Climate change and urbanization are two of the most important current global change drivers. However, most studies have focused on these issues in isolation, limiting our ability to predict the impacts of the two in tandem. During hot conditions, many birds reduce foraging activity to minimise heat gain, which can result in costly trade-offs, affecting their ability to maintain body mass. In urban environments however, higher anthropogenic food or water availability could buffer individuals from these potential costs. In this study, we explore the impacts of air temperature on the foraging behaviour and body mass of an urban passerine, the Red-winged Starling, Onychognathus morio in Cape Town, South Africa. In our study system (a university campus), anthropogenic food abundance fluctuates over short timescales, with food being more abundant on weekdays and less abundant on weekends. This system allows us to explore how birds respond to elevated temperatures during days of varying availability of anthropogenic food. We found that individuals increased heat dissipation behaviours with temperature, leading to an apparent trade-off between foraging and heat dissipation. However, despite reduced foraging time, starlings were able to maintain constant food intake rate and body mass with rising temperatures irrespective of the short-term food fluctuations. This suggests that overall food and water abundance in this urban environment buffered individuals from the effects of elevated air temperature, at least within the current range experienced in this system and outside of the breeding season.

气候变化和城市化是当前全球变化最重要的两个驱动因素。然而，大多数研究都孤立地关注这些问题，限制了我们同时预测两者影响的能力。在炎热的条件下，许多鸟类减少觅食活动以尽量减少热量增加，这可能导致代价高昂的权衡，影响它们保持体重的能力。然而，在城市环境中，更高的人为食物或水的可用性可以使个人免受这些潜在成本的影响。在这项研究中，我们探讨了气温对城市雀形目、红翅椋鸟、Onychognathus morio觅食行为和体重的影响在南非开普敦。在我们的研究系统（大学校园）中，人为食物丰度在短时间内波动，工作日食物丰富，周末食物少。该系统使我们能够探索鸟类如何在人为食物供应不同的日子里对升高的温度做出反应。我们发现个体随温度增加散热行为，导致觅食和散热之间的明显权衡。然而，尽管觅食时间减少，但椋鸟能够在温度升高的情况下保持恒定的食物摄入率和体重，而不受短期食物波动的影响。这表明，在这种城市环境中，食物和水的总体丰富程度可以缓冲个人免受气温升高的影响，