A survey of the United Kingdom's regular breeding birds shows some species in deep trouble, others making a strong comeback and an increase in the number of species that breed here.

The survey, The State of the UK's Birds - 1999, produced by the Royal Society for the Protection of Birds (RSPB) and the British Trust for Ornithology (BTO), reviews what has happened from 1970 until last year.

It says some familiar countryside birds, including song thrushes and grey partridges, have fallen to their lowest numbers on record. Skylarks have suffered a 52% decline, corn buntings 85% and tree sparrows 87%.

Even starlings and house sparrows, which in some regions use farmland for feeding, are now in serious trouble, though the report admits that little is known about their urban populations.

Striking successes

The director of the BTO, Dr Jeremy Greenwood, said: "It is not only farmland birds that are suffering. There have been worrying losses among several woodland species, such as marsh tit, willow tit and redpoll."

Populations are falling in 44 species spread widely across the UK. But the report also details what it calls "spectacular" conservation successes.

Birds of prey such as the red kite, osprey and marsh harrier have all more than doubled their populations in the last three decades.

Other species with populations rising significantly include the blackcap, nuthatch and great spotted woodpecker.

Milder winters, possibly caused by climate change, are thought to be helping. The nuthatches and woodpeckers are continuing to expand their range northwards into Scotland.

And by the end of the 20th Century, there were nearly 40 species breeding in the UK which were not doing so 100 years previously.

A third of them were introduced by humans - species like the golden pheasant, the mandarin duck and the ring-necked parakeet.

But the rest, including the collared dove and the goldeneye, have arrived and settled of their own accord.

Rescue plans failing

In the last 30 years, there has been a net increase of four species each decade. The last arrival was the little egret in 1996.

The report says three-quarters of the UK Government's biodiversity action plans for birds, which are trying to reverse the decline of 26 seriously endangered species, are set to miss their targets.

"The bulk of plans for more widely dispersed birds have largely been unsuccessful. This is simply because the plans' recommendations have not yet been implemented on a large enough scale."

Farm reform essential

Grahame Madge of the RSPB told BBC News Online: "The moral of this report is that the real problem lies with agriculture.

"Many farmland birds are now at their lowest ebb ever, and they are unlikely to increase until we see changes in the way the farm landscape is managed.

"That means massive reform of the European Union's common agricultural policy. We have to look for far more sweeping changes than we've seen so far."