Present address: Institut Méditerranéen d’Ecologie et de Paléoécologie, Université Paul Cézanne d’Aix-Marseille, Europôle de l’Arbois, 13545 Aix-en-Provence Cedex 04, France.
Natal conditions alter age-specific reproduction but not survival or senescence in a long-lived bird of prey
Article first published online: 6 APR 2011
© 2011 The Authors. Journal of Animal Ecology © 2011 British Ecological Society
Journal of Animal Ecology
Volume 80, Issue 5, pages 968–975, September 2011
How to Cite
Millon, A., Petty, S. J., Little, B. and Lambin, X. (2011), Natal conditions alter age-specific reproduction but not survival or senescence in a long-lived bird of prey. Journal of Animal Ecology, 80: 968–975. doi: 10.1111/j.1365-2656.2011.01842.x
- Issue published online: 26 JUL 2011
- Article first published online: 6 APR 2011
- Received 28 September 2010; accepted 10 March 2011 Handling Editor: Dan Nussey
- cyclic prey dynamics;
- field vole;
- life-history optima;
- natal environment effect;
- tawny owl
1. Natal conditions and senescence are two major factors shaping life-history traits of wild animals. However, such factors have rarely been investigated together, and it remains largely unknown whether they interact to affect age-specific performance.
2. We used 27 years of longitudinal data collected on tawny owls with estimates of prey density (field voles) from Kielder Forest (UK) to investigate how prey density at birth affects ageing patterns in reproduction and survival.
3. Natal conditions experienced by tawny owls, measured in terms of vole density, dramatically varied among cohorts and explained 87% of the deviance in first-year apparent survival (annual estimates ranging from 0·07 to 0·33).
4. We found evidence for senescence in survival for females as well as for males. Model-averaged estimates showed that adult survival probability declined linearly with age for females from age 1. In contrast, male survival probability, lower on average than for female, declined after a plateau at age 1–3.
5. We also found evidence for reproductive senescence (number of offspring). For females, reproductive performance increased until age 9 then declined. Males showed an earlier decline in reproductive performance with an onset of senescence at age 3.
6. Long-lasting effects of natal environmental conditions were sex specific. Female reproductive performance was substantially related to natal conditions (difference of 0·24 fledgling per breeding event between females born in the first or third quartile of vole density), whereas male performance was not. We found no evidence for tawny owls born in years with low prey density having accelerated rates of senescence.
7. Our results, combined with previous findings, suggest the way natal environmental conditions affect senescence varies not only across species but also within species according to gender and the demographic trait considered.