FACTORS INFLUENCING FOOD-LOAD SIZES BROUGHT IN BY SHAGS PHALACROCORAX-ARISTOTELIS DURING CHICK REARING
FACTORS INFLUENCING FOOD-LOAD SIZES BROUGHT IN BY SHAGS PHALACROCORAX-ARISTOTELIS DURING CHICK REARING
复制标题
DOI：
10.1111/j.1474-919x.1993.tb02805.x
复制
发表时间：
1993-01-01
期刊：
影响因子：
2.1
通讯作者：
RUSSELL, AF
中科院分区：
文献类型：
--
作者：
WANLESS, S;HARRIS, MP;RUSSELL, AF
用水卸载法测定了26只星冠黄羽雏鸟带回群体的食物负荷量。货物几乎全部由较小的沙丁鱼组成。负荷量变化极大，从8到208克不等，平均负荷量为106克。同时收集的觅食行为数据表明，当它们在离群体更远的地方取食时，当幼鸟的生物量较大时，它们会带回更重的负荷。这两个变量加在一起解释了负载大小变化的70.3%。我们推测，当成虫回到巢中时，它们已经消化了自己的食物需求，因此食物中的食物主要是为幼鸟准备的。在67%的航行中，沙格人平均每次潜水都会捕到一条以上的鱼。这一估计忽略了成鱼的食物需求，因此真实的猎物捕获率肯定更高。
Weights of food loads brought back to the colony by 26 Shags Phalacrocorax aristotelis rearing chicks were determined using the water-offloading procedure. Loads consisted almost entirely of lesser sandeels Ammodytes marinus. Load size was extremely variable, ranging from 8 to 208 g with a mean load weight of 106 g. Data on foraging behaviour collected concurrently demonstrated that Shags brought back heavier loads when they were feeding farther away from the colony and when brood biomass was larger. These two variables together explained 70.3% of the variation in load size. We postulate that adults had already digested their own food requirements by the time they arrived back at the nest, and the contents of the loads were therefore primarily for the young. On 67% of trips, Shags caught, on average, more than one fish per dive. This estimate ignores the food requirements of the adult, and therefore true prey-capture rates must have been higher.