A bird in the hand is worth two in the bush is a commonly used phrase, but one that never really made sense to me until I looked it up. Basically, it means things we already possess have value than the things we hope to acquire. Don't chase the new when what you have will do--and it's less risky as well. Apparently this phrase came into usage in the 15th century.
But, what is the bird in the hand?
It turns out that the bird in the hand is a falcon or hawk used for hunting. A hunting bird would certainly be more valuable than any prey that it catches. Fascinating!