Saturday, August 10, 2013 at 8:21AM Sylvia communis communis
After the willow warbler, the most numerous warbler on passage on the islands. Common summer resident, breeding regularly on Caldey, Skomer, and occasionally on Skokholm. Has bred on Ramsey.
R.M.Lockley, G.C.S.Ingram, H.M.Salmon, 1949, The Birds of Pembrokeshire, The West Wales Field Society
Friday, June 29, 2012 at 6:09PM Whitethroats are perky, largely brown warblers are widespread in the county during the summer. They are particularly evident during their frequently performed song flights, when their disjointed, scratchy song draws attention to their presence. They inhabit heathlands, scrub, hedgerows, woodland edge and very young tree plantations. Nests are placed in low bushes, nettles, brambles and tall grass.
The map shows a similar distribution between the two local surveys at the tetrad level. Some minor changes were noted at a more local level, where young plantations had grown to the point where they became untenable for Whitethroats. Assessing population levels at any given time has been complicated by periodic collapses in numbers. In 1969 the British population was reduced by about 77%. This was associated with drought conditions in the African area where Whitethroats winter. Subsequent recovery has been interrupted by further population crashes of varying magnitude. By 1974 the breeding population had stabilized at approaching half the pre 1969 level but the subsequent recovery was interrupted by another crash in 1984. The 1984-88 Pembrokeshire survey took place in a period of recovery and by 1988 it was estimated to have reached an average density of 20 pairs per tetrad, giving a county total of 8,000 pairs. The similar returns for the 2003-07 survey would seem to indicate no change in the county population but in the meantime the BBS calculated a 10% increase between 1994 and 2007 but a decrease of 18% between 2000 and 2005. It seems that the estimate of 8,000 pairs in Pembrokeshire by 2007 is realistic, despite fluctuations during the time between the two local surveys.
Graham Rees
Fieldwork 2003-07 (based on 490 tetrads)
Red = breeding confirmed = 115
Orange = breeding probable = 289
Yellow = breeding possible = 12
Total tetrads in which registered = 416 (84.9%)
Sunday, December 25, 2011 at 10:35AM Breeding summer visitor and passage migrant. Not recorded in November
Whitethroats were classed as common summer residents by Mathew (1894) and Lockley et al. (1949) and this was the situation until 1967. In 1968 only about 30% of the population returned to breed. This depletion was noted throughout Britain and has been attributed to poor survival on the Whitethroats' drought- stricken wintering grounds of the Sahel (Sharrock 1976). Recovery has been gradual and the population at the time of the 1984-1988 Breeding Birds Survey, with an average density of 20 pairs per tetrad, was probably about 8,000 pairs.
They generally arrive in Pembrokeshire between the middle of April and early June, but in some years occur from the 5 April onwards, with one at Fishguard on 23 March 1956. Their passage is dramatic, with thousands passing in a series of waves, particularly noticeable on the islands and headlands. Some diurnal falls are spectacular, such as the estimate of about 500 at Skokholm on 22 May 1959. They have been noted at night at the lanterns of the South Bishop and Smalls lighthouses.
They pass through the islands and coastal areas again between late July and 31 October, but are less numerous than during the spring passage.
A male was a regular visitor to a Haverfordwest bird-table from 20 December 1990 to April 1991.
Fieldwork 1984-88 (based on 478 tetrads)
Red = breeding confirmed = 137
Orange = breeding probable = 248
Yellow = breeding possible = 21
Total tetrads in which registered = 406 (84.9%)
Sunday, November 13, 2011 at 7:05PM 
Red = breeding confirmed
Orange = breeding probable
Yellow = breeding possible
Sunday, September 26, 2010 at 12:41PM Species account from M Mathew, 1894, "The Birds of Pembrokeshire and its islands"
