A new method to quantify prey acquisition in diving seabirds using wing stroke frequency
A new method to quantify prey acquisition in diving seabirds using wing stroke frequency
复制标题
DOI：
10.1242/jeb.009811
复制
发表时间：
2008-01-01
影响因子：
2.8
通讯作者：
Wanless, Sarah
中科院分区：
文献类型：
--
作者：
Sato, Katsufumi;Daunt, Francis;Wanless, Sarah
为了了解自由潜水动物的觅食策略，关于觅食努力和觅食成功的时间序列信息是必不可少的。理论表明，在较重的鸟类身上，空中飞行的机翼击打频率应该更高。基于这一前提，我们开发了一种新的方法，使用动物携带的加速度计来估计追逐-潜水、食鱼的海鸟-欧洲海鸟Phalacrocorax aristotelis的身体质量的精细时间变化。我们假设，根据一系列潜水前后翅膀击打频率的变化确定的体重变化将与捕获的猎物的数量有关。在一次觅食之旅中，估计的体重净增量变化很大，从-30克到260克不等，这个值与前几年使用水卸载和巢穴平衡从五月岛上的粪便获得的食物负荷非常相似。使用机翼冲程方法估计的载荷大小与累积飞行时间和返回飞行时间都呈强烈的正相关。在行程水平上，负荷量大小与累计潜水持续时间和水下总时间无关。然而，在个人比赛层面上，高度显著的关系是显而易见的，鸟类在更长的跳水比赛中表现出更大的质量收益。因此，这项研究的结果非常令人鼓舞，并表明，根据翅膀击打频率的变化确定的体重变化可能提供一种可靠的方法，获得关于潜水海鸟觅食努力和成功的中短期信息。
To understand the foraging strategies of free-ranging diving animals, time series information on both foraging effort and foraging success is essential. Theory suggests that wing stroke frequency for aerial flight should be higher in heavier birds. Based on this premise, we developed a new methodology using animal-borne accelerometers to estimate fine-scale temporal changes in body mass of a pursuit-diving, piscivorous seabird, the European shag, Phalacrocorax aristotelis. We hypothesized that variations in body mass determined from changes in wing stroke frequency before and after a series of dives would be related to the amount of prey captured. The estimated net gain in body mass during a foraging trip was highly variable, ranging from -30 to 260 g, values that were extremely similar to food loads obtained from shags on the Isle of May in previous years using water-offloading and nest balances. Load sizes estimated using the wing stroke method were strongly and positively related to both cumulative flight time and return flight time. At the trip level, load size was unrelated to cumulative dive bout duration and the total amount of time spent underwater. However, highly significant relationships were apparent at the individual bout level, with birds showing bigger mass gains following longer dive bouts. Results from this study are therefore extremely encouraging and suggest that changes in body mass determined from changes in wing stroke frequency may provide a reliable method of obtaining short- to medium-term information on foraging effort and success of diving seabirds.