Meeting Abstract

P1.5A  Tuesday, Jan. 4  Egg colour in European starlings: relationship with female quality, male parental effort and haematology. FRONSTIN, Raime/B*; DOUCET, Stephanie/M; WILLIAMS, Tony/D; Simon Fraser University; University of Windsor; Simon Fraser University rbf1@sfu.ca

The function of variation in eggshell colour remains very poorly understood in birds. It has been proposed that blue-green egg coloration might function as a sexually-selected, condition- dependent signal of female quality, which males might then use to determine their level of post- hatching parental investment. We tested this hypothesis in European starlings (Sturnus vulgaris) by relating variation in egg-colour to variation in female condition, laying date and clutch size (known predictors of female fitness), and to male provisioning effort and breeding success (brood size and chick mass at fledging). Blue-green chroma (the measure indicative of biliverdin content in eggshells) increased with egg-laying sequence and was positively correlated with female post-laying body mass (r = 0.33) but laying date, clutch size and egg mass were independent of BGC. The variable blue-green to white coloration of starling eggs is due to the pigment biliverdin which is formed through degradation of haem in the liver. Although it is not clear to what extent biliverdin is derived from breakdown of red blood cells during shell formation, we speculated that individual variation in egg colour might be related to variation in haematological parameters (hematocrit and haemoglobin levels) and reproductive ‘anemia’ associated with egg production in females. We test this idea using an experimental perturbation of hematocrit (with the drug phenylhydrazine which causes haemolytic anemia) comparing egg colour in non-manipulated first clutches and replacement laid after PHZ treatment in relation to changes in plasma hematocrit and haemoglobin levels.