生物多样性随纬度变化是自然界的重要现象，而生物的性状差异是生物多样性最直接的呈现。本研究综述了鸟类羽色、鸣声、体重的演化速率随纬度变化的规律，探讨了影响鸟类上述性状演化速率的因素。影响性状演化速率的因素包括姐妹种的竞争、有效种群大小、繁殖期长度、时代时间等。分布区重叠的姐妹种种间竞争和避免杂交的压力大，促进性状的快速分化；小种群漂变速度快，加快性状的演化；高纬度地区鸟类繁殖期短，性选择激烈，加剧性选择性状的演化；世代时间对性状演化的积累有决定性影响。在高纬度地区鸟类羽色和鸣声的演化更快，但低纬度地区同域分布的姐妹种体重分化更大。本研究提出在性状演化的研究中，需要充分考虑谱系影响和解释变量的选择，并建议尝试从鸟类可感知的角度衡量性状的演化，关注羽色和鸣声的相互影响对性状演化速率的作用，增加对亚洲鸟类的研究。 以51对美洲鸟类姐妹种对为研究对象，在已有羽色差异分析的基础上，通过分析其鸣声性状随纬度的变化规律，探讨羽色和鸣声在演化上的相互影响。结果显示，羽色的演化速率在高纬度地区更快，并且近缘种对分布区的重叠程度越大羽色差异也越大；相比于低纬度地区，高纬度地区姐妹种鸣声的时长特征差异更小；而姐妹种鸣声频率特征和颤音特征的差异在高、低纬度地区无显著区别；鸣禽姐妹种鸣声时长差异显著大于非鸣禽姐妹种。本研究结果体现了羽色和鸣声演化速率的权衡，同时也为高纬度地区鸟类性状的快速演化提供了一个反例。

One explanation for the latitudinal gradient of biodiversity is that evolutionary rates of characters, which are important to speciation, vary across latitude. The reasons for the latitudinal gradient in characters’ evolutionary rates include sympatry of sister species, effective population size, breeding season, and generation time. Sister species in sympatry encounter intense interspecific competition and cost of hybridization, which may lead to greater evolutionary rates through character displacement. Genetic drift can accelerate evolutionary rates in populations with a small effective size. Sexual selection characters may undergo greater evolutionary rates in birds at higher latitudes, which have shorter breeding season. There is more accumulated character divergence in species with shorter generation times, even the evolutionary rates is unchanged. In birds, color patterns and song features are essential for territory defense and mate attraction, and body size is a key ecological trait influencing most of life history strategies. Color patterns and song features evolved faster in birds at high latitudes, while body mass undergoes rapid divergence in sister species at low latitudes, but not at high latitudes. At the end of this review, we discuss phylogenetic approach and variable selection in the researching of avian characters’ evolutionary rates. Quantification character divergence from bird's view, and including evolutionary trade-off between color patterns and song features may need to be taken into account in future study. Also more attention should pay on Asian birds. This analysis focused on 51 sister species in America. We analysed the acoustic signals divergence across a latitudinal gradient between sister species, and also build an acoustic-color pattern analytical model in order to research the correlation between the acoustic signal divergence and color pattern divergence. We found that the evolutionary rate of color pattern in birds at higher latitudes is faster than at lower latitudes, and sympathy among diverging clades causes greater divergence of color characteristics at higher latitudes. As for acoustic signals, divergence in duration is less in sister species which habitat in high latitudes, while frequency and trill features are not significantly changed through latitudinal gradients. The evolutionary rate of acoustic signals is greater in songbird than non-songbird. In conclusion, we found the trade-off between song feature and color pattern divergence in birds, and also provide an counter-example about sexual selection characters undergo greater evolutionary rates in birds at higher latitudes.