What is the origin of the idiom "for the birds" and when to use it?

The idiom "for the birds" likely originated in the United States during the early 20th century, though its exact source remains uncertain. This expression is used to convey the notion that something is unimportant, trivial, or of little value, comparable to matters that only birds would find meaningful or interesting. It is a way to dismiss or deride a subject or situation as insignificant.