It is not just cliché, birds really do sing mostly – and most prominently – in the morning. But why do they sing at all?
Almost half of the world’s bird species are songbirds. Of course, all bird species make noises, but we differentiate between calls and songs. Calls are direct and sharp; they are short, simple noises. The song however can be two to six seconds long and are repeated over and over.
The first ones to starts as early as 4am are Blackbirds, Robins and Wrens. One of the theories around the early morning tweeting is that it is not yet bright enough to forage and there is therefore time for singing. In cities, the theory is that mornings are beneficial for birds because their songs travel further while they would be covered by urban noise. Their voices can travel in dense woodlands.
Early morning twitter storm
It is mainly males who sing. They attempt to attract mates and use their song as a warning to other males trying to invade their territory. So what we perceive as music are the mating rituals of the birds in our environment and every male has his own special song. Females fly through the area and listen out for a song they like. As singing takes strength, a loud song shows the male is strong and healthy. A female will then check if the male has desirable genes and explore his territory.
As the main aim of the twitters is to attract potential mates, birds mainly sing during breeding season. They will sit away from their nest in a high spot to scare away other males and consistently repeat their tones. Once the young are born, there is less time for singing as the fledglings have to fed and cared for.
Learning to sing
The fledglings will learn the songs from their parents; in the nest they memorise it as well as other songs in the area and slowly develop a ‘subsong’. As juveniles, they move away from the nest to find their own territory and practise the songs until they extend it into their own song. By the next spring, they are ready to breed and defend their territory.
While singing is about communication, birds seem more attractive if they have a larger repertoire; it is similar to humans being more interested in a mate who can hold up an interesting conservation rather than getting bored during the exchange. Some birds have just one song, such as House Sparrows, while for example Nightingales have a wide range of songs.
Songs are a language
Starlings and Jays mimic other birds or mechanised sounds. Blue Jays even mimic larger birds such as hawks to let others of their species know there is a hawk, a predator, around or as a defence mechanism to deceive others and let them believe a hawk is around.
In the UK it is mainly males singing. Some female singers robins and dotterels, but in tropical climates, males and females will sing duets.
Over time, local dialects emerge. Birds of the same species only need to be isolated on an island or habitats to be separated by a forest or other barrier and birds will take on a certain song which will be passed on to the young until songs of the same species sounds very different – just like in our languages.
So what we actually hear when we wake up to bird twitter is flirting, a little bit of conversation and males boasting to win females over.
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