Osprey

Pandion haliaetus

Scarce passage migrant.

The Osprey has a worldwide breeding distribution, being absent only from the Polar regions. It is a summer visitor in temperate zones, north European birds wintering as far south as Africa.

The Osprey was formerly a rare bird in Pembrokeshire. Mathew (1894) knew of no occurrences but I. K. Morgan, while researching natural history matters in Carmarthenshire, unearthed the record of a specimen taken at Fishguard about 1842. It was documented in the unpublished papers of L. W. Dillwen. Another Osprey was recorded at the Pembroke River in 1904 (Lockley et al, 1949). Ospreys became extinct as a breeding bird in Britain post 1908 but began to recolonise Scotland in the early 1950’s. Numbers built up to reach 72 pairs by 1991 and 184 pairs by 2004. A few have nested in England and Wales.

Just one Osprey was recorded in Pembrokeshire during the time of breeding extinction in Britain, at the Pembroke River in September 1931. The re-establishment of the British breeding population had a discernable effect on occurrences in Pembrokeshire, being recorded in just one year in the 1960’s, then in two years in the 1970’s and in six years in the 1980’s. From the time that the Scottish population reached 50 pairs in the late 1980’s Ospreys became of annual occurrence in Pembrokeshire and the number of birds involved increased. 

Number of birds per annum, 1988 – 2006.

Most records refer to birds passing through but some have lingered at good food sources for days, more so in autumn than in spring.

Cumulative monthly totals, 1966 – 2006.

Spring records span the 4th March to the 28th June, autumn records from the 17th July to the 25th October, with a single occurrence in December at the Teifi Estuary on the 18th in 2000.

Attracted to waters where they can catch fish, Ospreys have been recorded from many places around the coastline, including the larger offshore islands, from all of the estuaries and from all the main rivers up to the headwaters, and bodies of water like Llys y fran Reservoir, Heathfield Gravel Pit and Clarydale, even prospecting small ponds at Troopers Inn and Wiston.

Graham Rees

(Covers records up to and including 2006).

References

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.

Great Northern Diver - spring passage

Gavia immer

Spring passage has been relatively small, mostly recorded as departure dates from wintering areas, normally completed by late March to early April. Occasionally presumed migrants have briefly appeared at some of these same places in late April up to 22nd May and others have been noted at or passing headlands and the offshore islands from late March to 26th May. Later occurrences were: one in the Gann – Lindsway Bay region throughout May until at least the 21st June 1991 and two at Ceibwr on 22nd June 1997. 

Great Northern Diver - autumn passage

Gavia immer

The variation in county annual totals seems to have had more to do with variation in the number of passage migrants recorded than with the number of wintering birds. Autumn passage has been noted along the coast and at the offshore islands, being most consistently documented at Strumble Head annually between 1983 and 2006.

The earliest recorded there was on 28th July 1991. August records were all of single birds, on the 31st in 1985, 24th in 1986, 28th in 1989, 23rd in 1994, 28th in 1994 and 27th in 1995. Numbers built up in September, the main passage taking place from October to December:

Totals have been grouped into six day periods, except that the last readings for October and December have been adjusted from seven day totals. This has been done by dividing the seven day totals by seven, then multiplying by six.

Great Northern Diver - status

 Gavia immer

Winter visitor and passage migrant.

The Great Northern Diver breeds across the sub Arctic region of the Americas, Greenland and Iceland and on rare occasions has bred in Scotland and as far east as Svalbard.  Those that winter in the east Atlantic do so as far south as the Bay of Biscay and Iberia.

As with many other species, it is difficult to assess the Great Northern’s status in Pembrokeshire in the past. The accounts of previous authorities have been largely anecdotal and prone to expressions like “sometimes numerous” and “frequently seen”.

Dickenson and Howells (1962) must have felt sufficiently able to interpret the past to state “From the numbers recorded in the last decade it is possible that a decrease has taken place since the 1930’s.” The decade they referred to was 1952 to 1961, when an average of three per annum was recorded, the maximum in any year being nine in 1959.

The average recorded per annum remained at three until 1982, the maximum in a year being six in 1972. By 1983 an increasing number of observers were putting the results of their observations into the communal record and from then until 2006 the average number recorded reached 61 per annum, with the most in a year being 119 in 1999:

There was a marked increase in the number of active observers during the 1980’s and 1990’s, they possessed ever improving optical aids and most had the discipline to contribute their observations to the communal record. These are likely to be the factors that explain the upsurge in records, rather than there being an increase in the number of Great Northern Divers visiting Pembrokeshire.

References

DICKENSON. H and HOWELLS. R. J. 1962. Divers in Wales, Nature in Wales 8.

DONOVAN. J and REES. G. 1994. Birds of Pembrokeshire, Dyfed Wildlife Trust.

LLOYD. B. 1929-1939 Diaries, National Museum of Wales.

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.

Black-throated Diver - passage

Gavia arctica

Donovan and Rees (1994) pointed out that the Black-throated Diver was a passage migrant as well as a winter visitor to Pembrokeshire. Passage has involved occasional birds flying southwards along the coastline and passing the offshore islands, mostly between September and December, although singles were recorded passing Strumble Head on 20th August 1997 and 21st August 1999 and one was at Lydstep Haven on 30th August 1988.

The number of migrants recorded has been small, with an average of nine per annum between 1983 and 2003, the most in any year being 29 in 1999. Passage has been well documented at Strumble Head, where the total between the years 1983 and 2006 is tabulated by month :

Sep - 8

Oct - 45

Nov - 85

Dec - 31

Most Black–throated Divers have departed the county by the end of March but there are 11 April records and four for May, the latest being one at Broad Haven (North) on the 25th in 1961, perhaps indicating birds passing through.

The Black–throated Diver has not been recorded in Pembrokeshire in June and July.

Graham Rees

(Covers records up to and including those for 2006)

White Wagtail - 1894

Species account from M Mathew, 1894, "The Birds of Pembrokeshire and its islands"

Click to read more ...

Pomarine Skua - spring passage

Stercorarius pomarinus

The Pomarine Skua has been of erratic occurrence in spring, involving small numbers between the 8th April and the 18th June. Singles have been recorded from Caldey, St Govan’s Head, Skokholm, Skomer, Grassholm, The Smalls, Druidston, Newgale, Ramsey and Strumble Head, with two together at Amroth on the 4th May 2003 and a party of five passed Skokholm on the 28th May 1991.

One seen at The Smalls on the 28th February 1983 may have been an early migrant or possibly over wintering in the general sea area.

Graham Rees

(Covers records up to and including 2006)

Pomarine Skua - autumn passage

Stercorarius pomarinus  .

The Arctic breeding range of the Pomarine Skua is almost circumpolar, being mainly correlated with the variable distribution of Lemmings. Migrants seen in north-west Europe are en route to or from wintering areas off west Africa, which lie largely north of the Equator.

The Pomarine Skua was first recorded for Pembrokeshire by Mathew (1894), who commented “a few are to be seen every autumn, and after heavy gales large flocks are observed.”  Lockley et al (1949) considered he could have been wrong, as they knew of only four occurrences during their time, the only one dated being on the 21st September 1930.

There were seven records involving 11 birds during the next 28 years. With the exception of 1979 they have been recorded annually since 1976. Most were seen in the autumn, between August and December and predominantly at Strumble Head.

 

N. B. The discrepancy between the 1991 total and that given by Donovan and Rees (1994) is because of additional records received since publication of that work.

Totals August to November 1980 – 2006.Values are expressed in six day intervals, the last period in months of 31 days have been adjusted from seven day totals by dividing by seven and multiplying by six.

Daily totals were small, normally involving less than 20 birds, with the following exceptions: 22 on the 20th October 1984, 30 on the 10th November 1985, 59 on the 7th October 1988, 97 on the 17th October 1991, 130 on the 18th October 1991, 20 on the 4th September 1992, 24 on the 20th October 1999, 27 on the 6th November 1999 and 21 on the 4th December 1999.

There were only six other bird days recorded in the month of December over the whole period from 1980 to 2006, the latest being on the 27th in 1990 and 1999. Early occurrences were of single birds on the 21st and 22nd July 1990 and 24th July 1998.

Away from Strumble Head, autumn records of one to four birds were noted off Fishguard, from the Fishguard to Rosslare ferry, Ramsey, Newgale, The Smalls, in the Celtic Deep, Skomer, Skokholm, St Govan’s Head and Amroth, with 11 at St David’s Head on the 5th November 1999.

Graham Rees

(Covers records up to and including 2006)

References

DONOVAN. J and REES. G. 1994. Birds of Pembrokeshire, Dyfed Wildlife Trust.

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

Red-throated diver - passage

Gavia stellata

A marked autumn passage of birds travelling from north to south has been recorded since at least 1980, spanning the months August to December, though singles were recorded in 2 years on the 11th July and once on the 3rd July.

This movement has been well documented at Strumble Head. August records were confined to the latter part of the month, 19th – 31st, totalling just six birds over the period 1980 – 2006.The main passage was between October and December and is represented below in graphical form. These are the mean annual values calculated from the total number of birds recorded for the period 1980 to 2006, grouped into six day intervals.

Only once in 27 years did the passage continue into January, when 40 passed on the 6th in 1991, thereafter no movement being detected during that month. The number of birds passing on any one day was generally small but over 30 was recorded five times in four different years, the maximum being 44 on the 4th December 1993.

The December peak was obscured in some years, with passage ceasing during gales. It is not known whether these held up birds within the comparative shelter of Cardigan Bay which continued their migration when the wind moderated, or the gales displaced birds from further south to seek shelter in the Bay, or possibly whether both reactions took place.

A passage of smaller volume than in the autumn has been noted in spring, March to 30th May. This has not been well documented but has involved birds passing westwards off St Govan’s Head, northward past the offshore islands of Skokholm and Skomer and eastwards past Strumble Head.

The Red – throated Diver has only been recorded in Pembrokeshire once in June, when two were seen at Skomer on the 18th in 2003.