The science behind the dawn chorus, birdsong, and bird calls - Hearing the tweeting, chirping, singing, and general ruckus birds make each morning is a gift for all early risers (but less so for those of us who prefer to sleep in). The incredible cacophony of sound is called the dawn chorus, but why do birds do it? What are the sounds that birds make anyway? And why do they all sound so different?
What’s the difference between bird song and bird calls?
Bird songs and calls aren’t the same thing. All birds call, but only some sing: songbirds – known as passerines – make up more than half of all bird species. Songs are generally more complex, consisting of several notes that are usually learned. A songbird may spend weeks listening and months practicing before they’ve perfected a particular song. Song is also usually for the purpose of mating – whether that be attracting a mate or marking territory against competition. On the other hand, calls are a single note. Sometimes they’re learned. For instance, a just-hatched baby bird is already capable of calling and begging for food. In some species, for example superb fairy wrens (Malurus cyaneus), the begging call is taught by the mother when the baby is still an embryo in the egg. In other species the begging call is innate.
Why do bird species sound so different to each other?
The sounds animals can make depend on the structures they have to make them. Humans have a larynx, whereas birds have a syrinx. The bigger the syrinx, the deeper a bird can sing – think of the range of a cello versus a violin. A common raven (Corvus corax) (which can weigh up to 2 kilograms) will produce sounds much lower than the golden-crowned kinglet (Regulus satrapa), a songbird that only weighs about 5.5 grams. Research also suggests that there might also be species specific sensory preferences: bird brains seem to influence bird song.
