The Long-tailed Tit is usually heard before it is seen — the flock keeps together with a constant, eager babble of contact calls. The commonest sounds are a thin, grating "tsrii-tsrii-tsrii" and a short, rattling "tupp-tupp-tupp". The calls are the species' most reliable field mark, as the tiny birds often move about hidden in the branches. There is no real song; instead, a subdued mix of the same grating and rattling notes is heard during the breeding season.