PATTERNS OF VARIATION IN SIZE AND COMPOSITION OF GREATER SCAUP EGGS: ARE THEY RELATED?

摘要: We studied egg size variation of Greater Scaup (Aythya marila) nesting on the Yukon-Kus- kokwim Delta, Alaska from 1991-1996. Mean was 64.36 ? 0.03 (SE) ml. Egg did not vary with clutch or serve as an index body size. There less than 2% overlap in total volumes for clutches different sizes indicating that phenotypic size-egg trade-offs are occurring among individuals. At population level, have other species waterfowl. The proportion caused by differences females 0.20, within years 0.25, and (i.e., clutches) 0.56. lipid decreased increasing while protein increased Thus, appear to trade-off increases. due 0.79 0.49. conclude absence a fitness between size, selection has reduced among-individual Received 16 April 1999, accepted 4 August 1999.