On May 5th, right on schedule, swifts arrived screeching over my house.

Poet Ted Hughes famously wrote that when swifts returned from Africa he knew 'the world was still working'.

Sadly however it is no longer working in my immediate area. For three months ago, a large building near me, home to a colony of swifts for many decades, was enshrouded in scaffolding for repairs to roof and gutters, thus denying the swifts access (pictured)

When they arrived they flew around for several days before giving up and I doubt if they will find alternative accommodation this summer.

So, no longer can I enjoy those sickle-winged birds flying above as they have done in their dozens for so many years.

Increasingly, lack of nesting sites is a major problem for swifts as houses and buildings stop up eaves and roof spaces and in fact the bird's population has declined by almost half in twenty five years.

Acutely aware of the situation, some enterprising and thoughtful house builders and local authorities notably in Exeter, Cumbria and Bristol are taking action by installing nest boxes especially in new buildings .

The same lack of nesting availability also applies to the house sparrow and is a major reason for their dramatic decline.

I know of a few small but viable house sparrow colonies where older properties have not yet sealed roof spaces and which also retain privet hedges in front gardens, another requirement for the birds.

So, swift action needs to be taken countrywide to redress the problem and prevent further population declines for both iconic species.