Crested tit wintering survey in the UK, 1992-1995

Quality Control

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

Method steps

1. The woodlands in the Moray firth area, which encompasses the breeding range of the Crested tit population in Scotland, were stratified according to ancient native pinewoods and other woodlands, which were primarily conifer plantations. Forty transects within ancient native pine woodlands were selected systematically and 81 transects were selected in other woodlands using random six figure grid refs which fell within this range.
   
   
   The transects were all 2KM long and in a triangular formation, they were drawn such that the gird reference fell half way along the primary side of the transect triangle.
   
   
   Once a bird or group of birds was found, 3 measurements were taken; the angle between the bird/group and the transect line, the distance from the observer to the group and the number of birds in the group. Birds were most likely to be detected by calls so there was no difference in detection between birds on the far or near edge of the group. Estimates of the bird density were then calculated using the DISTANCE programme. This dataset contains the raw sightings. Further details of how populations were derived are explained further in Summer et al (1999).

The breeding range of the Crested tit, Moray Firth area in Scotland.