OPTIMIZING FAT RESERVES OVER THE ENTIRE WINTER - A DYNAMIC-MODEL

被引:70
作者
BEDNEKOFF, PA [1 ]
HOUSTON, AI [1 ]
机构
[1] UNIV OXFORD, DEPT ZOOL, NERC, BEHAV ECOL UNIT, OXFORD OX1 3PS, ENGLAND
关键词
D O I
10.2307/3545828
中图分类号
Q14 [生态学(生物生态学)];
学科分类号
071012 ; 0713 ;
摘要
During winter, energetic expenditure is high, days are short, and food is often scarce. Many small birds cope with winter weather by daily depositing fat reserves approximately equal to the amount of energy they will. expend the following night. We modelled fat reserve levels for small birds over a 100-day winter. We assumed that: a) Expected energetic requirement was greatest in midwinter, mimicking long, cold nights. b) Energetic requirement varied around the expected value. c) Food was always available but feeding entailed a predation hazard. We found the following: 1) Under all sets of parameters tested, fat reserve levels through the winter rose and fell with energetic requirement. 2) Optimal fat levers were higher with increased Variance in energetic requirement. 3) Predation had virtually no effect on reserve levels unless heavier birds were more at risk, although it had a strong impact on survival rates. 4) The direction of change in requirement and alternative end-of-winter ecological scenarios had little effect on reserve levers. Our results suggest that a small bird should regulate its fat reserves taking into account energetic requirement, environmental variability, and the relationship between mass and predation risk.
引用
收藏
页码:408 / 415
页数:8
相关论文
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