Feelings of love could help to keep them happy and content to face the challenges of child rearing .

爱的感觉会帮助它们保持快乐并愿意去面对养育幼鸟带来的困难。

Both take turns incubating their single egg and defending the nest , and both share duties in rearing the hatchling .

它们轮流孵化唯一的卵，共同保卫它们的巢穴，共同承担抚养孵化小鸟的责任。

Here he began an intensive strategy of egg-collecting , captive rearing in the bronx zoo , and release .

于是他在此开始了一项十分细致的扬子鳄蛋收集行动，然后在布朗克斯动物园人工饲养，再放归大自然。

This involves crop rotation and the rearing of " free-range " livestock which are not force-fed hormones or antibiotics .

这包括到轮作与养育“自由牧场”的牲畜，它们都没有被迫食用激素或抗生素。

Over the course of evolution , it was rare for our maternal ancestors to be full-time mothers , said brizendine , because there was always kin-folk around to help with child rearing .

在历史的演化过程中，我们的母性祖先做个全职妈妈是很罕见的，布里曾丹说，因为他们身边总有亲朋好友来帮助养育儿女。