14 January 2000

PONDERING THE REASONS FOR THEIR DECLINE

What is the real reason for the decline in farm birds? Donald MacPhail talked to farmers,

academics and naturalists and Lincs farmer and ornithologist Nicholas Watts adds his opinion

EACH morning Aubrey Char-man walks the fields of Great House Farm, Southwater, West Sussex. Its land he knows well. His great great grandfather arrived in 1823 and the family are still tenant farmers there.

As he walks part of the 81 ha (200 acres) of heavy clay grassland, 89-year-old Mr Charman reflects on the changes he has seen in the landscape as the 20th century has passed and drawn to an end. His son Barry runs 100 Friesians with 70 followers, but Mr Charmans father grew 100 acres of wheat, beans, oats and mangolds, and kept 30 cows, sending milk to London each day by train.

He remembers as a boy pulling up docks – tuppence per 100 – as the reaper binder passed round, and watching as startled corncrakes and quail ran from its path. And summer mornings, the air heavy with the sounds of skylarks, song thrushes and blackbirds. And the sparrows; huge flocks, wheeling and chattering, arriving as harvest approached. "Ive seen 1000 sparrows fly off a hedge and clear every grain of wheat which was almost ready to cut. They would clear an acre of fathers corn in two days."

So damaging were these mixed flocks of house and tree sparrows that workmen armed with sparrownets – huge folding nets mounted on 10ft poles – were hired to catch the birds as they roosted in corn hicks. Driven into the nets, which were then folded over, the trapped birds were quickly despatched.

But these giant flocks are now distant memories; as much an image from another age as horsedrawn binders, sparrow pie, daily milk trains to London.

Figures from monitoring group the British Trust for Ornithology show that in the UK between 1972-96 tree sparrow numbers fell by 280,000 pairs – a drop of 87%; house sparrows by 4,800,000 pairs (down 64%); skylarks by 2,300,000 pairs (down 75%); song thrushes by 950,000 pairs (down 50%); blackbirds by 2,050,000 pairs (down 33%).

Intensive farming is widely blamed for these declines, but attention has also been drawn to huge increases in numbers of voracious songbird predators – most visibly magpies and sparrowhawks.

BTO figures show a magpie population of 650,000 pairs, a 100% increase since 1972 and the highest level for 200 years. The sparrowhawk population in 1986 was estimated at 34,000, up almost 300% from the 1960s. Sparrowhawk numbers have returned to 1940s levels following decimation by organochlorine pesticides – although recent surveys indicate local declines. Magpie increases are attributed to a decline in gamekeeping, maturing suburban habitats and possibly easier scavenging from increased roadkills.

&#42 No doubt about blame

Mr Charman has no doubt where the blame for farmland bird decline lies: "Hawks will eat any small bird they can find, even killing birds at garden tables. But the worst enemy is the magpie. They follow hedges, eating all the young birds and eggs they find. Now there are no gamekeepers to shoot them, and there are thousands of magpies. Sparrowhawks and magpies are the culprits."

But BTO spokesman Nick Carter says a recent close study of long-running bird population data sets yielded nothing to back these claims. "There was no evidence that either magpies or sparrowhawks were having any effect on songbird populations."

Instead Mr Carter says patterns of population crashes support claims that intensive agriculture is responsible. He highlights the switch from spring to autumn-sown cereals – meaning less winter stubble, and probably unsuitable for skylark and lapwing nesting; the use of more potent pesticides, and more intensive grassland management.

"Its simplistic to say the decline is all down to intensive agriculture," responds Game Conservancy Trust spokeswoman Kate Davey. "We cant blame farmers all the time. That simply isnt the case."

While acknowledging the role of more selective pesticide use and woodland and hedgerow management in its game species management, Ms Davey adds: "If youre doing four or five things its quite difficult to isolate which is most effective. But we would say predation control is a major part of our success."

Success is found at the trusts farm at Loddington, Leics, where management techniques have seen songbird populations rise on average 40% and song thrush numbers increase from 14 to 48 pairs in six years.

Stressing that the trust absolutely condemns persecution of raptors, which are protected by law, Ms Davey adds: "In areas where crows are still controlled, youll generally find much higher songbird populations."

This chimes with Mr Charmans call for Larsson traps which use a live decoy to lure magpies. He says he knows of a farmer who caught 130 by this method in a year.

To Prof Tim Birkhead of the dept of plant and animal sciences at Sheffield University, who has studied magpies for more than 20 years, this is the continuation of 150 years of persecution. "Magpies are equated with vermin and old habits die hard. On the basis of work I did with the BTO which found no link, I believe culling is unlikely to be of any benefit."

&#42 Culling nonsense

Dr Alan Woods, environment advisor to the Country Landowners Association adds: "Trapping corvids (magpies, crows, rooks etc) is fine to tackle specific problems. But suggesting that removing sparrowhawks and corvids would lead to a sudden renaissance in farmland bird populations is nonsense."

Culling does not seem "nonsense" to Peter Bryant, general manager of the Royal Pigeon Racing Association who describes sparrowhawks as "a curse all over the UK". With 70,000 pigeon fanciers in the UK with some 15-20 million birds, Mr Bryant estimates 14% of trained birds are lost on flights each year – a great many to raptors.

In impassioned debate in farmers weekly letters pages, readers accuse the Royal Society for the Protection of Birds of hypocrisy for celebrating raptor increases while lamenting songbird losses. One reader suggested the RSPB should be renamed the Royal Society for the Persecution of Birds.

"This reaction is perfectly understandable if you see a magpie working a hedgerow, or a sparrowhawk swoop on a bird table," says Julian Hughes, RSPB species and habitat control officer. "We all feel the same emotion.

"But if you look at the studies, the science, and think about it logically, predation by sparrowhawks and magpies probably isnt having an effect."

Pointing out that "sparrowhawk fodder" such as bluetits and chaffinches have increased in recent years, he adds: "If sparrowhawks didnt eat bluetits wed be knee-deep in them."

Despite RSPB findings, Mr Hughes concedes its feasible predation may play a role in songbird decline. "As populations decline and become fragmented predation may become more of a factor. But he adds: "However, its the change in habitat which is providing long-term decline and resulting in conditions for increased predation.

"Were not blaming farmers individually; theyve followed the trends and demands of governments over the past 40-50 years. But there are things in pesticide use or hedgerow provision which could be improved, and we believe farmers should be assisted in this."

Another possible factor is climate change, says Mr Hughes. "If changes are happening more rapidly than previously, its going to be more difficult for birds and other wildlife to adapt. But until we get another 10 to 15 years down the line no ones really going to have a clue what the relative importance of this is."

&#42 More susceptible

The BTOs Nick Carter is unconvinced: "Most severe changes are taking place on farmland. This tends to indicate that the decline is not an effect of climate changes which you would expect to affect populations in most habitats. Unless, that is, theres something in farmland which makes birds more susceptible to climate change or disease. This is unlikely."

"Its difficult to say anything for certain," admits Mr Hughes. "Factors are all interwoven; weather, deterioration of habitat and predation all work off each other. Its difficult pick one and say its the absolute cause."

Meanwhile Mr Charman continues to walk the fields. Surveying his familiar Sussex landscape, thinking back across the century to long-gone ghostly flocks, he reflects on how eerily silent it has become. "There are just fewer and fewer birds each year."

Winners and losers in the fight for survival: Below: skylark numbers dropped 75% between 1972 and 1996. Bottom Left: Tits are easy

meat for sparrowhawks. Centre left: Magpies

eat eggs and young birds. Left: House

sparrows: once common,

now increasingly rare.

Guilty party? Many farmers blame sparrowhawks for the drop in bird numbers.