Green Sandpiper - spring

Tringa achropus

Departure of over wintering birds from the main localities have been recorded up to late April and early May. Assessing spring passage has therefore not included records of this nature. Away from these wintering sites spring passage has been noted in 21 years between 1952 and 2006, so it has not been an annual event. Records have come from Skokholm, Skomer, Pembroke Mill Ponds, St David’s airfield, Tretio, Pen Beri, Gann, Teifi Estuary, Treffgarne, Ritec and Fortune’s Frolic. They occurred between March and 22nd May and involved single birds, except for two at St David’s airfield on the 7th April 2003 and two at the Gann on the 29th April 2001.

Graham Rees.

(Covers records up to and including 2006).

Green Sandpiper - autumn

Tringa achropus

Females tend to leave the breeding grounds early, about a third of the way through June, small chicks being left in the care of the males. Autumn passage in Pembrokeshire has commenced from the 20th June and continued to October, representing 65 % of the annual totals. Earlier birds were recorded at the Teifi Marshes on the 13th June 1990 and 2nd June 1996. One individual was reported as summering at the Teifi Marshes in 1994, being present from May to August.

Conceivably some November occurrences could have been late migrants but October has been used as a cut off point in this assessment.

Autumn passage totals 1990 – 2006.

These are minimum figures, for no means have been found for evaluating turnover of individuals at each site. Most records refer to one to four birds per occasion but up to five have been recorded at Skokholm, Eastern Cleddau and Heathfield Gravel Pit, six at Skomer, Teifi Marshes and the Gann, seven at Westfield Pill and nine at Pembroke Mill Ponds.

Graham Rees.

(Covers records up to and including 2006).

Sanderling - passage

Calidris alba

Autumn passage has been recorded from the 16th July to the end of November. The most favoured localities have been the Teifi Estuary (max. 15 on the 21st August 1987), Nevern Estuary (max. 18 on the 29th July 2005), Angle Bay (max. 25 on the 22nd September 2006) and Frainslake (max. 57 on the 21st July 1996). Transient birds have also been seen at popular bathing beaches, mostly involving one to four birds at a time but 12 were at Broad Haven (North) on the 2nd September 1985 and 50 there on the 30th July 1986.

Spring passage has been recorded from April to the end of June, most passing through during May, hence being a much quicker event than autumn passage and in terms of volume involving about half the number of birds.

The same localities were frequented in spring as in autumn, flock sizes being similar, the maximum recorded being 40 at Frainslake on the 18th May 1996.

Cumulative passage totals 1980 – 2006.

Graham Rees.

(Covers records up to and including 2006).

Black Tern - Spring

Chlidonias niger

Very few Black Terns have been recorded in Pembrokeshire in spring, viz. one at Dale on the 8th May 1954, two Teifi Marshes on the 7th May 1986, one Gann 19th April 1987 with three at nearby Anchor Hoaten the same day, one Skomer 24th April 1988, two Garron Pill 3rd May 1988 with one remaining for the next day, singles at Pembroke Mill Ponds 25th April 1988 and St Govan’s Head 20th April 1992.

Graham Rees

(Covers records up to and including 2006).

Black Tern - Autumn

Chlidonias niger

Autumn records spanned from the 8th August to the 11th November, 95 % of them between the 14th August and the 8th October. In some years few were seen, in others larger totals, especially when peak numbers passed in one or two days, as 100 on the 12th September 1981, 98 on the 14th August 1985, 112 on the 27th August 1997, 86 over the two days of the 24th and 25th August 1999, 97 on the 8th October 2001, 536 on the 31st August 2005 with 117 on the 1st September 2005.

The peaks occurred during brief periods of light to brisk southerly winds, particularly from the south east, accompanied by low cloud and mostly with rain or drizzle. On those occasions the terns flew in from out to sea flying directly into the wind. When nearing the shore they mostly turned westwards, which enabled them to continue out to sea but some turned into Cardigan Bay. On the 31st August 2005 groups approaching the land bunched into tight formation and climbed rapidly, almost vertically, to disappear from sight into the low cloud cover. It seems likely they continued on their south east heading, going overland. BWP notes that Black Terns sometimes migrate at considerable height and the beginning of such action was probably witnessed at Strumble Head that day.

Black Tern - Status

 Chlidonias niger Annual passage migrant.

The Black Tern has a widespread breeding range embracing the North Americas, Europe and Western Asia. Most of those seen in Pembrokeshire probably originated in Scandinavia, Poland and the western region of the former Soviet Union. Birds from this area migrate to winter along the western seaboard of Africa, where they are mostly coastal and pelagic.

Mathew (1894) mentioned just two undated records for the county and Lockley et al (1949) added just one more, shot at St David’s in September 1904. Black Terns were recorded 19 times between the years of 1949 and 1980, involving a total of 53 birds, the maximum in a year being 12 at Skokholm on the 8th September 1958. Post 1980 the Black Tern proved to be a regular autumn passage migrant in variable numbers. Records came from the Teifi Estuary, Nevern Estuary, Fishguard Harbour, Newgale, Broad Haven (North), several places within the Cleddau Estuary, Manorbier, Tenby, around the islands of Ramsey, Skokholm, Skomer and Grassholm, from the Fishguard to Rosslare and Pembroke to Rosslare ferries and over fresh water at Bosherston and Newgale Marsh. However the majority, 94 %, were seen at the intensely watched Strumble Head.

Annual total number of birds, 1981 – 2006.

Arctic Tern

Sterna paradisaea

Passage migrant.

The Arctic Tern has a continuous circumpolar Arctic and sub Arctic breeding range, the nearest nesting in Wales being at Anglesey and in Ireland in county Wexford. The species winters as far south as the edge of the Antarctic ice and there are ring recoveries of Anglesey birds off South Africa and Australia.

Mathew (1894) stated that the Arctic Tern was “seen commonly on passage in spring and autumn”, but Lockley et al (1949) later noted that they were “no longer seen commonly on passage” and noted just three occurrences, singles at Goodwick on the 13th August 1935 and at Skokholm on the 8th June 1938, with 20 at Dale at the end of April 1947. Donovan and Rees (1994) considered the Arctic Tern to be sparsely recorded in spring when up to eight at a time were seen passing, mainly off the west coast and offshore islands, between the 13th April and the 23rd June, but more numerous in autumn, when up to 30 in a day passed between the 21st July and the 22nd November, principally seen off the north coast.

Any detailed assessment of the Arctic Tern’s status is limited by the fact that only a proportion of Common or Arctic Terns are identified to species, most being logged as “Common or Arctic” , usually expressed as “Commic Tern” . What can be gleaned is that 130 were recorded at Skokholm on the 1st September 1997 and that single birds were recorded away from the coast at Heathfield Gravel Pit on the 23rd September 1999, at Bosherston on the 8-9th May 2000 and at Llawhaden on the 11th May 2000. 

See also the account for Common or Arctic Tern.

Graham Rees.

(Covers records up to and including 2009).

Common or Arctic Tern - Autumn

Sterna hirundo/ paradisaea  

Many more pass through on autumn passage, July to October, than in spring, with occasional accumulations of 100 to 800 birds having been noted off St Ann’s Head, Skokholm, Broad Haven (north) and sea area between Point St John, St David’s Head and the Bishops and Clerks as far out as Bais Bank. However, the majority have been recorded passing along the north coast at Strumble Head. Normally up to 30 per day were seen but periodically larger passages occurred, the largest on record being 190 on the 11th September 1984, 458 on 2nd September 1988, 459 on 27th August 1990, 256 on 11th September 1992, 363 on 4th September 1997, 375 on 1st September 1998, 199 on 17th August 2002, 726 on 31st August 2005 (an additional 151 Common Terns identified as well) and 501 on 8th September 2009.

These large movements have occurred with moderate to strong south or south-east winds, usually accompanied by poor visibility due to rain or drizzle. The terns have arrived on a north-west to south-east track, suggesting they had come from the Wicklow coastal area. The exception was on the 27/8/90 when they arrived from a north-easterly direction, presumably caused by a previous accumulation in Cardigan Bay moving on en masse, there being a moderate south-west wind and good visibility at the time.

Many more Common than Arctic Terns are identified in the county, so probably make up the majority of reported “Commics”.

Graham Rees.

(Covers records up to and including 2009).

Common or Arctic Tern - Spring

terna hirundo/ paradisaea

Spring passage has been recorded from the 29th March to mid June, with stragglers to the end of June, the majority of birds being seen in late April and the first three weeks of May. Most were seen to the west of Skokholm, Skomer and Ramsey, with very few along the north coast but small numbers off the south coast. Most sightings were of one to five birds but up to 18 together have been seen. Those seen moving along the south coast could conceivably have continued their migration up the Bristol Channel and through the Severn valley.

Common or Arctic Tern - status

Sterna hirundo/ paradisaea

Passage migrant.

It is not always possible to separate Common from Arctic Terns in the field unless they are close and seen well. However, most observers still wish to record what they see and log these birds as either “Common or Arctic”, usually expressed as “Commic Terns”. The following is a review of such records.

 There has been a marked difference in the nature of spring and autumn passages. There are many breeding colonies of both species to the north and west of Pembrokeshire along the coastlines of both western Britain and eastern Ireland, which are probably the origin of most passing the county. Whereas there has usually been a strong passage of birds migrating southwards from these colonies in the post breeding season, comparatively few have been seen passing northwards on their way to the breeding grounds. Although there are juveniles as well as adults swelling the population in the autumn, this alone does not fully explain the discrepancy in the volume seen. It seems more likely that having spent a pelagic winter season most spring birds pass Pembrokeshire out of sight of land, which would explain why the majority that are detected are to seaward of the islands beyond the west coast and increasing numbers are seen from land further up the narrowing Irish Sea. It is interesting to note in this context that in the spring of 1984, when direct comparison was possible, twice as many were seen passing The Smalls compared to Skokholm. As with other species of migrant birds, spring passage is performed with a sense of urgency to reach the breeding grounds at an optimal time, so is a rapid event. By comparison autumn migrants do not need to travel to their wintering areas according to such a strict schedule, being able to pause and accumulate at rich feeding sources en route.

Eider - passage

Somateria mollissima

Eiders have also been recorded in transit in every month of the year, either flying past prominent headlands like Dinas Head and Strumble Head (1 to 19 at a time), past the islands of Ramsey, Grassholm, Skomer and Skokholm (1 to 15 at a time), or settled temporarily on the sea.

 The latter category has included 30 at the Green Bridge of Wales on 26th April 1984, 38 in Caldey Roads on 25th March 1998, 17 off Solva on 17th April 2001 and 40 off Porthgain on 29th December 2003.

The origin and destination of these birds is unknown but Pembrokeshire lies between the main Eider concentrations in Wales at Aberdysynni, Merrionydd, mean of 72 in 12 recent years, and the Bury Inlet, West Glamorgan, mean of 97 in the same period, so could conceivably involve interchange between these populations.

Eider - status

Somateria mollissima

Winter visitor and passage migrant.

The Eider has a circumpolar Arctic and sub Arctic breeding distribution, extending southwards to northern England and Northern Ireland. They are sedentary and dispersive.

The Eider was first put on record for Pembrokeshire by Mathew (1894) noting an immature male at Dale on the 18th January 1891. He also mentioned that Eiders had been shot at Stackpole and Pembroke but gave no other details. Next noted in 1952, Eiders have been recorded in most years since.