Robins forced to sing at night to beat traffic noise

Urban birds have taken to singing at night because it is too noisy for their melodies to be heard during the daytime, researchers claim.

A study of robins in and around Sheffield found that birds nesting in areas that are noisy by day were more likely to sing at night than birds in quieter neighbourhoods. The researchers believe the birds have adapted the times at which they sing to be heard above the din of the city.

The report adds to growing evidence that birds are altering their behaviour to cope with modern life. Last year, scientist revealed that city-dwelling great tits had developed a high-pitched staccato song to attract their mates, while their country cousins adopted a slower and longer twitter. The same year, another group found that American robins began their dawn chorus earlier in areas with lots of streetlamps and other artificial lighting.

In the latest study, researchers at Sheffield University recorded sound levels at 121 sites across the city and beyond between April and June in 2005 and 2006. They heard robins singing during the day at 67 sites, and nocturnally at 18.