Migratory and resident Blackcaps Sylvia atricapilla wintering in southern Spain show no resource partitioning
Migratory and resident Blackcaps Sylvia atricapilla wintering in southern Spain show no resource partitioning
复制标题
在西班牙南部越冬的迁徙和留鸟黑帽西尔维亚·阿特里卡皮拉（Blackcaps Sylvia atricapilla）没有表现出资源分配
DOI：
--
复制
发表时间：
2013
期刊：
影响因子：
--
通讯作者：
J. Pérez‐Tris
中科院分区：
文献类型：
--
作者：
J. Tellería;M. Blazquez;I. Hera;J. Pérez‐Tris
当同一种鸟类的不同种群共享非繁殖地时，对食物的竞争可能会促进资源分配。我们研究了西班牙南部同域越冬地居住和迁徙的黑帽西尔维娅的食物选择。常驻黑头莺的喙更大，这可能使它们能够以更大范围的水果为食，而且它们可能比候鸟更了解食物的分布。基于水果和鸟类数量，我们将水果产量和鸟类数量转换为共同的能源货币。在果实产量低和高的两个冬季，估计1月中旬果实的可利用能量分别是黑头虱日需要量的80倍和1300倍。此外，在连续10年的监测中，黑帽的数量并没有追踪到冬季之间水果丰度的变化，这进一步表明水果食物并没有限制。对717个人的760个样本的食物分析表明，移民和居民主要以野生橄榄（Olea europaea sylvestris）的果实为食，这是最具活力的水果资源。没有证据表明居住的黑头莺的大喙提供了任何觅食的好处。迁徙的黑帽以野橄榄和无脊椎动物为食，这两种资源具有较高的能量和结构价值，比居民更频繁。这种食物选择对迁徙的黑头莺来说可能更重要，因为它们的体重较低，可以减少翅膀的负荷。我们的研究结果表明，伊比利亚黑帽的越冬地为同域迁徙者和居民提供了丰富的食物，没有资源分配。食物选择上的细微差异表明，移民可能会比居民吃更有营养的食物，以抵消体型较小带来的能量限制。
When different populations of the same bird species share non-breeding habitats, competition for food may promote resource partitioning. We studied food choice by resident and migratory Blackcaps Sylvia atricapilla in sympatric wintering grounds in southern Spain. Resident Blackcaps have a larger bill, which may allow them to feed on a broader range of fruit sizes, and they may know the distribution of food better than do migrants. Based on fruit and bird counts, we transformed both fruit crop and bird abundance to a common energy currency. During two winters with low and high fruit production, available energy from fruit in mid-January was estimated to be 80 and 1300 times, respectively, the daily requirements of Blackcaps. Furthermore, Blackcap numbers did not track between-winter changes in fruit abundance during 10 consecutive years of monitoring, further suggesting that fruit food is not limiting. Analysis of food items from 760 samples of 717 individuals showed that migrants and residents fed primarily on fruits of Wild Olive Olea europaea sylvestris, the most energetic fruit resource. There was no evidence that the larger bills of resident Blackcaps provided any foraging benefit. Migratory Blackcaps fed on Wild Olives and invertebrates, two resources with high energetic and structural value, more frequently than did residents. This food choice could be more important for migratory Blackcaps because they have lower body mass to reduce wing load. Our results suggest that the wintering grounds of Blackcaps in Iberia provide abundant food that is used by sympatric migrants and residents without resource partitioning. Slight differences in food choice suggest that migrants might benefit from feeding on more nutritive food than residents to counteract the energetic constraints associated with a smaller body size.