Why do birds all perform the "Dawn Chorus"?

Question

What could be the scientific reason?

Cinija - thanks that really helps do you always answer questions without thinking first?

Answer 1

Simply put, to mark and defend their territory. The birdsong is as much a battle hymn as a love song! It seems that individuals seeking territories are particularly active immediately after first light, for it is light enough to get about but not light enough to forage. It is, in any case, a cold time of day and the prey of the insect feeder is not yet active. So confrontations take place but once there is enough light to feed by, both challenger and challenged are presumably diverted by the need to satisfy their hunger. The dusk-chorus is a lesser event but there is a very noticeable increase in song each evening in the British spring, in my garden at least the song thrush seems to be particularly defensive at this time of day.

It is also true that songs carry much better around dawn and dusk because there is less wind at those times of day, not only is there tranquility, there is also much less background noise (natural and man-made). For these two reasons a typical bird song, it has been calculated, will carry 20 times as well as at noon.

Answer 2

Not all birds take part in the dawn chorus. Owls, nightjars and other nocturnal birds don't. Thinking about it most of the birds taking part are passerines. There would be few non-passerine birds that took part. Some cuckoos and pigeons do round here but not the parrots or raptors.

Answer 3

birds sing to denfend their territory and to attract mates.

Answer 4

to defend there homes