1.2对0.24±0.6新手。我们的结果表明，双重育雏的适应性优势超过了成本，而且双重育雏的年内变异性可能与个体/地区质量的异质性有关。8羽幼雏，0.96±1.2对0.24±0.6新手。我们的结果表明，双重育雏的适应性益处超过成本，而且双重育雏的年内变异性可能与个体/地区质量的异质性有关。