Sylvia borin – TELOR YR ARDD – Breeding summer visitor and passage migrant. Not recorded in January, March and December
|No of tetrads occupied||193 (of 478)|
|Percentage of tetrads||40.4%|
Mathew (1894) found the Garden Warbler to be a scarce summer visitor, whereas Lockley et al. (1949) considered it widely distributed but local.
Today they breed commonly, their distribution showing a heavy bias towards the eastern half of the county (see map). An estimated average density of ten pairs per tetrad suggests a total breeding population of about 2,000 pairs. They arrive back on the breeding grounds from early May and become increasingly difficult to find from mid-August.
Up to ten Garden Warblers at a time occur on the islands and in scattered coastal areas from 23 April to 25 June, with occasional earlier birds from 6 April onwards, and again between 17 July and 28 October. They have been noted at the lantern of the Smalls lighthouse at night in May, August and September. Late birds were at Skokholm on 2 November 1968 and at Picton on 27 November 1977. A Garden Warbler seen at Pembroke on 28 February 1976 may well have overwintered, and another was trapped for ringing at Pwllcrochan in February 1992.