Flight muscle atrophy and predation risk in breeding birds

摘要: 1. The speed with which small birds can get airborne is critical to the effectiveness of their escape response when attacked by a predator. However, take-off ability likely be affected physiological changes occurring as result egg formation. 2. To investigate whether reduced velocity cost reproduction, costs production in Zebra Finch (Taeniopygia guttata) were experimentally manipulated varying both number eggs female laid and quality her prelaying diet. The effect postlaying flight muscle condition body mass upon alarmed (a measure escape-ability birds) was subsequently measured. 3. Changes found correlate positively various measures velocity: treatments that caused greatest declines during egg-laying associated performance over this period. In contrast, breeding attempts smallest improvements (i.e. flew faster at end laying than start). 4. These effects independent mass, occurred postlaying, suggesting lies primarily formation eggs, rather carrying them other studies had suggested. observed trade-off between loss resulting from could have important implications for evolution optimal clutch size birds.