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Survival benefits of post-fledging care: experimental approach to a critical part of avian reproductive strategies
Article first published online: 5 JAN 2010
DOI: 10.1111/j.1365-2656.2009.01650.x
© 2010 The Authors. Journal compilation © 2010 British Ecological Society
Additional Information
How to Cite
Grüebler, M. U. and Naef-Daenzer, B. (2010), Survival benefits of post-fledging care: experimental approach to a critical part of avian reproductive strategies. Journal of Animal Ecology, 79: 334–341. doi: 10.1111/j.1365-2656.2009.01650.x
Publication History
- Issue published online: 5 FEB 2010
- Article first published online: 5 JAN 2010
- Received 25 June 2009; accepted 2 December 2009 Handling Editor: Jonathan Wright
- Abstract
- Article
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- Cited By
Keywords:
- avian life history;
- juvenile survival;
- parental care;
- post-fledging period;
- reproductive effort
Summary
1. Caring for offspring beyond leaving the nest is an important but under-studied part of avian life histories. Theory predicts that prolonged post-fledging parental care should yield fitness benefits such as increased fledgling survival. Post-fledging care is also costly in terms of time and energy available for subsequent reproduction, moult or migration. So far, direct measurements of the fitness effects of the duration of post-fledging parental care are lacking.
2. In a partial cross-fostering experiment, barn swallow (Hirundo rustica) chicks were exchanged among broods close to fledging. Thereby, we separated the effects of post-fledging care from those of pre-fledging origin on juvenile survival.
3. Prolonging post-fledging care substantially increased juvenile survival up to 3 weeks post-fledging. Juvenile mortality was maximal in the days following the termination of parental care, and prolonging care delayed and reduced this peak mortality. Survival of fledglings experiencing 6 days of care was Φ = 0·227, whereas fledglings experiencing 14 days of care showed a survival of Φ = 0·571.
4. Offspring from pairs providing short care showed lower post-fledging survival than did offspring from pairs providing long care, irrespective of the actual duration of care experienced. This gives evidence for an additional survival effect of pre-fledging factors associated with the parental duration of care.
5. The results suggest that differential survival in relation to post-fledging parental care is a major fitness component. This relationship has profound effects on the reproductive trade-offs underlying the evolution of avian life histories.