Reduced parental brood visit rate in wild zebra finches (Taeniopygia castanotis) is correlated with high maximum daily ambient temperature

As a result of a warming global climate, understanding how organisms adjust their behaviour to environmental thermal conditions has become an increasingly important question in animal biology. Temperature-driven adjustments in parental care are potentially important given the repercussions on offspring size, quality and survival. In 2015 and 2016, we monitored 83 zebra finch (Taeniopygia castanotis) breeding attempts in the wild. We recorded the frequency of parental visits to the nest together with mean maximum ambient temperature experienced between day 7 and 14 of the nestling period. We found that for each increase of 1 °C in the daytime temperature there was a 0.91% reduction in the hourly rate of parental visits, whilst also accounting for other variables such as nestling age, time of season, and wind speed. Our data suggest that nestlings may receive less food under thermally challenging conditions, which is consistent with recent studies that demonstrate offspring are smaller when reared during periods of high temperature. Understanding the behavioural drivers that may contribute to the production of smaller offspring in extreme heat conditions could prove useful to forecast long-term consequences for fitness triggered by climate change.

随着全球气候变暖，解析生物体如何响应环境温度条件调整自身行为，已成为动物生物学领域愈发关键的研究议题。鉴于温度变化会对后代体型、发育质量与存活产生连锁效应，温度驱动的双亲抚育行为调整具备重要的潜在研究意义。我们于2015年与2016年野外监测了83次斑胸草雀（*Taeniopygia castanotis*）的野生繁殖尝试，记录了亲鸟赴巢饲喂的频率，以及育雏期第7至14日期间所经历的日均最高环境温度。在控制雏鸟日龄、季节时段、风速等其他变量的前提下，我们发现日间温度每升高1℃，亲鸟每小时的饲喂频次便会降低0.91%。我们的数据表明，在热胁迫环境下，雏鸟获得的食物供给可能更少，这与近期相关研究的结论一致——即高温环境下抚育的后代体型更小。解析极端高温条件下引发后代体型偏小的行为驱动机制，或可为预测气候变化引发的适合度长期后果提供理论参考。