The ideal survey route within each 1 km square comprises two parallel transects, each 1 km in length about 500 m apart and about 250 m from the edge of the square. For practical reasons there is often deviation from the ideal route. Each 1 km transect is divided into five 200 m sections, at which level all information is collected.
Once the transect routes are planned, two visits to each survey square per year are undertaken. Bird counts are carried out in the early morning. This is done twice in each survey site (1km square), between 1st April and 30th June:
- The first visit is between 1st April and 15th May - to capture details on residents and early migrants.
- The second visit is between 16th May and 30th June for late migrants.
Habitat data are also recorded during the first visit, using codes from an established hierarchical system common to a range of bird surveys in the UK. recorded.
It is very important that two visits are undertaken each year. Each visit takes about two hours or less. Click here to view the map of 400 squares that are scheduled for survey.