DARTFORD WARBLERS SYLVIA-UNDATA, THEIR HABITAT AND CONSERVATION IN THE NEW FOREST, HAMPSHIRE, ENGLAND IN 1988

The breeding range of the Dartford warbler Sylvia undata extends over much of maritime western Europe as far north as southern England, where it is more or less confined to lowland heaths. It is vulnerable to extended winter snowlie and periodically its numbers and range have contracted to the distribution centre in Hampshire and Dorset in south-central England. In a census of the species in the New Forest, Hampshire, in 1988, 454 occupied territories were found, 123% more than in a 1984 survey and the largest number recorded since surveys began in 1960. The increase was attributable mainly to four mild winters. In 1988 the New Forest may have held nearly 75% of the national population of Dartford warblers compared with 48% in 1984. In 1984 most pairs were in the south and east but in 1988 there was a more even distribution, reflecting adjustments in the management of the heaths by burning. In 1988, 402 pairs (89%) were in mature dry heath, humid heath, or thickets of gorse Ulex europaeus These vegetation types covered 1830.6 ha, comprising 22% of the ericoid heathland in the New Forest, and had remained unburnt for at least 15 years. We consider that it is probably not possible to increase the amount of Dartford warbler habitat by changing the burning rotation. However, there may be opportunities to restore heathland on some areas planted with conifers. In this event, attempts should be made to create Dartford warbler habitat on the restored heathland.