When alone, a magpie may make a quiet musical warbling; these complex melodious warbles or subsongs are pitched at 2–4 KHz and do not carry for long distances. These songs have been recorded up to 70 minutes in duration and are more frequent after the end of the breeding season. Pairs of magpies often take up a loud musical calling known as "carolling" to advertise or defend their territory; one bird initiates the call with the second (and sometimes more) joining in. Often preceded by warbling, carolling is pitched between 6 and 8 kHz and has 4–5 elements with slurring indistinct noise in between. Birds will adopt a specific posture by tilting their heads back, expanding their chests, and moving their wings backwards. A group of magpies will sing a short repetitive version of carolling just before dawn ("dawn song"), and at twilight after sundown ("dusk song"), in winter and spring.