A songbird is a bird that can make musical sounds — a bird that sings rather than just squawks or croaks. Robins, blackbirds, nightingales, canaries and sparrows are songbirds. In everyday English that is all the word means, and people use it warmly: songbirds are the small pleasant birds in your garden at dawn. Scientists use it more narrowly, for a very large group of birds (about half of all bird species) whose throats are built for complex sound, and some birds in that group — crows, for instance — count as songbirds to a scientist even though nobody enjoys their singing. Two more honest details. First, in most species it is the male that sings, and he is usually not singing from happiness; he is claiming territory or looking for a mate. Second, the word gets used for people, almost always for a woman with a beautiful singing voice — 'the songbird of her generation'. That use is affectionate but old-fashioned now, and some people find it a bit sweet or patronising when applied to a grown professional singer.