Recruitment and survival of immature seabirds in relation to oil spills and climate variability
Article first published online: 10 JUL 2008
© 2008 The Authors. Journal compilation © 2008 British Ecological Society
Journal of Animal Ecology
Volume 77, Issue 5, pages 974–983, September 2008
How to Cite
Votier, S. C., Birkhead, T. R., Oro, D., Trinder, M., Grantham, M. J., Clark, J. A., McCleery, R. H. and Hatchwell, B. J. (2008), Recruitment and survival of immature seabirds in relation to oil spills and climate variability. Journal of Animal Ecology, 77: 974–983. doi: 10.1111/j.1365-2656.2008.01421.x
- Issue published online: 13 AUG 2008
- Article first published online: 10 JUL 2008
- Received 17 January 2008; accepted 2 April 2008; Handling Editor: Henri Weimerskirsch
- oil pollution;
- population dynamics;
- sea surface temperature;
- 1In long-lived animals with delayed maturity, the non-breeding component of the population may play an important role in buffering the effects of stochastic mortality. Populations of colonial seabirds often consist of more than 50% non-breeders, yet because they spend much of their early life at sea, we understand little about their impact on the demographic process.
- 2Using multistate capture–mark–recapture techniques, we analyse a long-term data set of individually identifiable common guillemots, Uria aalge Pont., to assess factors influencing their immature survival and two-stage recruitment process.
- 3Analysis of the distribution of ringed common guillemots during the non-breeding season, separated by age classes, revealed that all age classes were potentially at risk from four major oil spills. However, the youngest age class (0–3 years) were far more widely spread than birds 4–6 years old, which were more widely spread than birds aged 6 and over. Therefore the chance of encountering an oil spill was age-dependent.
- 4A 2-year compound survival estimate for juvenile guillemots was weakly negatively correlated with winter sea-surface temperature, but was not influenced by oil spills. Non-breeder survival did not vary significantly over time.
- 5In years following four oil spills, juvenile recruitment was almost double the value in non-oil-spill years. Recent work from Skomer Island showed a doubling of adult mortality associated with major oil spills, which probably reduced competition at the breeding colony, allowing increased immature recruitment to compensate for these losses. We discuss the implications of compensatory recruitment for assessing the impact of oil pollution incidents.