Monday, August 12, 2013 at 7:34AM Turdus merula merula
A common resident. Breeds Skomer, Ramsey and Caldey, irregularly on Skokholm. Numbers increase in autumn and winter.
R.M.Lockley, G.C.S.Ingram, H.M.Salmon, 1949, The Birds of Pembrokeshire, The West Wales Field Society
Sunday, May 13, 2012 at 5:05PM No change in distribution is evident when the results of the two breeding bird surveys are compared, Blackbirds being found everywhere in the county bar the hill tops and the smallest offshore islands. The 1988-91 National Atlas indicated high to maximum abundance in Pembrokeshire, suggesting a higher density than the UK average, so the estimated 100 pairs per tetrad used with the 1984-88 survey results was probably realistic at 45,000 pairs. Since then the BBS has calculated a 47% increase in Wales over the period 1994 – 2007. Applying this increase to the 2003-07 survey plot suggests the Pembrokeshire breeding population could have reached about 66,000 pairs by 2007.
Graham Rees
Fieldwork 2003-07 (based on 490 tetrads)
Red = breeding confirmed = 317
Orange = breeding probable = 128
Yellow = breeding possible = 10
Total tetrads in which registered = 455 (92.9%)
Saturday, December 24, 2011 at 4:06PM Breeding resident, passage migrant and winter visitor
Both Mathew (1894) and Lockley et al. (1949) described the Blackbird as a common resident, the former commenting on a rapid increase in numbers following mild winters. Blackbirds still breed commonly throughout Pembrokeshire, including some of the offshore islands (see map). The encroachment of conifer plantations on the slopes of the Preseli Mountains has enabled them to breed at higher altitudes than before, but they are still absent from the open tops. At an average density of 100 pairs per tetrad, the total breeding population is probably about 45,000 pairs.
Some are resident, which can be confirmed by noting distinctly marked birds, such as partial albinos, staying in territory throughout the year. However, they generally become sparse in late August and early September, a time when it would be reasonable to expect high numbers, with juveniles present as well as adults. Although less conspicuous during moult a careful search seems to indicate a genuine reduction in numbers. It is probable that many leave the county, perhaps emigrating, though we have no proof of this. The appearance of a Blackbird at the Smalls on 18 July 1982 is interesting in this context, but extensive ringing of Pembrokeshire nestlings may be the only way to put speculation to the test.
Thousands pass through between late September and early December, passage being strongest in October and early November. They are heard calling at night and large numbers have been noted at the lanterns of the South Bishop and the Smalls lighthouses. Periodic falls occur around the coast and on the offshore islands, numbers sometimes being impressive; for example, 11,000 were seen at Skokholm on 18 October 1964. Ringing recoveries show that some of these migrants originated in England on an arc from Stafford to North Devon, whilst others came from western Europe, from between Belgium and Norway. Recoveries also show that Blackbirds passing through Pembrokeshire carry on southwards as far as Spain. In addition, they have been seen at sea heading for Ireland.
Blackbirds may well be more numerous during the winter than in the summer, particularly during mild years. Some are continental birds, such as one ringed in Holland in October and recovered at Pembroke Dock in late December. Further influxes occur when cold weather grips Europe and eastern Britain. Many pass on but others stay until they can retreat eastwards again after the thaw. If the severe weather reaches Pembrokeshire, and endures for any length of time, many die, though there have been no modern repetitions of events such as those noted by Lockley et al. (1949), when thousands of birds perished and the beaches became lined with the corpses of Blackbirds and other "soft- billed birds".
There is a return passage in late February and throughout March, when they are again heard passing at night and have been detected at the lanterns of the South Bishop and Smalls lighthouses.
Fieldwork 1984-88 (based on 478 tetrads)
Red = breeding confirmed = 299
Orange = breeding probable = 133
Yellow = breeding possible = 19
Total tetrads in which registered = 451 (94.4%)
Donovan J.W. & Rees G.H (1994), Birds of Pembrokeshire
Pembrokeshire Avifauna committee
Although the 1994 avifauna says that 11,000 Blackbirds were on Skokholm on 18th October 1964, the island log says “c,1,000” so the entry is a typographical error. Still a good number for the island and one of the highest counts for anywhere in Wales.
Thursday, November 10, 2011 at 10:25PM 
Red = breeding confirmed
Orange = breeding probable
Yellow = breeding possible
Friday, September 16, 2011 at 11:38AM GHR
The BTO winter atlas showed that Blackbirds were present in all 10km squares during the winters of 1981-82, 1982-82 and 1983-84.
The darker the colour, the higher the relative total count for each 10km square. The darkest blue represents over 115 birds recorded per day.
Ring recoveries confirm that the large winter presence includes Continental birds.
Sunday, September 26, 2010 at 12:22PM Species account from M Mathew, 1894, "The Birds of Pembrokeshire and its islands"
