Estrogen, when present in early embryonic development, regulates sexual differentiation in the avian nestling and adult. In this study, I developed a procedure to extract and quantify levels (by radioimmunoassay) of the estrogen, 17[beta]-estradiol, in house wren (Troglodytes aedon) egg yolk. Levels of 17[beta]-estradiol found in one clutch of eggs increased with the order of laying, indicating female house wrens may be capable of regulating the levels of 17[beta]-estradiol received by the offspring. Since the attraction of mates is often aided by the display of sex differences, maternal control of 17[beta]-estradiol levels in the embryo may influence the future reproductive success of her offspring.
Waggoner '96, V. Brook, "Estrogen Levels in House Wren (Troglodytes aedon) Egg Yolks" (1996). Honors Projects. 21.