ABSTRACT Declines in reproductive performance among older age classes have been reported in many bird and mammal species, and are commonly presented as demonstrating reproductive senescence. However, no declines in performance could be demonstrated in studies of several bird species. We measured reproductive performance in Common Terns (Sterna hirundo) of known age (2–28 yr) during a 19-yr period at a site in Buzzards Bay, Massachusetts, USA. We measured 6 components of reproductive performance and used generalized additive mixed models (GAMMs) in a Bayesian framework to analyze dependence of each measure on parental age, while controlling for variations among years and indices of individual quality. Four measures of performance improved (earlier laying date, higher values of clutch size, fledging success, and productivity) with age, most rapidly between ages 2 and 10 yr; egg mass and hatching success varied only slightly with age. No measure of performance showed reversals among the older age classes; fledging success and productivity continued to increase through at least age 22 yr. These findings are consistent with results from an earlier study of the same species. Continued increase in reproductive performance through the oldest age classes is not incompatible with “reproductive senescence” (decline in physiological or other functions required for successful reproduction) if either reproductive effort or efficiency continue to increase. Studies within our population have yielded no evidence for age-related increase in reproductive effort, but 3 studies have suggested that older Common Terns can raise chicks more successfully than younger birds without increasing reproductive effort, probably by more efficient foraging and chick provisioning. Our findings suggest that Common Terns offset reproductive senescence by continuing to improve efficiency through at least age 22 yr. Age-related changes in efficiency should be investigated in other species with similar life-history traits. LAY SUMMARY We studied Common Terns (Sterna hirundo) at a breeding colony in Massachusetts from 1970 until 2003: we banded chicks when they hatched so that we could determine their age when they returned to breed at the same site in subsequent years. The terns' breeding success continued to improve with age throughout their lives and was still increasing among birds that were 22 years old. Common Terns continually improve their skills at finding fish and provisioning their chicks, even after 20 years of practice.

中文翻译：

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普通燕鸥 (Sterna hirundo) 的繁殖性能在高龄组中并未下降

摘要 在许多鸟类和哺乳动物物种中已经报道了老年群体中生殖能力的下降，并且通常表现为生殖衰老。然而，在对几种鸟类的研究中没有证明性能下降。我们在美国马萨诸塞州秃鹰湾的一个地点测量了 19 年期间已知年龄（2-28 岁）的普通燕鸥 (Sterna hirundo) 的繁殖性能。我们测量了生殖性能的 6 个组成部分，并在贝叶斯框架中使用广义加性混合模型 (GAMM) 来分析每个测量对父母年龄的依赖性，同时控制年份和个体质量指数之间的变化。四个性能指标随着年龄的增长而提高（更早的产蛋日期、更高的离合器尺寸值、羽翼未丰和生产力），在 2 至 10 岁之间最快；卵量和孵化成功率随年龄仅略有不同。没有任何表现衡量指标显示年龄较大的阶层出现逆转；初出茅庐的成功和生产力至少在 22 岁时继续提高。这些发现与早期对同一物种的研究结果一致。如果生殖努力或效率继续增加，那么在最老的年龄段继续提高生殖能力与“生殖衰老”（成功生殖所需的生理或其他功能下降）并不矛盾。对我们人群的研究没有得出与年龄相关的生殖努力增加的证据，但 3 项研究表明，在不增加繁殖力的情况下，年长的普通燕鸥可以比年轻的鸟类更成功地饲养小鸡，这可能是通过更有效的觅食和小鸡供应。我们的研究结果表明，普通燕鸥通过至少在 22 岁之前持续提高效率来抵消生殖衰老。应在具有相似生活史特征的其他物种中研究与年龄相关的效率变化。LAY 总结 我们从 1970 年到 2003 年在马萨诸塞州的一个繁殖地研究了普通燕鸥 (Sterna hirundo)：我们在雏鸟孵化时给它们打了条带，这样我们就可以确定它们在随后几年回到同一地点繁殖时的年龄。燕鸥的繁殖成功率在其一生中随着年龄的增长而不断提高，并且在 22 岁的鸟类中仍在增加。