Thomas RJ
School of Biological Sciences, University of Sussex
Anim Behav. 2000 Apr;59(4):787-791. doi: 10.1006/anbe.1999.1360.
Stochastic dynamic programming (SDP) is a computational technique that has been used to model daily routines of foraging in small birds. A diurnal bird must build up its fat reserves towards dusk in order to avoid starvation during the night, when it cannot feed. However, as well as the benefits of avoiding starvation, storing fat imposes costs such as an increased predation risk and higher flight and metabolic costs. There is therefore an optimal level of fat reserves for a bird to reach at dusk in order to survive overnight without being left with excessive fat reserves at dawn. I tested a prediction common to all SDP models of daily foraging routines, that a bird will attempt to reach this level at dusk, regardless of its fat reserves the previous dawn. I provided supplementary food to manipulate the fat reserves at dawn of free-living European robins, Erithacus rubecula. Diurnal changes in body mass (a reliable estimate of fat reserves) were then monitored remotely. Robins provided with an ad libitum food supply reached almost exactly the same body mass at dusk, regardless of their body mass at dawn, supporting the prediction that birds attempt to reach a target level of reserves at dusk. Copyright 2000 The Association for the Study of Animal Behaviour.
随机动态规划（SDP）是一种计算技术，已被用于模拟小型鸟类的日常觅食行为。昼行性鸟类必须在黄昏时分积累脂肪储备，以避免在夜间无法觅食时挨饿。然而，除了避免饥饿的好处外，储存脂肪也会带来成本，比如被捕食风险增加以及飞行和代谢成本升高。因此，为了在夜间存活且黎明时不会留下过多脂肪储备，鸟类在黄昏时存在一个最佳脂肪储备水平。我测试了所有日常觅食行为的随机动态规划模型共有的一个预测，即无论鸟类前一个黎明时的脂肪储备如何，它都会试图在黄昏时达到这个水平。我提供补充食物来控制自由生活的欧洲知更鸟（欧亚鸲）黎明时的脂肪储备。然后远程监测体重（脂肪储备的可靠估计值）的昼夜变化。无论黎明时的体重如何，自由采食的知更鸟在黄昏时几乎达到相同的体重，这支持了鸟类试图在黄昏时达到目标储备水平的预测。版权所有2000动物行为研究协会。
