Sunday, December 31, 2006

The 2006 National Dartford Warbler survey

Until 2003, when six pairs of Dartford Warblers were found in one location (at least three of which reared young), there had been no previous reported evidence of them breeding in Pembrokeshire (Pembs Bird Report 2003). This year’s national Dartford Warbler survey therefore provided an opportunity to find out if they were still maintaining a foothold in the county, or if there were indications of further population expansion.

Between April and June 2006, 55 tetrads (2km x 2km OS squares) were checked for presence of Dartford Warblers and evidence of probable or confirmed breeding. These included a few targeted locations where there had been recent breeding evidence. Most of the remaining locations surveyed were squares randomly selected by the BTO/RSPB.

Despite a cold, wet and rather unpromising early spring, results were encouraging.

Between 14 and 18 Dartford Warbler territories were recorded in suitable habitat. This was based on mapped registrations of singing/calling males, displaying birds/pairs, or adults with food or young.

Three pairs were just over the border in Carmarthenshire, the remainder were in seven separate tetrads in Pembrokeshire.

It is still early days, but the survey shows that the population, although still small and potentially vulnerable to predation and the vagaries of weather, is still expanding its range within the County.

None of the randomly selected squares had much suitable heathland habitat and no Dartford Warblers were found in them. However, at least 38 Stonechat territories (Stonechats were an additional species to record) were found. These were reported in more than 50% of the tetrads visited – providing some additional information for the ongoing Pembrokeshire Breeding Birds survey.

Fieldwork for the survey relied on a team of volunteers. The following observers contributed records:

John Best, Sam Bosanquet, Ian Bullock, Jonathon Copp, Richard Crossen, Richard Ellis, Steve Gerlach, Bob Haycock, Jane Hodges, Greg Morgan, Trevor Price, Graham Rees, Steve Sutcliffe and Matt Sutton.

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