Cyanistes ceruleus – TITW TOMAS LAS – Breeding resident
Comparison with previous atlas:
| 1984-88 | 2003-07 | |
| Breeding confirmed | 302 | 311 |
| Breeding probable | 54 | 95 |
| Breeding possible | 52 | 23 |
| No of tetrads occupied | 408 (of 478) | 429 (of 490) |
| Percentage of tetrads | 85.4% | 87.6% |
It was estimated that 24,000 pairs were nesting in Pembrokeshire at the end of the 1984-88 survey, based on a mean value of 60 pairs per occupied tetrad. This was a similar level to that of the 1988-91 National Atlas, using the calculated national average and relative abundance distribution.
Little distributional change was apparent by the conclusion of the 2003-07 survey but the BBS indicated there had been an increase of 29% in Wales between 1994 and 2007. Accepting that a similar increase took place in the county, the population at the end of 2007 was probably about 31,000 pairs. Widespread garden feeding resulting in increased winter survival was undoubtedly a contributing factor to increased breeding numbers.
