New research has discovered that excessive levels of noise around the sites where birds choose to nest could affect their chicks' chances of survival and, as a result, be impacting upon population levels.
A team of scientists from Dalhousie University in Nova Scotia knew that baby birds depend heavily on communications with their parents and the outside world to direct food their way and avoid predators, but they wanted to test whether this can be disrupted by noisy environments.
They therefore set up audio equipment near nests containing infant swallows and presented them with clips of their parents either announcing they were back with food or warning their offspring to be quiet because a predator was nearby.
Each clip was presented both in a quiet environment and with recorded background noise, whereupon the responses of the chicks were analysed.
It was found that background noise including traffic and building work reduced the baby birds' responses to both feeding calls and alarm calls. For example, they frequently continued begging when danger was present and sometimes missed opportunities to beg when food was available, putting themselves in danger of being killed or starving.
Presenting their findings at an annual conference in the US, the team warned that this demonstrates just how serious increasing urbanisation and development can be for birds' wellbeing and ultimately their future survival worldwide.
"We usually associate declines in animal populations with our physical destruction of habitat, but the noise we make is another threat that we can't ignore," said lead researcher Andy Horn.
Of course, British birds are not nesting at present, but this is an important study to bear in mind for the spring and when choosing sites for nesting boxes.
The breeding season begins in February for us and birds like to carefully investigate potential sites well in advance, so putting up a nest box like our El Paso style now could result in them taking shelter in it during the cold winter and then choosing it for breeding next year.
Given the study in Nova Scotia, it is likely to be a good idea to opt for somewhere as far from human noise as possible in order to maximise your chances of the box you erect being used in the spring. If you're not sure what box you need for particular species, check out our size guide here.