Study of optimal foraging of diving seabirds with micro-time scale measurements of accceleration

在调整体重后，海鸟比海洋哺乳动物潜得更深，潜得更长。为了了解这种高潜水能力的生理和行为机制，进行了许多实验室研究。由于它必须在有限的氧气储存量的限制下进行水下觅食，因此它也是研究最佳觅食的良好材料。然而，由于能量消耗和食物摄入数据的收集困难，野外的实证研究还不够充分。我们测量了野生深潜海鸟的潜水行为和猎物追求的细节，以检验潜水的成本和收益。我们的具体目的是了解鸟类面对水中浮力和阻力时高潜水能力和捕食的机制。为了估算翅膀或脚掌划动、栖息地利用和猎物捕获的生物力学成本，我们将加速度记录数据记录仪和摄像机记录仪安装在alci…More ds和企鹅以及shag的背部。1)我们提出了一个假设，该假设平衡了增加冲程的成本和通过增加游泳速度减少过境时间的收益。研究发现：2)专业潜水员（海鸟和海洋哺乳动物）为了保持一定的游泳速度（2m/s），会以体重的幂函数（0.3）降低划水频率；3)飞潜海鸟在空中和水中的划水频率分别高于预期和低于预期；指适于飞行和游泳的一种有补偿的划水方式。此外，我们还提出了新的技术，通过测量潜水之间飞行期间短时间尺度（<10min）的翅膀拍击频率来估计每次觅食期间的食物摄取量；5)在底部觅食期间拍摄图像数据来估计微栖息地的利用和猎物的追捕。为了解海洋环境变化对海鸠觅食行为精细尺度调整的影响，研究了海鸠在白令海的潜水和觅食行为。研究发现：1)海鸠会根据温跃层的变化和猎物的垂直分布而改变潜水深度和觅食水质量；2)亲本觅食容易捕获小猎物、磷虾和0年明太鱼，但会潜入深海捕捉大鱼和1+明太鱼，以提高供给率。少

Seabirds are known to dive deeper and longer than marine mammals after body mass is adjusted. Many laboratory studies have been carried out to understand the physiological and behavioural mechanisms of this high diving ability. Since its underwater foraging has to be achieved under limitation of with the limited amount of oxygen store, it is also a good material of the study of optimal foraging. Empirical study in the wild, however, has bee insufficient because of the difficulties collecting data of energetic cost and food intake. We measured detail of diving bahaviour and prey pursuit in deep diving seabirds in the wild to examine the cost and benefit of diving. Our specific aim is to understand the mechanism of high diving ability and prey intake when the birds face with the buoyancy and the drag in the water. To estimate biomechanical cost of wing or foot stroke, habitat utilization, and prey capture, we attached acceleration recording data-loggers and camera-loggers on back of alci … More ds and a penguin, and shags. 1) We proposed a hypothesis that shags balance the cost of increasing stroke rate and the benefit of the reduction of transit time by increasing swim speed. We found that 2) specialist divers (seabirds and marine mammals) decrease the frequency of stroke with the power function of body mass (0.3) presumably to keep a range of swim speed (2m/s), and 3) flying-diving seabirds, however, had higher and lower stroke frequency in the air and water, respectively, than expected; indicating a compensated stroke pattern suitable for flying and swimming. Further, we proposed new techniques to estimate 4) food intake during a each foraging bout by measuring wing stroke frequency at short time scale (<10min) during the flight period between diving bouts and 5) micro habitat use and prey pursuit by taking image data while foraging during bottom phase. To understand the effects of marine environmental change on fine scale adjustment of foraging behaviour, we studied diving and foraging behaviour of guillemots in the Bering Sea. We found that 1) guillemots changed dive depth and foraging water masses in relation to the change of thermocline and resulting vertical distribution of prey, 2) parents forage easily collected small prey, krill and 0-year-pollack for themselves but dove deep to capture large fish and 1+ Pollack to increase provisioning rate. Less