1365-2656/asset/olbannerleft.gif?v=1&s=4f0919eca9042f833d018453e8f48b1e3e3123ec)
1365-2656/asset/olbannerright.gif?v=1&s=92164cf20561f2dc5785bff8431569e5b40f87aa)
You have full text access to this OnlineOpen article
Age at first breeding and fitness in goshawk Accipiter gentilis
Article first published online: 19 JAN 2005
DOI: 10.1111/j.1365-2656.2005.00920.x
Additional Information
How to Cite
KRÜGER, O. (2005), Age at first breeding and fitness in goshawk Accipiter gentilis. Journal of Animal Ecology, 74: 266–273. doi: 10.1111/j.1365-2656.2005.00920.x
Publication History
- Issue published online: 19 JAN 2005
- Article first published online: 19 JAN 2005
- Received 12 March 2004; accepted 30 July 2004
- Abstract
- Article
- References
- Cited By
Keywords:
- delayed maturity;
- fitness;
- life-history evolution;
- selection;
- territory quality
Summary
- 1Age at first breeding has a large influence on fitness and hence is crucial to the evolution of life-history strategies. Goshawks Accipiter gentilis start breeding aged 1–4 years. Using 30 years of data and both lifetime reproductive success (LRS) and lind as a fitness estimate for 74 female goshawks, I showed that the optimal age at first reproduction was 3 years in this population.
- 2Females that started to breed earlier had lower LRS and lind, not because of reduced life span, but because of lower reproduction at early ages.
- 3The constraint hypothesis, which states that foraging or other skills improve with age was the most likely explanation for the higher reproduction with increasing age.
- 4Incorporating habitat heterogeneity provided the mechanism that explained not only the fitness cost to early maturity, but also why this cost was heterogeneous. Females starting to breed aged 1 suffered a very high fitness cost if they were in a bad-quality territory, but fitness costs were small when they were in a good-quality territory. This explains why I found evidence for a nonlinear selection pressure on age at first breeding.
- 5Population density also affected whether a female started to breed early or not: over the study period, population density increased and the percentage of females starting to breed aged 1 decreased.
- 6The optimal age at first breeding seems to be a trait affected by a complex interplay between cost and benefits of early reproduction mediated by habitat heterogeneity and population density.