The voices of spring
26 March 2007
During the spring and early summer, it's not just the milk van that will wake you early - it's dawn chorus time again.
From March to July, those feathered alarm clocks are at it again, as they defend their territories and sing to attract a mate.
Springing into song
Our songbirds time their breeding season to the warmest part of the year, when there is plenty of food and lots of daylight in which to find it. As winter turns to spring, the lengthening daylight switches male songbirds into breeding mode.
The first songsters of the season are residents such as robins and great tits, joined later on by migrants like chiffchaffs and blackcaps to make May and June the peak time to enjoy the dawn chorus.
The early bird gets the worm
The first birds begin to sing about an hour before sunrise. If you listen carefully, you may notice that there is a regular sequence, with some species habitually starting before others. Among the earliest to rise are skylarks, song thrushes, robins and blackbirds, and as they do eat worms there may be some truth to the old saying!
A more relaxed approach is taken by wrens and warblers, that typically appear later. These smaller birds, who are perhaps more sensitive to the coldness of dawn, feed on insects that themselves appear later in the morning.
The truth dawns
The dim light of dawn is not a good time to go foraging. Food, like insects and seeds, may be difficult to find, so perhaps it's a better time to try and attract a mate. Singing also brings the risk of attracting a predator, so it is better done before the bright morning light betrays the singer's position.
The lengthening daylight switches male songbirds into breeding mode
The air is often still at this time and, with less background noise, song can carry up to 20 times as far. As the light strengthens food becomes easier to find, so hungry birds begin to move off and the chorus gradually diminishes.
There is another chorus at dusk, which is considered quieter, though some birds - like tree sparrows and blue tits – seem to prefer to sing at this time of day. It may simply be that we take less notice of it than the dawn chorus, when we are so keen to enjoy a few more moments in bed!
He who sings last...
Singing is hard work, and uses hard won food reserves, so it is the fittest, best-fed males who produce the strongest, most impressive song. Females therefore choose a mate who sings best, because such a male is more likely to be good at raising chicks, to have a good territory, or to pass successful genes to their young.
In many species, once the female has been attracted, the male will sing less often. A bird that sings on and on, late into the season, is probably a lonely batchelor who has failed to attract a mate.
Enjoying your dawn chorus
If you want to listen to a dawn chorus, then the best days to choose are those with fine, clear weather and little wind. It can be cold early in the day, so remember to take warm clothes. Late April through to early June is the best period, when most species are singing well.
Dawn chorus peaks half-an-hour before to half-an-hour after sunrise, but the variety of song can prove too confusing at that time, so why not get into position a good hour before sunrise, and enjoy the arrival of the performers as each takes their turn on stage.
Want to learn more?
We're running dawn chorus guided walks at our reserves across the country in April and May (often with breakfast included). Visit our events page to find out what's going on near you.