Sunday, December 25, 2011 at 10:04AM Vagrant
One bird trapped and ringed at Skokholm on 13-14 May 1967 (C. Britton) was the first for Wales, and was followed by another on 11 May 1970 (B. Chambers). None have been recorded since daily trapping ceased at Skokholm in 1976, nor has their loud and distinctive song been heard from any of the mainland reedbeds.
Sunday, December 25, 2011 at 10:00AM Breeding summer visitor and passage migrant. Not recorded from December to March
Reed Warblers were not recorded by Mathew (1894), while Lockley et al (1949) noted just four records, the first being at the Smalls lighthouse on 17 October 1908.
They were first proved to be breeding at Nevern in 1975, although they had been present in suitable reedbed habitat at Pentood and Slebech from 1974. However, Lloyd records in his diary that H.R. Chubb claimed to have seen a pair and their nest at Goodwick Moor in 1934 or 1935, and Lloyd himself strongly suspected that they had bred at Tenby Marsh in 1931. They have continued to colonise Pembrokeshire since 1975, and may now have occupied most of the available suitable habitat. The total breeding population is currently about 60 pairs (see map).
Reed Warblers are occasionally detected on both spring and autumn passage, from 26 April to 17 June and from 22 August to 25 October. Singles were recorded at Skomer on 7 July 1986, at Strumble Head on 1 November 1987 and at the Smalls on 2 November 1982.
Fieldwork 1984-88 (based on 478 tetrads)
Red = breeding confirmed = 8
Orange = breeding probable = 10
Yellow = breeding possible = 3
Total tetrads in which registered = 21 (4.4%)
Sunday, December 25, 2011 at 9:57AM Breeding summer visitor and passage migrant. Not recorded from November to February
Mathew (1894) considered the Sedge Warbler to be the second most numerous, after the Chiffchaff, of the warblers to visit Pembrokeshire. Lockley et al. (1949) stated that it was a "numerous summer resident in almost every reedy, sedgy cover". Lloyd's detailed diaries for 1925-1935 recorded Sedge Warblers in localities where they are now absent, the habitat having become unsuitable. Lockley (1957) stated that "they can be found singing in every overgrown water ditch". Sedge Warblers are less numerous in Pembrokeshire today, the Breeding Birds Survey of 1984-1988 finding them to be locally distributed. Most were found in reedbeds and other marshy areas but some were breeding in completely dry scrubby places, including pairs at Haverfordwest Golf Course, around Mathry and along parts of the coastal path. Numbers vary from year to year, depending on how they survive the rigours of migration and the conditions they encounter at their wintering grounds south of the Sahara. They were noticeably less numerous during the first two years of the survey than in the latter three. By the end of this period there were estimated to be about 650 pairs breeding in Pembrokeshire. This is based upon individual assessments at some of the larger marshes plus an estimated average density of four pairs per tetrad elsewhere.
Sedge Warblers generally appear in Pembrokeshire in the second half of April, with occasional birds in the vanguard from 6 April. One was at Tenby Marsh on 25 March 1964. They continue to pass until about 9 June, and occur in most coastal areas, with occasional notable falls such as the 250 birds seen at Skokholm in May 1953.
Return passage is spread between July and 17 October, though one was recorded at Skomer on 29 October 1963. Usually ones and twos are seen in coastal areas, with occasional falls of 20 or so, although up to 100 were recorded at Skokholm in August during the 1940s.
Fieldwork 1984-88 (based on 478 tetrads)
Red = breeding confirmed = 30
Orange = breeding probable = 91
Yellow = breeding possible = 13
Total tetrads in which registered = 134 (28%)
Sunday, December 25, 2011 at 9:56AM Rare visitor
Single birds have been recorded at Skokholm on 6 September 1949, on 20 and 21 September 1961, on 24 August 1970, on 19 September 1971 and on 13 October 1980. Another single was at Skomer on 20 September 1985, and two were there from 7 to 9 September 1990. They are difficult to see in the dense cover which they favour. Frequent mist-netting of reedbeds might reveal that they occur more often.
Sunday, December 25, 2011 at 9:54AM Vagrant
The first to be identified was trapped at Skokholm on 31 October 1968 (C.Britton), and another one singing at Dowrog on 18 June 1983 (C.Lambourne et al) was recorded on tape.
Sunday, December 25, 2011 at 9:52AM Breeding summer visitor and passage migrant. Not recorded from December to March
The Grasshopper Warbler was a summer visitor with a local breeding distribution to both Mathew (1894) and Lockley et al. (1949), the latter noting that it was a scarce passage migrant on the islands in spring but had only once been recorded in autumn.
Now they are regular in spring between 7 April and early June, sometimes occurring in considerable numbers on the headlands. They sing from cover but also from exposed perches, and up to 40 have been recorded in a day at Skokholm.
Grasshopper Warblers are still locally distributed (see map), occupying patches of rank growth such as fen, common and scrubby grassland, a commodity that has diminished during the years with the development of intensive farming. They also nest in young conifer plantations including those at Wiston Wood and Pantmaenog Forest. The number occupying suitable habitat varies according to how they fare on migration and in their sub-Saharan winter quarters. On the evidence found during the Breeding Birds Survey of 1984-1988 an average density of four pairs per tetrad, based on singing birds, suggests a total population in Pembrokeshire of 400 pairs. However, this is almost certainly an underestimate.
Grasshopper Warblers are less numerous in autumn than they are in spring, with small numbers passing through coastal areas between 27 July and 21 October. One was recorded at Skokholm on 7 November 1968.
Fieldwork 1984-88 (based on 478 tetrads)
Red = breeding confirmed = 8
Orange = breeding probable = 70
Yellow = breeding possible = 11
Total tetrads in which registered = 89 (18.6%)
Sunday, December 25, 2011 at 9:48AM Breeding resident
The first Cetti's Warbler found in Pembrokeshire stayed at Bosherston Pools from 24 January to 28 March 1979 (D. Henshilwood and J.W. Donovan). The second sang from a reedbed at Poppit on 27 May 1981. These were forerunners of the colonisation which has continued since April 1983. Breeding has been confirmed, and at least five pairs are resident at two sites in the south of the county. They have occupied up to six sites in the breeding season, all south of the Cleddau Estuary (see map) until the Pentood Marshes were colonised in 1990, where there are now at least eight to ten pairs.
They have been recorded at Skokholm, Skomer and Strumble Head outside the breeding period, and such wanderers give hope that they will eventually find other breeding localities; for instance, Mullock, Newgale and Goodwick reedbeds appear to be suitable habitat.
Fieldwork 1984-88 (based on 478 tetrads)
Red = breeding confirmed = 1
Orange = breeding probable = 6
Total tetrads in which registered = 7 (1.5%)
Saturday, December 24, 2011 at 4:16PM Breeding resident
Both Mathew (1894) and Lockley et al. (1949) regarded the Mistle Thrush as a common resident. The Breeding Birds Survey of 1984-1988 found Mistle Thrushes to be more numerous south of the Cleddau Estuary and in north-east Pembrokeshire than elsewhere, where they were sparse. At an estimated ten pairs per tetrad in the main areas and two pairs per tetrad elsewhere, the population would probably be about 1,400 pairs.
They flock from July onwards, in groups varying from five to twenty birds, but over 100 were at Skomer on 3 October 1983 and an estimated 500 appeared on Ramsey on 12 October 1972. Flocks disappear before the winter and Mathew considered that they migrated south. He was probably right but we have found no direct evidence to confirm this.
The Mistle Thrush is generally sparsely distributed during the winter, some territories becoming deserted, while in others residents firmly defend well-berried trees.
Fieldwork 1984-88 (based on 478 tetrads)
Red = breeding confirmed = 89
Orange = breeding probable = 68
Yellow = breeding possible = 57
Total tetrads in which registered = 214 (44.8%)
Saturday, December 24, 2011 at 4:15PM Winter visitor and passage migrant. Not recorded in July and August
Mathew (1894) and Lockley et al. (1949) agreed that the Redwing was a common winter visitor and that cold weather brought great numbers to Pembrokeshire.
Redwings normally arrive in Pembrokeshire from early October, the earliest record being of one at Skokholm on 11 September 1976. Thousands pour through until early December, flocks often stopping off to feed in the fields and on hedgerow berries. Some falls involve large groups, such as about 1,500 at Skokholm on 28 October 1964. Far greater numbers appear to pass at night judging by the frequency of calls overhead, and they have featured strongly at lighthouse attractions at the Smalls, South Bishop and Strumble Head. They have been noted departing out to sea towards Ireland in the early mornings, and one ringed at Skokholm in October 1964 and recovered in France in December the same year illustrates through passage to the south. Icelandic Redwings T. i. coburni, which are longer winged and darker than the Eurasian race T. i. iliacus (Svennson 1992), have been identified in the hand at Skokholm.
The number wintering varies with the weather and the berry crop. Severe weather to the east brings large influxes, many thousands of birds pouring into the coastal region. These immigrants may quickly retreat following a thaw only to return if the weather turns cold again. When cold weather actually grips Pembrokeshire many die, Lockley et al. recording thousands perishing in such circumstances. This scale of mortality has not been recorded since, although 245 were found dead at Skomer in the arctic winter of 1962 (Harris 1962) and many died at Stackpole in 1985, some weighing as little as 50 grams, compared with a normal weight of over 70 grams. They largely vacated Pembrokeshire in the winter of 1986 when, uncharacteristically, several weeks of frost occurred.
There is a distinct return passage from late February to early April, when Redwings are again heard passing at night and seen at the lighthouses. Most have departed by mid-April, but stragglers have occurred until 6 May, and singles have been noted at Skokholm on 13 June 1939 and 18 June 1979.
Saturday, December 24, 2011 at 4:12PM Breeding resident, passage migrant and winter visitor
Mathew (1894) noted that the Song Thrush was a common resident which suffered severe mortality in the cold winter of 1880, while Lockley et al. (1949) added that it was not numerous.
Today they breed throughout Pembrokeshire but are absent from the bare tops of the Preseli Mountains and from all of the offshore islands except Caldey, though they did nest on Skomer in 1961 and 1962. Census work on the Dyfed Wildlife Trust reserves of Rosemoor, Pengelli Forest and the Old Mill Grounds suggests an average density of 15 pairs per tetrad, which would mean a total breeding population of 6,000 pairs.
Grey-coloured Song Thrushes, thought to be of continental origin, pass through in October and November. They are occasionally heard calling from the night sky at this time, have occurred at the lantern of the South Bishop lighthouse and there are periodic falls on coastal headlands and offshore islands.
Larger numbers overwinter in Pembrokeshire. These resemble the local breeding birds and ringing has shown their origin to be elsewhere in Britain, ranging from Midlothian to Oxfordshire. These high winter numbers are sustained by the large snail populations to be found in the hedgebanks. The snails are also important to further influxes of Song Thrushes that appear when cold weather approaches from the east. During such periods they can be seen every few yards along the hedgebanks, and the sound of snails being battered on 'anvils' becomes characteristic of the Pembrokeshire lanes. Song Thrushes seem to survive snow cover of short duration quite well, still being able to find snails, but many then become casualties when they use the cleared roads as anvils, becoming too preoccupied to notice the traffic.
Fieldwork 1984-88 (based on 478 tetrads)
Red = breeding confirmed = 144
Orange = breeding probable = 215
Yellow = breeding possible = 33
Total tetrads in which registered = 392 (82%)
Saturday, December 24, 2011 at 4:11PM Winter visitor and passage migrant. Not recorded in July and August
Fieldfares normally arrive in Pembrokeshire from the middle of October to late November, with occasional earlier birds occurring from 14 September onwards. Large numbers pass though, many stopping to feed during the day and staying into December in years when the berry crop is heavy. Most movement is probably nocturnal; Fieldfares are seldom heard calling from the night sky but they have been noted at the lantern of the South Bishop lighthouse. Coastal falls at well-watched localities indicate variable passage the previous night. There is also an occasional marked diurnal passage, as when about 1,000 came in off the sea from the north and north-east at Strumble Head on the morning of 2 November 1986, to join about 2,000 others that had piled up in the fields there. A party of about 750 departed north-westwards towards Ireland at dusk.
Fieldfares are normally well distributed across the wet pastures of Pembrokeshire during the winter, sometimes forming large roosts. For example, about 4,000 roosted in sitka spruce at Pantmaenog Forest in February 1984. Hard weather brings further large numbers in to the county, many of which pass on, but prolonged severe weather can cause considerable mortality.
Most Fieldfares depart in March and early April, when there is also a through passage. Fieldfares have been noted at the lantern of the Smalls lighthouse at this period. Some linger into May or even beyond, the latest records being 31 May and, at Skokholm, a single bird on 10 and 13 June 1980.
Saturday, December 24, 2011 at 4:09PM Vagrant
One at Skomer from 3 to 5 December 1987 (S.J.Sutcliffe et al) was only the seventh occasion on which this Siberian thrush has been recorded in Britain.