By Heather Driscoll-Woodford
Conservationists' fears that the South East's Dartford Warblers may not have survived the freezing winter have been allayed by new sightings of the birds.
Our smaller birds have struggled with the extreme conditions in the last couple of years, with the Dartford Warbler being no exception.
Cold weather in 2009 caused a 90% reduction in warbler numbers across the Thames Basin and Wealden Heaths.
New reports are a positive sign that Surrey's warblers are still present.
The Dartford Warbler is rare in the UK and lives almost exclusively in the South. It was first found in England in 1787, and prefers milder winter weather than we have experienced recently.
It also depends on our local heathland habitat for survival, feeding on the insects and spiders which live on plants such as gorse.
In the last 30 years, warbler numbers in the Thames Basin and Wealden Heaths Special Protection Areas (SPAs) have grown from around 200 to 2000.
DARTFORD WARBLER SIGHTINGS
Chobham Common SSSI
Bourley & Long Valley SSSI
Castle Bottom to Yateley
Hawley Common SSSI
However, freezing weather and snow in the early parts of 2009 and 2010 caused concern that the small birds could die out in Surrey and the rest of the South.
Carole Mortimer, Natural England conservation adviser for Chobham Common, says: "This species is on the edge of its natural range and is therefore at the mercy of the weather, so it is good to see the signs that the worst has not happened."
Now, conservationists are calling for the public to take care not to disturb the birds during the coming nesting season.
Samantha Dawes, RSPB Conservation Manager, says: "We are delighted to hear that some Dartford Warblers have hung on in heathland sites in Surrey. However, the surviving Thames Basin Heaths birds are still in perilously low numbers."
"Dartford Warblers are particularly sensitive to disturbance from people and dogs during the nesting season. The same goes for Nightjars and Woodlarks which are also present on these rare lowland heathland sites."
"Any such disturbance will set back their recovery even more."
The Dartford Warbler normally raises two broods of young each summer so could recover its numbers quickly, if the weather stays mild.
The Thames Basin and Wealden Heaths Special Protection Areas SPAs together extend from Bramshill, Crowthorne and Chobham in the north along the Hants/Surrey Border to the Devil's Punch Bowl and Woolmer Forest in the south, and include well known beauty spots such as Yateley, Horsell, Whitmoor, Frensham and Thursley Commons and large areas of military training ground including Ash and Longmoor Ranges.
Special Protection Areas and their Sites of Special Scientific Interest are internationally significant and safeguarded under European law.