Troglodytes troglodytes – DRYW – Breeding resident
|No of tetrads occupied||448 (of 478)|
|Percentage of tetrads||93.7%|
A common resident to Mathew (1894) and Lockley et al. (1949). Today Wrens nest everywhere in Pembrokeshire apart from the mountain tops and the smallest offshore islets such as Grassholm and the Smalls (see map). At an estimated 100 pairs per tetrad the population probably totalled about 40,000 pairs during the 1984-1988 Breeding Birds Survey.
Wrens suffer high mortality during severe winters, that of 1963 being particularly devastating. Numbers recover quickly in subsequent breeding seasons provided no further cold winters intervene. Wrens are predominantly woodland birds in Pembrokeshire during times of low population, suggesting that this is their preferred habitat and that other places are occupied as increasing numbers enforce expansion; for instance, Skokholm was colonised for the first time in 1987 when the mainland population was high.