The term 'of songbirds' can be summarized by the crossword solution 'OSCINE, ' which is a six-letter word. Oscines are a suborder of passerine birds, which are also known as perching birds or songbirds. They are distinguished from other passerines by their vocal organ, which is highly developed and allows them to produce complex songs. Oscines are found in many parts of the world and include species such as sparrows, finches, and crows.