The term SAT ON A PERCH can be summarized as 'ROOSTED, ' which is a seven-letter word. Roosting is a behavior exhibited by birds, where they perch on a branch or other elevated surface to rest or sleep. Roosting is also used by some species of bats, who hang upside down from branches or other surfaces. Roosting is an important part of a bird's life cycle, as it provides them with a safe place to rest and sleep.