Retired firefighter Bob Simpson of Crossgates says people try to prevent birds such as House Martins building their nests, by hanging plastic carrier bags out of upstairs windows.

He said: “It’s the time of year when House Martins start to build their nests mostly on the eves or gable ends of our homes.

“Judging by the amount of properties with plastic bags flying out of the windows as a deterrent they are obviously not always welcome. Yes, they can leave a mess under the nest but people should consider these points.

l These birds travel thousands of miles to nest in our country and no doubt have done so for hundreds of years.

l Nest building is part of the breeding cycle, and as we know the construction of their nest involves a lot of exhaustive work.

l If their nest building is interrupted, nature tells them to start again whether they are exhausted or not. This will of course mean that by the end of their season here in the UK, they could still have young in the nest when the weather gets colder. This could affect their chances of survival and their departure to their over wintering grounds.

“Finally, the birds are given protection under the Wildlife and Countryside Act which states something on these lines that, ‘it’s an offence to intentionally interfere with a nest once it is built or is under construction.’

“We should leave these lovely birds to do what comes naturally, so that our children’s children can enjoy what a lot of us take for granted. For more information regarding the above please contact the RSPB on (01767) 693690 or e-mail: wildlife@rspb.org.uk