Gorman M L
J Reprod Fertil. 1977 Mar;49(2):225-30. doi: 10.1530/jrf.0.0490225.
Eider ducks showed clear tidal and seasonal cycles of display when involved in pair-formation behaviour. Plasma androgen (testosterone and dihydrotestosterone) concentrations did not follow similar tidal cycles but there was a 4-fold increase of androgen in spring when rates of display increased 2-fold. There was no difference in androgen levels in blood samples taken from paired birds before and after coitus. Androgens therefore appear to be essential for the expression of sexual behaviour, but there is no apparent quantitative correlation between overt sexual activity and androgen concentrations.
绒鸭在进行配对行为时，表现出明显的潮汐和季节性展示周期。血浆雄激素（睾酮和双氢睾酮）浓度并未遵循类似的潮汐周期，但在春季，随着展示频率增加两倍，雄激素水平增加了四倍。交配前后从配对的鸟类采集的血样中雄激素水平没有差异。因此，雄激素似乎对性行为的表达至关重要，但明显的性活动与雄激素浓度之间没有明显的定量相关性。
