Department of Biology, University of Oxford, Oxford, OX1 3RB, UK.
Messerli Institute, University of Veterinary Medicine, 1210, Vienna, Austria.
Sci Rep. 2024 Nov 19;14(1):27265. doi: 10.1038/s41598-024-76104-7.
Utilising weight cues can improve the efficiency of foraging behaviours by providing information on nutritional value, material strength, and tool functionality. Attending to weight cues may also facilitate the optimisation of object transport. Though some animals' ability to assess weight cues has been determined, research into whether they can apply weight assessment during practical decision making is limited. In this study, we investigate whether Goffin's cockatoos (Cacatua goffiniana) account for relative weight and unequal versus equal weight distribution when making object transport decisions, and whether sensitivity to these cues varies depending on transport mode. We conducted a series of binary choice experiments in which birds could choose to transport one of two identical, non-functional, equally rewarded objects differing only in overall weight (experiment 1) or weight balance (experiment 2) over a short distance. We found that in experiment 1, Goffin's cockatoos preferred to transport light objects over heavy objects and seemed to rely more on weight cues to inform decisions over time, whereas in experiment 2, weight balance cues were ignored. Contrary to our predictions, Goffin's cockatoos did not show increased preference for lighter or more balanced objects when employing higher energy transport modes (flight) compared to lower energy modes (walking). We suggest that this may be due to an insufficient difference in physical effort between transport modes due to the short distance travelled. These findings provide the first evidence of weight cues being considered to optimise object transport in birds.
利用重量线索可以通过提供关于营养价值、材料强度和工具功能的信息来提高觅食行为的效率。关注重量线索也可能有助于优化物体运输。虽然已经确定了一些动物评估重量线索的能力，但关于它们是否可以在实际决策中应用重量评估的研究是有限的。在这项研究中，我们调查了戈芬氏凤头鹦鹉（Cacatua goffiniana）在进行物体运输决策时是否考虑相对重量以及不等重与等重分布的情况，以及它们对这些线索的敏感性是否取决于运输方式。我们进行了一系列二元选择实验，在这些实验中，鸟类可以选择在短距离内运输两个相同的、非功能性的、同等奖励的物体之一，这些物体仅在总重量（实验 1）或重量平衡（实验 2）上有所不同。我们发现，在实验 1 中，戈芬氏凤头鹦鹉更喜欢运输轻物体而不是重物体，并且似乎随着时间的推移更依赖重量线索来做出决策，而在实验 2 中，重量平衡线索被忽略了。与我们的预测相反，当使用更高能量的运输模式（飞行）而不是更低能量的模式（行走）时，戈芬氏凤头鹦鹉并没有表现出对更轻或更平衡的物体的偏好增加。我们认为，这可能是由于短距离旅行导致运输模式之间的体力消耗差异不足所致。这些发现提供了鸟类在优化物体运输时考虑重量线索的第一个证据。
