The main approach is to attempt to count the number of singing birds which will give a figure for the number of birds in an area. Walking through a territory often causes the resident bird to take flight and start to sing, and adjacent birds will often sing 'against' each other. Regular walking of the survey area should provide a solid figure, and the more counts you make within a short period the better your estimate of numbers will be. Ideally, survey between early April and mid May.
Last updated 12 February 2002.