The American study studied the song of American sparrows in urban areas and in the countryside before and after the corona crisis.

They compared the sounds of birdsong, the city and the countryside from five years ago with April, when the city closed down due to covid-19. 

They discovered that birds in urban areas communicated with a lower voice.

This despite the fact that they had twice as much distance from each other as five years ago.  

The birds that lived in the countryside, on the other hand, showed no major changes.

Thus, it was clear that the city birds had adapted to a new, quieter environment during the corona crisis.

The study is published in this week's Science. 

- They probably attract females from longer distances, says Anders Brodin, professor of theoretical ecology at Lund University. 

Customizable birds  

Should the lockdown continue, it means that they do not have to compete for living areas.

Hans sparrows would also make it easier to find a partner. 

But Anders Brodin doubts that the effects will be long-lasting.  

- I think it has huge effects but I do not think it has a genetic effect in such a short time.

If it were three or four years, it would surely have a genetic impact as well. 

This would mean that birds' genes adapt and that the behaviors remain.