Sandwich Tern – 2007

Sterna sandvicensis – MOR-WENNOL FWYAF – Passage migrant. Not recorded from December to February

Sandwich Terns breed on the coasts both sides of the Atlantic, the Mediterranean, Black Sea and Caspian Sea. Those from the north-west of Europe winter mainly on the west coast of Africa.

The Sandwich Tern was a rare visitor to Wales up to the early 20th century. It was first recorded in Pembrokeshire when Bertram Lloyd saw four at Newport on the 3rd June 1928. Variously one to eight birds were then recorded in nine years up to the end of the 1970’s and from the 1980’s onward they were noted frequently each year on both spring and autumn passage.

Spring passage

Spring passage has been documented from the earliest recorded on the 8th March through to the 30th June. Records have involved sightings of from one to twenty birds at a time all around the coast, predominantly from the south coast and the west coast including the offshore islands, with far fewer noted along the north coast. Largest counts were of 22 at Caldey, 33 at Penally, 37 at Lydstep, 25 at Frainslake, 25 at the Gann and 21 at Fishguard Harbour. The general movement northwards to breeding colonies along the coasts of the Irish Sea and further up the west coast of the UK, to some extent makes the north Pembrokeshire coast  a lee shore and probably accounts for lesser numbers occurring there compared with the west coast and islands. It is speculative whether those accumulating along the south coast later move to the Irish Sea to continue their migration, or whether some may follow the shoreline of the Bristol Channel to cross overland to the North Sea. 

Autumn passage

Autumn passage has been numerically greater than that of spring, logged between 1st July and the end of October, with 11 November sightings, the latest on the 28th. Taking the break point between spring, 30th June, and autumn, 1st July, is debatable but the latest mean June date is the 22nd and the earliest mean July date is the 9th. Peak passage has consistently occurred between the 25th of August and the 30th September.  The graph shows the average no of sightings per week.

Strumble Head, mean day counts for peak period, 1980 – 2007.

The heaviest passage has been recorded along the north coast and this has been well documented at Strumble Head, where annual totals logged have varied as follows:

Strumble Head autumn totals 1980 – 2007.

Although passage birds normally moved steadily along the north coast, there have been occasional accumulations for short periods, such as 60 in the mouth of the Teifi Estuary, 42 off the Nevern Estuary, 150 in Fishguard Harbour and 250 between St David’s Head and Ramsey. Most have dispersed out to sea once clear of the Bishops but some have moved along the west coast, with up to 32 being logged at Skomer and 40 at the Gann and along the south coast up to 23 have been recorded at Tenby and Saundersfoot, with up to 40 at Wiseman’s Bridge.

The furthest recorded inland was one flying over Roch on the 21st September 1984 but they have several times been seen leaving Fishguard Harbour heading overland above Goodwick Moor. Although regularly seen inside the Cleddau Estuary, particularly at the Gann, in Dale Roads and Angle Bay, the only records from further upstream have been singles at Llanstadwell on the 9th July 1985 and 4th September 1985, two at Newton Noyes on the 2nd October 1985 and 10 at Landshipping on the 2nd October 2004 with 30 there on the 13th September 2006.   

Graham Rees. Pembrokeshire County Bird Recorder 1981-2007

More about the Sandwich Tern in Pembrokeshire