Dr Catherine M. Lessells, Netherlands Institute of Ecology, Heteren, Netherlands

The aim of this project is to investigate the three way interaction between maternal yolk hormones, chick begging behaviour and parental provisioning response in the great tit Parus major. In particular, this study will investigate: (A) the consequences of variation between clutches in the average level of maternal yolk hormones, (B) the genetic and environmental causes of variation between clutches in maternal yolk hormones, and (C) the genetic and environmental causes of relationships between chick begging behaviour and parental response. Genetic realtionships will be investigated by cross-fostering entire broods to remove maternal and paternal effects. Environmental relationships will be investigated initially from correlations between variables, and followed up as appropriate by experimental manipulations.