Heterogeneity in individual quality in birds: overall patterns and insights from a study on common terns

While life-history theory predicts a trade-off between reproduction and survival, positive covariance, indicative of heterogeneity in individual quality, is often reported among individuals from natural populations. We review longitudinal studies of wild bird populations that test the relationship between annual reproductive success and lifespan and find the majority to report a positive correlation, while none reports a negative correlation. Heterogeneity in individual quality in resource acquisition, masking resource-based trade-offs, therefore appears to be common in birds. Considering that there is little evidence for heritable variation in fitness, heterogeneity in individual quality among adults may be due to life-long effects of developmental conditions. In a 20-year case study on common terns (Sterna hirundo), we test for life-long effects of cohort quality and within-cohort nest quality, but find no significant effects on long-term proxies of quality. Since other studies do fin...

尽管生活史理论（life-history theory）预测繁殖与存活之间存在权衡，但自然种群个体间常被报道存在正协方差，该现象指向个体质量异质性。我们综述了检验野生鸟类种群年度繁殖成功率与寿命间关系的纵向研究，发现多数研究报告了正相关关系，且无一项研究报道负相关。因此，资源获取维度的个体质量异质性会掩盖基于资源的权衡，这一情况在鸟类中似乎颇为普遍。鉴于目前鲜有证据表明适合度存在遗传变异，成年个体间的质量异质性可能源于发育条件的终生效应。在一项针对普通燕鸥（Sterna hirundo）的20年案例研究中，我们检验了同群质量与同群内巢址质量的终生效应，但未发现二者对长期质量替代指标存在显著影响。由于其他研究确实 fin...