Data from: Diet and birdsong: short-term nutritional enrichment improves songs of adult Bengalese finch males

Song is a notable sexual signal of birds, and serves as an honest indicator of male quality. Condition dependence of birdsong has been well examined from the viewpoint of the developmental stress hypothesis, which posits that complex songs assure fitness because learned acoustic features of songs are especially susceptible to early-life stress that young birds experience in song learning periods. The effect of early stress on song phenotypes should be crucial, especially in age-limited song learners which sing stereotyped songs throughout life. However, little attention has been paid to non-learned song features that can change plastically even in adulthood of age-limited song-learners. Although it has been shown that food availability affects song rate in wild songbirds, there is limited evidence of the link between favorable nutritional conditions and song phenotypes other than song rate. Under the prediction that singing behavior reflects an individual’s recent life history, we kept adult Bengalese finch males under high-nutrition or normal diet for a short term, and examined changes in body mass and songs. We found that birds on a high-nutrition diet showed higher song output (e.g. song rate and length) compared with those of the control group, while changes in body mass were moderate. In addition, note repertoire became more consistent and temporal structures got faster in both nutrition and control groups, which indicates that songs were subject to other factors than nutrition. Considering that female estrildid finches, including Bengalese and zebra finches, show a preference toward complex songs as well as longer songs and higher song rate, it is plausible that different aspects of singing behavior signal different male qualities, and provide multifaceted clues to females that choose mates.鸣唱是鸟类显著的性信号，同时可作为雄性个体质量的诚实性指示指标。学界已从发育应激假说（developmental stress hypothesis）的视角对鸣唱的条件依赖性开展了充分研究，该假说提出，复杂鸣唱可保障个体适合度，因为鸣唱的习得性声学特征极易受到幼鸟在鸣唱学习期所经历的早期生活应激的影响。早期应激对鸣唱表型的影响至关重要，尤其是对于终生只会发出定型鸣唱的年龄限制型鸣唱学习者而言。然而，学界极少关注年龄限制型鸣唱学习者即便在成年后仍可发生可塑性变化的非习得性鸣唱特征。尽管已有研究表明，野生鸣禽的食物可获得性会影响其鸣唱率，但关于优质营养条件与除鸣唱率之外的其他鸣唱表型之间关联的证据仍较为匮乏。基于“鸣唱行为可反映个体近期生活史”的预测，我们将成年雄性白腰文鸟短期饲养于高营养饮食组或正常饮食组，并检测其体重与鸣唱的变化。研究发现，相较于对照组，高营养饮食组的鸣禽展现出更高的鸣唱产出量（如鸣唱率与鸣唱时长），而体重变化幅度较为平缓。此外，两组鸣禽的音节库均变得更为一致，时域结构的速率也有所加快，这表明鸣唱还受到营养以外的其他因素调控。考虑到包括白腰文鸟与斑胸草雀在内的雌性梅花雀科鸣禽，均偏好复杂鸣唱、更长时长的鸣唱以及更高的鸣唱率，因此鸣唱行为的不同维度可传递不同的雄性质量信息，并为雌性择偶提供多维度线索，这一推论具备合理性。