Riparia riparia – GWENNOL Y GLENNYDD – Breeding summer visitor and passage migrant. Not recorded in January and December
|Breeding possible||excluded from total|
|No of tetrads occupied||10 (of 478)|
|Percentage of tetrads||2.1%|
A common summer visitor to Mathew (1894) “nesting in banks, the sides of gravel pits and old quarries”. Lockley et al. (1949) noted the Sand Martin as a summer visitor to small colonies in river banks and gravel pits and as a passage migrant.
Colonies in Pembrokeshire today are found in river banks, such as the Western Cleddau, sand pits such as Dale and Gupton, quarries including Treffgame and sea cliffs such as Abermawr. The occupation of sites varies according to the availability of suitably exposed sandy faces. River bank colonies are prone to move, so as to occupy the bends where there has been a fresh bank fall caused by spate during the previous winter. Sites that were occupied in the past, such as Dale sand pit, have become disused as they have become unsuitable. Some sites are only used for second broods, such as the sand pit at Trecwn. The Breeding Birds Survey of 1984-1988 found a total of 72 pairs breeding in Pembrokeshire (see map).
The first Sand Martins generally arrive in Pembrokeshire in the last week of March, but in some years they can be as early as 10 March, and one was at Bosherston Pools on 23 February 1989. Passage continues throughout April and May, sometimes until mid-June. Most pass through coastal areas and the offshore islands. They can be seen coming in off the sea along the southern shores, coasting along the western seaboard and departing out to sea from the north coast. They frequently stop off to feed on the way, especially over fresh water, including Pembroke Mill Ponds, Marloes Mere and Trefeiddan where aggregations of up to 200 occur. The Sand Martin population crash of 1983-1984 (Mead 1984) resulted in far fewer than normal passing through in the springs of those years, but there has been a steady revival in numbers since.
They begin to pass southwards on a broad front from July and continue until mid-September, numbers being smaller than in spring with usually less than 100 at any locality. Stragglers continuing up to 26 October are not rare, and one was seen at Bosherston Pools on 4 November 1986.
MEAD, C. 1984. Sand Martin slump. BTO News 133.