EFFORTS made by Surrey planners to protect a rare bird have failed to halt an 88% population decrease since last year, a survey has revealed.
The Dartford warbler, which was responsible for numerous planning applications being frozen in Surrey because of specially allocated conservation areas, was hit hard by February’s cold weather.
The number of Dartford warblers has plummeted from 1001 pairs last year to 117 in 2009.
Ash Ranges was formerly the prime site in the country for Dartford warblers with up to 250 pairs counted there in recent years, equivalent to five to 8% of the entire population.
Numbers have now sunk to 21 pairs in 2009. The rare bird, which feeds mostly on insects it finds on heathland plants, struggles to survive if heavy snow covers its habitat.
Two Special Protection Areas (SPAs), one on the Thames Basin and the other on Wealden Heaths, were created specifically to aid the conservation of the Dartford warbler along with two other threatened heathland birds, the woodlark and the nightjar.
Before February, the last three decades had seen an increase from under 100 pairs in 1982 to around a thousand pairs in 2008 on the two SPAs.
The birds have prevented thousands of homes across the county from being built, jarring with the government’s bid to put another 580,000 houses in the South East over the next 20 years.
John Clark, from 2Js Ecology, said that although Dartford warblers had been doing well on both SPAs in recent years, the devastating effect of this winter has shown how vulnerable these birds are.
He added that this underlined the need for continuing efforts to improve and extend the heathland habitat on which the species depends.
“The important thing is to preserve the habitat for when the bird comes back,” he said.
“The potential is there for the bird to bounce back. Without the habitat, it doesn’t matter how many birds return. To allow development there would be a travesty.”
Carol Humphrey, head of planning services at Guildford Borough Council, said: “A drop in numbers of the Dartford warbler threatens this internationally important bird’s survival, which means it is even more important that our strategy deals with the adverse effects of development on the bird population, robustly.
“The money that we seek from development continues to be used to provide alternative access to green spaces – this can only assist in ensuring the bird population’s recovery.”
Carole Mortimer, Natural England conservation officer, said that they regretted the decline in numbers for this bird.
“It is an important species on Surrey’s heathlands and we will continue to work to ensure there is suitable habitat for them, but this species is on the edge of its natural range and is therefore at the mercy of the weather,” she said.
“Weather-driven population crashes are part of the natural dynamics for the bird. The Dartford warbler is particularly sensitive to disturbance during the nesting season from domestic pets and public recreation and any such disturbance limits the ability of the birds to recover.
“So, in a year like this, habitat enhancement and the reduction of disturbance is even more important and we continue to work with local authorities to try to ensure that this disturbance is minimised.”