||David Ward, Do Polyandrous Shorebirds Trade off Egg Size with Egg Number? Journal of Avian Biology, Vol. 31, No. 4 (Dec., 2000), pp. 473-478 link p.473 left column
||Emlen, S. T. and Oring, L. W. 1977. Ecology, sexual selection, and the evolution of mating systems. - Science 197: 215- 223. AND Ligon, J. D. 1993. The role of phylogenetic history in the evolution of contemporary avian mating and parental care systems. - Curr. Ornithol. 10: 1-46. link PubMed ID327542
||P.473 left column: "Classical polyandry, in which one female mates with a number of males and each male has its own nest, is a rare form of mating system in birds, found in less than 1% of species (primary sources). It is possible that in those species where polyandry has evolved, selection has occurred for increased energetic efficiency of females to allow them to commit more energy to reproduction and thus overcome the increased cost of laying more eggs. However, because most organisms have a fixed amount of energy available for maintenance and reproduction, it is more likely that polyandrous females have to trade off allocating energy to many clutches against either the number of eggs per clutch or the size of eggs or both (Winkler and Walters 1983, primary source Ligon 1993)."