What is the origin of the idiom "a bird in the hand" and when to use it?

The phrase is believed to have originated from the practice of bird hunting, where a hunter might be tempted to release a bird they have caught in the hope of catching two more. However, by releasing the bird, the hunter risks losing the one they have already caught, while the two in the bush may be hard to catch. It is commonly used to advise caution and to suggest that it is better to be content with what one has than to risk losing it by pursuing something that is uncertain or has a higher potential reward.