Bird counts from the Glastir Monitoring and Evaluation Programme, Wales 2013-2016

The surveys consisted of four (reduced to three from 2015-16 onwards) visits to each square by trained, professional surveyors using standardised protocols. Surveys were equally spaced through mid-March to mid-July. On each visit, the surveyor walked a route that passed within 50m of all parts of the survey square to which access had been secured, beginning at around 06:00 and taking up to five hours. Surveys were not conducted in conditions known to affect the detection of birds, i.e. strong winds and more than light rain. The survey route was started in different places on each visit, so that all areas were visited at least once before 08:00. All birds seen or heard were recorded on high-resolution field maps using standard BTO activity codes. Recording and standardizing route coverage (where surveyors actually walked) was important both between visits and to ensure comparable repeat coverage when squares are revisited.

Data were recorded on standard forms and field maps, which were collated in the British Trust for Ornithology (BTO) Wales office in Bangor and sent to the BTO head office for digital inputting, after being copied physically and electronically in Bangor. Data were then digitized using ArcMap (versions up to v10.5). The process included checking of uncertain counts, species codes and identifications, for which the digitizer checked the data with the surveyor if necessary, before making a judgement on likely record accuracy. Additional checks were intrinsic to subsequent data processing before being loaded into a final database at UKCEH.

To ensure confidentiality of the data with respect to land owners and managers, the locations of 1km squares and survey sites were converted to the centres of the containing 10km Ordnance Survey grid squares.

This dataset is included in the following collections

Glastir Monitoring and Evaluation Programme, Wales, 2013-2016