Hatching late in the season requires flexibility in the timing of song learning

Most songbirds learn their songs from adult tutors, who can be their father or other male conspecifics. However, the variables that control song learning in a natural social context are largely unknown. We investigated whether the time of hatching of male domesticated canaries has an impact on their song development and on the neuroendocrine parameters of the song control system. Average age difference between early- and late-hatched males was 50 days with a maximum of 90 days. Song activity of adult tutor males decreased significantly during the breeding season. While early-hatched males were exposed to tutor songs for on average the first 99 days, late-hatched peers heard adult song only during the first 48 days of life. Remarkably, although hatching late in the season negatively affected body condition, no differences between both groups of males were found in song characteristics either in autumn or in the following spring. Similarly, hatching date had no effect on song nucleus size...绝大多数鸣禽都会从成年导师处习得鸣唱——这些导师既可以是它们的亲生父亲，也可以是其他同种雄性个体。然而，在自然社交场景下调控鸣唱学习的核心变量，目前仍未得到充分阐释。本研究以雄性家养金丝雀为对象，旨在探究其孵化日期是否会对鸣唱发育以及鸣唱控制系统（song control system）的神经内分泌参数（neuroendocrine parameters）产生影响。早孵化与晚孵化雄性个体的孵化时间平均相差50天，最大差值可达90天。成年导师雄性的鸣唱活跃度在繁殖季期间会显著降低。早孵化雄性个体在出生后的前99天内平均可接触到导师鸣唱，而晚孵化的同龄个体仅在出生后的前48天内能够听到成年鸣唱。值得注意的是，尽管季末孵化会对雄性个体的身体状况产生负面影响，但两组雄性在鸣唱特征上均未表现出显著差异——无论是在秋季还是次年春季。同理，孵化日期对鸣唱核团（song nucleus）的大小也无显著影响……