Sexual selection in the house sparrow
The isolated population of house sparrows on (Lundy Island) in the Bristol Channel has been the subject of an individual-based study since 1995.
The population has the advantage of having very low dispersal rates, allowing individuals and their offspring to be monitored to determine long-term survival. Microsatellite DNA profiling can be used to determine parentage and hence measure the reproductive success of each bird.
This study will investigate the evolution and maintenance of variation in the size of the black throat patch ("badge") of male sparrows. This badge is a sexually selected trait thought to act as an "honest signal" of quality, and may be used as a cue in both male-male competition and female choice.
Cross-fostering experiments on the Lundy population have shown that, contrary to expectation, the badge size of male offspring was significantly related to that of their foster fathers, but not to their genetic fathers.
Large-badged males were also found to have significantly higher survival than those with small badges, supporting the theory that the badge functions as a reliable indicator of quality. This project aims to confirm the generality of the earlier heritability result, and to elucidate the natural and sexual selective pressures that act upon this trait.
This study is funded by the Biotechnology and Biological Sciences Research Council.
Personnel
Nancy Ockendon (2000-2004)
Supervisor
Background references
Griffith SC. (2000) A trade-off between reproduction and a condition-dependent sexually selected ornament in the house sparrow, Passer domesticus. Proceedings of the Royal Society of London, Series B, 267, 1115-1120.
Griffith SC. (2000) High fidelity in island populations: a comparative study of extra-pair paternity in passerine birds. Behavioural Ecology, 11, 265-273.
Griffith SC, Owens IPF, Burke T. (1999) Female choice and annual reproductive success favour less-ornamented male house sparrows. Proceedings of the Royal Society, London, Series B, 266, 765-770.
Griffith SC, Owens IPF, Burke T. (1999) Environmental determination of a sexually selected trait. Nature, 400, 358-360.
Griffith SC, Stewart, IRK, Owens IPF, Dawson DA, Burke T. (1999) Contrasting levels of extra-pair paternity in mainland and island populations of the house sparrow (Passer domesticus): is there an 'island effect'? Biological Journal of the Linnean Society. 68, 303-316.