idioms

have heart in mouth  informal (to be extremely excited or nervous) I had my heart in my mouth when the plane was about to take off. He was waiting for the exam result with his heart in his mouth.     – English Vocabulary

birds of a feather (people who are alike in character or interests) Mia and Ethan seem to get along pretty well. They’re birds of a feather. Recent studies show that people who are birds of a feather make better marriages than those who are not.   – English Vocabulary

  birds and the bees (the fact about sex and reproduction) Some parents never tell their children about the birds and the bees. I will tell you all about the birds and the bees tomorrow.     – English Vocabulary

bird has flown (the person you are looking for has escaped or disappeared) I don’t think you can find him here. The bird has flown. The police surrounded the area in the middle of the night, but the bird had flown.     – English Vocabulary

big fish in a small pond (an important person in a small group or organization) In our company, Doctor Gomez is a big fish in a small pond. (someone who is important but only in a small group or organization) Colin was a big fish in a small pond here, …