Coal Tit - 2003-07

The county breeding population was estimated to lie in the range of 500–700 pairs at the end of the 1984-88 survey. This estimate tried to make allowances for the disparity between densities in conifer plantations and those found elsewhere. It assumed a density of 50 pairs per tetrad in conifer plantations and two to three pairs per tetrad elsewhere. Subsequent experience suggested this under estimated the occupation of non-conifer habitats. This resulted in a lower mean density than the UK average used in the 1988-91 National Atlas, which also showed a relative abundance map showing Pembrokeshire as having a lower than national average. Scaling this proportionally suggests the county figure could have been about 1,100 pairs at that time.

The BBS found there was a 16% reduction in population in Wales between 1994 and 2007, which if applied to the revised 1988 figure for Pembrokeshire, suggests there were about 900 pairs during the 2003-07 survey. However clear felling of conifer plantations took place during the years of the 2003-07 survey which must have reduced Coal Tit numbers. This is not reflected in the survey returns, for some plantations were surveyed before the fellers moved in. To what degree the Pembrokeshire breeding population has been reduced has yet to be evaluated, requiring future study.

Graham Rees

Fieldwork 2003-07 (based on 490 tetrads) 

Red = breeding confirmed = 70

Orange = breeding probable = 120

Yellow = breeding possible = 19

Total tetrads in which registered = 209 (42.7%)