Laboratory of Applied Ecology, CITAB, Centre for the Research and Technology of Agro-Environment and Biological Sciences, University of Trás-os-Montes e Alto Douro, 5000-911, Vila Real, Portugal.
Department of Life Sciences, MARE, Marine and Environmental Sciences Centre, University of Coimbra, 3004-517, Coimbra, Portugal.
Anim Cogn. 2020 Jul;23(4):629-642. doi: 10.1007/s10071-020-01368-1. Epub 2020 Mar 9.
Oceans are extremely dynamic environments, which poses challenges for top-predators such as seabirds to find food resources. Yet, seabirds evolved sensorial abilities (olfactory senses) along with complex behaviours (social information transfer through local enhancement) to improve foraging efficiency. Using the Cory's shearwater (Calonectris borealis) as a model species, we developed an individual-based model to explore the complementary role of different searching mechanisms (olfactory foraging and local enhancement) for the optimal foraging behaviour of pelagic seabirds during 1-day foraging trips around breeding colonies. Model outputs were compared with observed patterns of Cory's shearwaters distribution during local foraging trips. Also, the foraging efficiency of virtual individuals was analysed considering hypothetical scenarios of foraging conditions and densities of foraging individuals around breeding colonies. The results support the use of a combination of searching strategies by Cory's shearwaters, which produced representative patterns of space use from tracked individuals, including spatial foraging segregation of neighbouring sub-colonies. Furthermore, while the mechanisms underpinning local enhancement played a key role in mitigating sub-optimal foraging conditions, the use of olfactory senses conferred great adaptive foraging advantages over a wide range of environmental conditions. Our results also indicate a synergistic effect between the two strategies, which suggests that a multimodal foraging strategy is useful to forage in extremely dynamic environments. The developed model provides a basis for further investigation regarding the role of foraging mechanisms in the population dynamics of colonial animals, including the adaptive foraging behaviour of marine top predators to dynamic environmental conditions.
海洋是极其动态的环境，这给像海鸟这样的顶级捕食者寻找食物资源带来了挑战。然而，海鸟进化出了感官能力（嗅觉）和复杂的行为（通过本地增强的社会信息传递），以提高觅食效率。我们使用冠毛海雀（Calonectris borealis）作为模型物种，开发了一个基于个体的模型，以探索不同搜索机制（嗅觉觅食和本地增强）在海鸟进行 1 天觅食旅行时对最佳觅食行为的补充作用，这些觅食旅行围绕繁殖地进行。模型输出与冠毛海雀在本地觅食旅行中观察到的分布模式进行了比较。此外，还考虑了繁殖地周围觅食个体的觅食条件和密度的假设情景，分析了虚拟个体的觅食效率。结果支持了冠毛海雀组合使用搜索策略，这从跟踪个体中产生了具有代表性的空间利用模式，包括相邻亚群之间的空间觅食隔离。此外，虽然支持本地增强的机制在缓解次优觅食条件方面发挥了关键作用，但嗅觉的使用在广泛的环境条件下赋予了适应性觅食的巨大优势。我们的结果还表明，两种策略之间存在协同作用，这表明多模态觅食策略对于在极其动态的环境中觅食很有用。所开发的模型为进一步研究觅食机制在群居动物的种群动态中的作用提供了基础，包括海洋顶级捕食者对动态环境条件的适应性觅食行为。
