Tieleman B Irene
Animal Ecology Group, Centre for Ecological and Evolutionary Studies, University of Groningen, Haren, The Netherlands.
J Anim Ecol. 2009 Mar;78(2):293-5. doi: 10.1111/j.1365-2656.2008.01522.x.
Dark-eyed juncos (Junco hyemalis) from two elevations in the Rocky Mountains of Canada display different life histories. Birds breeding at high elevation face a later and compressed reproductive season during which they raise on average half the number of broods (young) than their low-elevation conspecifics. Fledglings at high elevation are heavier, fatter, and have an increased chance of surviving to 25 days of age. Likewise, survival of adults (males) increases at higher elevation. Put into a broader perspective, high-elevation juncos show the life-history strategy characteristic for low-latitude birds. This raises questions about the mechanisms influencing life-history evolution.
来自加拿大落基山脉两个海拔高度的暗眼灯草鹀（Junco hyemalis）表现出不同的生活史。在高海拔地区繁殖的鸟类面临着更晚且更紧凑的繁殖季节，在此期间，它们平均养育的雏鸟数量只有低海拔同物种鸟类的一半。高海拔地区的雏鸟更重、更胖，活到25日龄的几率也更高。同样，成年（雄性）鸟在更高海拔地区的存活率也会增加。从更广泛的角度来看，高海拔灯草鹀表现出低纬度鸟类特有的生活史策略。这引发了关于影响生活史进化机制的问题。
