I AGREE with J V Bradford (Letters, March 11) that the maligned sparrow hawk and other raptors have always been a natural predator of small birds, without decimating their numbers.

But because of the dramatic decline of their quarry in the open countryside, sparrow hawks have now encroached into cities and other urban areas for easier pickings.

Over the past 50 years or so, nearly all birds (barring a few, including the magpie) have plummeted to worryingly low populations.

Many reasons are given why birds are declining rapidly. Their habitat for nesting and food sources are no longer in plentiful supply, having been lost to modern agricultural practices and the unrelenting building programmes that result in more scrubland and meadows being lost.

Tens of thousands of houses have been built, sharply increasing the domestic cat populations (RSPB estimate ten million in the UK) that now cash in on the ever depleting bird numbers. The grey squirrel with numbers out of control are also a threat.

Poisons readily available from shops and DIY stores are often indiscriminately put out for vermin, and are then taken by birds. Until these issues are addressed, bird numbers will continue to fall.

D A Heald,

Huntington Road, York.

Updated: 09:38 Wednesday, March 15, 2006