Common scoter national breeding surveys in Britain

Royal Society for the Protection of Birds

Description

These surveys were carried out to establish the status and breeding distribution of common scoter in Britain during 1995 and 2007. The 1995 survey was the first national survey, however other regional surveys and estimates suggested that the British population was in decline. The 2007 survey was designed to explore whether the species had continued to decline.

The 1995 survey was carried out by the Wildfowl and Wetland Trust (WWT) and the Irish Wildbird Conservancy (IWC) with financial support from the Royal Society for the Protection of Birds (RSPB), the Joint Nature Conservation Committee (JNCC), Scottish Natural Heritage (SNH) and the Wildfowl and Wetland Trust (WWT). The 2007 survey was carried out by the Wildfowl and Wetland Trust (WWT) and the Royal Society for the Protection of Birds (RSPB). These surveys were both carried out under the Statutory Conservation Agencies and RSPB Breeding Birds Scheme (SCARABBS) partnership, with support from the SCARABBS partner organisations.

Geographic Description

The national common scoter surveys covered the following areas: Shetland, Flow Country, West and South Scotland and Islay. Record precision is the area of the loch. Grid references indicate a location on or near the lochs where the species was recorded, and may not indicate the exact location where the species was seen.

Data quality

These data have been gathered by trained field-workers and the data are of a high quality. These data have been mapped and checked for sensitivities and typographical/geographical errors.

Methods

Three visits were made to all known breeding sites and a sample of potential breeding sites. The surveys were carried out between March and June and were timed to coincide with the common scoter's arrival in Britain, prior to breeding, when birds spend most of the day in open water. During the 1995 survey, three visits were made to all known and a sample of potential breeding sites. The 2007 survey followed the same approach and each site was visited three times (once within each two-week period of the six-weeks of the survey) and was based on a three-stratum design. Stratum one included lochs for which there have been records of breeding or potentially breeding scoter during the 1995 survey or since. Stratum two consisted of lochs, at which breeding had been recorded historically, but not during the 1995 survey nor since. Stratum three were lochs that were randomly selected from all lochs within 20 km of a stratum one site (as long as the lochs met certain criteria). In addition, there are also some records, which have been allocated to stratum four (sites for which information was available from RSPB Forsinard reserve, and would effectively fall into either stratum 1 or 2). Some records do not have a stratum and this is because they were sites that were visited supplementary to the survey design either by surveyors from the Wildfowl and Wetlands Trust or by other surveyors.

Citation

These data were collated under the Statutory Conservation Agencies and RSPB Breeding Birds Scheme (SCARABBS) partnership. Please acknowledge the SCARABBS programme and the Wildfowl and Wetland Trust (WWT), the Royal Society for the Protection of Birds (RSPB), Scottish Natural Heritage (SNH) and the Joint Nature Conservation Committee (JNCC) in any use of the data.

Rights

CC-BY

Digitised records