Calidris canutus – PIBYDD YR ABER – Winter visitor and passage migrant. Not recorded in June
The Knot has a circumpolar Arctic breeding distribution and winters in temperate and tropical areas. International studies have established that most Knots occurring in Britain are of the race islandica, which breeds in Greenland and the Canadian Arctic.
The nominate race canutus, breeding in the Old World Arctic, could conceivably occur occasionally in Pembrokeshire, perhaps in those years when there is a large influx of Little Stints and Curlew Sandpipers which share a similar breeding range.
Mathew (1894) considered the Knot to bean autumn and winter visitor to Pembrokeshire, appearing on the flats and oozes at the end of August and beginning of September. He gave no indication of the numbers involved but noted it as being seen commonly every autumn near Pembroke, also on the sands at Goodwick.
Lockley et al (1949) also classified the species as an autumn and winter visitor, usually seen in small parties of less than 20 birds but occasionally in larger groups, noting 100 at Dale on the 6th November 1938.
Post 1949 the Knot has principally remained an autumn migrant but has overwintered and there has been a small and regular spring passage.
All records have been from coastal areas bar one inland at Wallis Moor on the 23rd April 2002. Most have been seen at the Cleddau Estuary, with smaller numbers at the Teifi and Nevern Estuaries and Fishguard Harbour. They have also been seen on many of the beaches and by coastal pools, including those on the offshore islands, and one frequented the runways of the old Dale airfield in September 1983.
A small volume spring passage has been detected between March and the 30th May. The majority of the records involved up to four birds at a time but seven were at the Gann on the 22nd April 1990, 12 at Angle Bay on the 2nd May 1994, 19 at Frainslake on the 13th April 1996 with 39 on the 19th March 2006, 12 on the 9th April 2006 and 23 at nearby Blucks Pool on the 2nd April 2006.
A single laggard passed Strumble Head on the 2nd June 1997 which remains the only record in the county for that month.
Post 1949 the Knot has principally remained an autumn migrant, which has passed through from the 13th July to November, occasionally into December. Records have mostly involved one to 20 birds per occasion but 36 were seen at Angle Bay on the 23rd September 1999, 40 there on the 24th October 1963 and 43 on the 11th September 2000, 22 at the Gann on the 6th September 1991 and 24 at Frainslake on the 4th August 1997.
Flocks have also been noted moving southwards offshore which in all probability did not alight in the county and possibly not until they had reached France or beyond. This movement has involved 25 passing Ramsey on the 30th September 2001, 67 passing Skokholm on the 29th September 1958, 30 doing the same on the 25th August 1979 and a total of 2,742 logged passing Strumble Head in the autumn between 1983 and 2006.
The Strumble Head passages have been annual but variable, the fewest in a year being 21 in 1986, the most 578 in 1999. Groups of up to 20 birds were mainly involved but larger flocks were seen on many occasions, the largest being 85 on the 20th August 1983 and 90 on the 26th September 1996.
Knots were also recorded during a lighthouse attraction at Strumble Head in the early hours of the 25th September 1985.
Knots have long visited Pembrokeshire in the winter months of December to February but have only infrequently remained throughout those months.
They were recorded in every winter from 1983 to 2006 with the exception of 1992. Only one was reported in the winter in 1989, two in 1985 and five in 1986. Groups which did not stay for long were: 55 at the Gann on the 7th February 1954, 60 there on the 13th January 1963, 30 Pen y Cwm on the 27th January 1963 and 36 Furzenips on the 27th January 1996.
Even at the most favoured parts of the Cleddau Estuary, Angle Bay and the Pembroke River, they have seldom endured for long. The largest county presence of 500 at the Pembroke River on the 22nd January 1972 was only recorded on that date. A further 185 there in December 1999 had decreased to just nine by January 2000. Similarly 65 at Angle Bay in January 1987 had reduced to two by the 15th February.
Full overwintering has been recorded twice to date (up to 2006). About 85 were present from December 1996 to February 1997 using both Angle Bay and the nearby Pembroke River, whereas 24 at Angle Bay in December 2005 had increased to 70 by January 2006 with 80 by February.
It is established that Knots move between different estuaries in the UK during the winter in response to variable food availability, so it is possible that those occurring in winter in Pembrokeshire could have come from parts of Carmarthen Bay or the Burry Inlet, moving on if the local food supply was limited. This is speculation for there is no evidence that this happens, appropriate ring recoveries could provide confirmation.
Graham Rees (County bird recorder 1981 to 2007)
LOCKLEY. R. M, INGRAM. C. S. and SALMON. H. M.1949. The birds of Pembrokeshire, West Wales Field Society.
MATHEW. M. 1894. The birds of Pembrokeshire and its islands, R. H. Porter.