Friday, August 23, 2013 at 7:54AM Delichon urbica urbica
Summer resident, less common than swallow. Nests on coastal cliffs in several places, eg near Newport, Moylgrove, Penrhyn Castle, Bosherston and at Caldey. Considerably less numerous on passage than Swallow.
R.M.Lockley, G.C.S.Ingram, H.M.Salmon, 1949, The Birds of Pembrokeshire, The West Wales Field Society
Thursday, May 10, 2012 at 9:06PM Most House Martins arrive in Pembrokeshire between early and mid April, although there have been sightings as early as February.
House martins are highly dependent on buildings for nest sites with up to 99% of the breeding population building mud nests, or utilising artificial nest boxes positioned high-up on walls beneath over-hanging eaves, which protect the nest and its contents from adverse weather. In Pembrokeshire, a small proportion of House Martins nest in sea caves, or beneath over-hangs on sea cliffs. Colonies can be found, for example nesting in/on sea cliffs to the south of Ceibwr; at Nolton Haven and on the Castlemartin coast.
The 1984-88 tetrad survey confirmed that House Martins are widely distributed as a breeding species across the county. A comparison between this and the 2003-07 tetrad survey suggests a stable or slightly increasing breeding population:
The tetrad map illustrates where localised changes in the distribution of breeding House Martins have occurred in between the two tetrad surveys. House Martins are absent as a breeding species from all the offshore islands, with the exception of Caldey Island, where it was recorded as “probable breeding” during the 2003-07 tetrad survey. They are also absent from the tops of the Preseli Hills and from heavily wooded areas.
Whilst the breeding population of House Martins has generally remained stable or increased overall, localised losses from some tetrads could be due to a number of factors, which may also hold the key to their future as a breeding species in the county. These factors include future availability of suitable nest sites. It is vital that building renovations, as well as new buildings take account of their nesting requirements if they are to continue to grace our skies. The availability of mud for nest-building is also vital as this resource can be easily lost e.g. as a result of tidying up muddy seepages, hollows and puddles. A single source of mud may supply the entire House Martin population on farms or in small settlements. Other key factors include abundance and distribution of aerial insects.
Following the 1984-88 tetrad survey, the total breeding population of House Martins in the county was estimated to be around 4,000 pairs (an average density of 20 pairs per tetrad was assumed).On this basis, an increase of 16% of tetrads where breeding was confirmed during the 2003-07 tetrad survey suggests a total breeding population of about 4,700 pairs.
Jane Hodges
Fieldwork 2003-07 (based on 490 tetrads)
Red = breeding confirmed = 235
Orange = breeding probable = 17
Yellow = breeding possible = not included
Total tetrads in which registered = 252 (51.4%)
Friday, December 23, 2011 at 9:49AM Breeding summer visitor and passage migrant. Not recorded in January and December
A common summer visitor to both Mathew (1894) and Lockley et al. (1949), today House Martins are widespread breeding birds (see map). Most nest on buildings, but there are also thriving cliff colonies at many places around the coast, as at Ceibwr and Nolton Haven, and a colony of three pairs was at Skomer in 1969. At an estimated 20 pairs per tetrad the breeding population is probably about 4,000 pairs.
The first House Martins usually arrive here in early to mid-April. However, birds occur from 20 March in some years, and really early birds were at Pointz Castle on 17 February 1958 and at Moylgrove on 23 February 1984, and one was found freshly dead at Dale on 10 February 1982. This latter record followed a period of southerly winds bearing Saharan sand, which might have borne the bird, displacing it in the same way as moths are taken way beyond their normal range. Northward passage continues on a broad front across the county but most densely at the coast, throughout April and May and into early June. They often pause over freshwater sites, particularly during rain or fog, when congregations of up to 200 occur, as at Pembroke Mill Pond on 17 April 1983.
Southwards movement occurs from late July and continues until October, with stragglers until 19 November in some years. The volume is probably larger than in spring with fewer concentrations, though 250 have been recorded at Skokholm.
Although principally a diurnal migrant they were recorded at lighthouse attractions at the South Bishop on 29 May 1975 and at the Smalls on 20 May 1984 and 29 and 30 September 1983.
Fieldwork 1984-88 (based on 478 tetrads)
Red = breeding confirmed = 197
Orange = breeding probable = 7
Total tetrads in which registered = 204 (42.7%)
Friday, November 11, 2011 at 3:28PM 
Red = breeding confirmed
Orange = breeding probable
Yellow = breeding possible
Saturday, December 18, 2010 at 8:57AM Species account from M Mathew, 1894, "The Birds of Pembrokeshire and its islands"
