Sturnus vulgaris – DRUDWEN – Breeding resident, winter visitor and passage migrant
|Breeding possible||excluded from total|
|No of tetrads occupied||187 (of 478)|
|Percentage of tetrads||39.1%|
Very few Starlings bred in Pembrokeshire prior to 1880 but they have slowly increased since. Mathew (1894) noted that they were increasing and Lloyd’s diaries detail the patchy distribution they had achieved during 1925-1937. Lockley et al. (1949) agreed that they were rare nesters in some parts of the county while Davies (1948) gave details of some 50 pairs•in just eight localities.
The Breeding Birds Survey of 1984-1988 found Starlings to be well distributed in towns but sparse in many rural areas (see map). Very few bred in trees, but they bred freely in rock crevices in mainland cliffs and on the offshore islands. The majority used buildings, and their patchy distribution may be due to a lack of suitable structures in some areas. A population estimate has been made by taking fairly accurate figures from the islands and some mainland towns (where local observers live), and adding them to estimates for other urban areas and to an estimated average of ten pairs per tetrad for rural areas, giving a total of about 2,000 pairs overall.
They flock from June onwards, with juveniles predominating. Many of these are undoubtedly locally-bred birds, but as numbers grow during July and August it seems likely that others from outside the county make their way to the coastal strip.
Vast numbers pass through Pembrokeshire from October to early December, ringing recoveries showing that they include birds from the Continent as far east as Karelia, in Russia. The majority appear overnight and there are many records from the lanterns of the Smalls and South Bishop lighthouses. There is also considerable diurnal movement, principally towards Ireland, including 10,170 logged flying north-west out to sea at Strumble Head on 6 November 1983.
Roosts and murmurations
The coastal pastures of Pembrokeshire swarm with Starlings during the passage period and these are also the principal feeding . grounds for the large numbers that winter in the county. Many small to medium sized roosts are formed but by late December the majority are concentrated into a few large roosts. Sites have varied but in recent times have included the reedbeds at Bosherston Pools and Canaston, and the conifer plantations on the flanks of the Preseli Mountains and at Dudwell. Birds spread out to feed during the day, some travelling considerable distances. The Preseli roost gathers birds from all over north Pembrokeshire as far as the Teifi, as well as from the south and east. The Dudwell birds fly in from St David’s to Fishguard in the north, from the western coastal plain and from the western Castle Martin peninsula. Starlings feeding on the Castle Martin ranges east of Flimston have been noted flying towards the Bosherston, roost but those on Range West depart northwards and the flightlines can be traced back to Dudwell. This sharp division has also been noted elsewhere, for example Starlings feeding at the village end of the Trecwn valley fly to Dudwell but those feeding at the Llanychaer end head for the Preseli roost. It is not known whether individuals remain faithful to a particular roost. The numbers using the roosts can be considerable, at least 200,000 having been estimated at the Preseli roost, and rough counts made at Dudwell suggest a total of two million Starlings assemble there.
Cold weather advancing from the east causes large numbers of Starlings to move through and to Pembrokeshire. Prolonged bad weather sometimes causes extensive mortality. Most movements are towards the west and are sometimes heavy; for example, birds passed at a rate of about 1,000 per 15 minutes at Marloes in January 1952 (Conder 1954) and over 52,000 passed over Milford Haven in 41/2 hours on 14 January 1987, an average of nearly 3,000 birds per 15 minutes.
Spring passage mainly takes the form of a fairly sudden departure, which is presumably nocturnal, during March. Starlings have been recorded at the lantern of the Smalls lighthouse throughout March and in early April. Night observation by radar, conducted near Tenby in March 1968 (Johnson 1969), recorded a strong passage of starling-sized birds overflying Pembrokeshire from north-west to south-east, consistent with through passage from Ireland.
CONDER, P.J. 1954. Weather movements at Dale and Marloes, Pembrokeshire. British Birds 47: 349—350.
JOHNSON, A.L. 1969. Radar observations of bird migrants in south-west Wales. Nature in Wales 11: 121-125.