This usually happens in hand-feeding birds that are either continuously overfed or hand-fed long after they should have been weaned.
这通常发生在手喂食鸟类，要么不断吃得太多或手喂食后不久，他们应该已经断奶。
2
Elk and bears regularly walk underneath, and the visitor book is filled with stories of feeding squirrels and birds by hand.
树林里常有麋鹿和熊出没，旅客留言簿里记满了亲手为松树和鸟儿喂食的故事。
3
I have to reinforce that after a trip to the mall yesterday. I saw one mom feeding her baby, who was in a stroller, a bottle with one hand while talking on her cell phone with the other.