Until genetic analysis became cheap enough for ornithologists4 to employ routinely, it was believed that this monogamy implied fidelity5, and that the nestlings6 fed so assiduously7 by the male in such a partnership were, indeed, his.

• 在基因分析变得很便宜使鸟类学家能经常采用之前，人们一直相信，一雄一雌配对意味着忠诚，并且这样配对的雄鸟如此勤奋喂养的雏鸟当然是自己的后代。