期刊
LIMNOLOGY AND OCEANOGRAPHY
卷 56, 期 3, 页码 802-812出版社
WILEY
DOI: 10.4319/lo.2011.56.3.0802
关键词
-
资金
- Natural Sciences and Engineering Research Council of Canada (NSERC)
- Research and Technology Centre in Busum
- Memorial University of Newfoundland
We report on inter-annual comparisons of the foraging behavior of Global Positioning System-equipped chick-rearing northern gannets (Morus bassanus) in the western Atlantic during years with contrasting oceanographic and prey conditions. We hypothesized that the predators would modify their foraging tactics when small fishes (capelin [Mallotus villosus]) and large pelagic fishes (mackerel, saury) varied in inter-annual abundances. We predicted differences in (1) diving behavior, (2) spatial, and (3) temporal patterning of foraging behavior. Predictions 1 and 2 were supported, prediction 3 rejected. Dives were significantly deeper (4.3 +/- 0.4 vs. 2.7 +/- 0.3 m) and longer (10.1 +/- 1.0 vs. 5.0 +/- 0.2 s), and more U-shaped dives (dives where birds stayed at more or less one depth) were performed (52% +/- 7% vs. 7% +/- 2%) in the year with higher abundance of forage fishes. Flight patterns exhibited remarkable spatial and geographic differences: gannets flew significantly (17%) more and foraging ranges were about twice as long when they pursued large pelagic fishes (mean = 122 +/- 81 km vs. 62 +/- 12 km). The 95% kernel feeding range was 34 times larger when large pelagic fishes were available. Yet foraging trip durations were not different between years. Inter-annual variation in foraging tactics by the same species at the same colony in successive years was strongly related to prey availability, showing that spatial foraging parameters can be determined largely by ocean and prey conditions.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据