South Gower Cliffs - Gower - page 105

A recent and exciting addition to the breeding birds on the coastal cliff slopes is the Dartford warbler
Sylvia undata . The Dartford warbler is a relatively sedentary bird and is unusual among British warblers
in not migrating for the winter. It is usually associated with dry heathland with mature heather and plenty
of gorse, a habitat that is plentiful in the peninsula. In colder areas than Gower it runs the risk of starving
to death in a severe frost when it cannot locate the insects on which it relies for food. The warbler is
particularly associated with young gorse bushes as these have an abundant invertebrate fauna. In contrast
maturebushes,whicharehollowbelowthecanopyandthereforecontainfewerinvertebrates,arenotutil-
ised by the birds. Gorse that is cut or burnt over a fifteen-year cycle, though, has been shown to provide
an ideal habitat for Dartford warblers, and this is another factor that makes the Gower cliffs attractive to
this species.
Dartford warblers were once found throughout southern England, but following a severe reduction in
the bird's habitat it was rarely recorded outside Hampshire and Dorset until the mid-1990s. There is an
interesting record, however, of an individual bird in Gower, at Langland in December 1969, and another
individualwasrecordedinSingletonPark,Swansea,inApril1980.TwoDartfordwarblerswerealsoseen
during a survey of Llangennith Moors in 1991, but it was not until ten years later, in 2001, that the spe-
cies was discovered breeding in the peninsula near Port-Eynon Point. More recently in 2003 there were
sightings of birds at Rhossili. There has therefore been a clear westward expansion of its range in Wales.
Growing numbers of native birds like the Dartford warbler, which used to stay close to the south coast,
have now ventured northwards - and this is almost certainly due to global warming.