Meeting Abstract
Estrogen has a number of organizational and activational effects in birds. Female birds require estrogen for reproductive anatomy development. During adulthood, male and female courtship and reproductive behaviors are associated with the presence of estrogen as well. Even at low concentrations, hormones can have organizational and activational effects; therefore, exposure to exogenous estrogens can cause significant changes in physiology and behavior. 17α Ethinylestradiol (EE2), the synthetic estrogen in birth control pills, is found ubiquitously in wastewater effluents. Previous research has primarily addressed the organizational effects of EE2 exposure during embryonic development in birds, not the activational effects during adulthood. We tested the potential for EE2 to disrupt the courtship behavior of adult zebra finches (Taeniopygia guttata). Adults were divided among treatment groups (control, 0.03, 4 or 100 ng EE2) and orally dosed every other day for 3 weeks prior to courtship trials. Interactions between newly paired males and females were then recorded for 20 minutes. One day after courtship trials, nest boxes and nesting material were provided to the pair. Boxes were checked every day to monitor nest building, egg laying, incubation behavior, and hatching. To quantify growth rates, offspring were measured on days 5, 10, 17, 28, 36 and 50 post hatch. Adults were dosed up until nestlings hatched. Overall, EE2 treated males made fewer mounting attempts than control males. However, males treated with 4 ng of EE2 produced more offspring than control males. Control females produced more offspring than treated females, however this difference was not significant. These findings strongly suggest that EE2 exposure in adulthood influences courtship behavior and reproductive success.
