Dotterel national breeding survey in Britain in 1999 - raw data

Royal Society for the Protection of Birds

Description

These data are from a national survey of breeding dotterel <i>Charadrius morinellus</i> carried out in 1999. This was the second national survey of breeding dotterel in Britain, undertaken to provide a reliable population estimate for dotterel.

This dataset contains the raw data and data for other species such as skylark and meadow pipit, which were also recorded. The other species records, collected using non-standard methods, are in a separate survey within this dataset.

Over half of the potential breeding habitat of Dotterel in Britain was selected for survey using a random sampling technique. Ireland was not included due to the lack of recent breeding records. Two methods were used to estimate the population size, with an agreed best estimate of 630 breeding males (Whitfield, 2002). The number of pairs estimated in Whitfield (2002), were derived from an analysis of these raw data.

The national population estimate was significantly higher in 1987/88 (estimated to be 840 breeding pairs), but numbers were probably greatest in 1989 and declined in the 1990s. The change in numbers may be due to influences away from the breeding grounds or a redistribution of birds away from Scotland to breeding sites elsewhere in the Palaearctic.

This survey revealed that the population had contracted and the majority of the birds (almost 93% of the population) were breeding in three regions in Scotland: the central and east regions and in the north Highlands.

This survey was carried out under the Statutory Conservation Agencies and RSPB Breeding Birds Scheme (SCARABBS) partnership. The survey was funded by Scottish Natural Heritage (SNH) and the Royal Society for the Protection of Birds (RSPB).

Geographic Description

This is a UK wide survey, though the majority of the population is in Scotland. Ireland was not surveyed due to a lack of recent breeding records. The data have been recorded at 100m resolution.

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

The survey was based on sample counts on selected potential breeding sites in dotterel breeding habitat (the montane zone above the former tree line). Areas within the montane zone, unsuitable for breeding were excluded from survey.

Potential survey areas were digitised and the site boundaries are held by the RSPB in GIS format. The Site Numbers and Site Names in this dataset refer those digitised site boundaries, which are available from the RSPB on request.

Over half of potential dotterel breeding habitat was selected for survey. 128 survey sites were selected randomly and an additional 49 sites were selected because they were either protected sites or former breeding sites. Surveyors walked within at least 100m of every point on each site once during the period when most male dotterel attend chicks and are more visible before chicks fledge (typically 20th June - 18th July). The male provides most parental care and are most visible before chicks fledge. Observation of a male before the fledging period is likely to represent a probable breeding attempt and therefore, the male was the unit of breeding population estimates.

Citation

These data were collected under the Statutory Conservation Agencies and RSPB Breeding Birds Scheme (SCARABBS) programme. Please acknowledge the Royal Society for the Protection of Birds (RSPB) and Scottish Natural Heritage (SNH) in any use of the data.

Rights

CC-BY

Digitised records