Sooty Shearwater - 1949

Puffinus griseus

Not mentioned by Mathew.  Seen fairly regularly migrating north-westwards during the early part of September off Skokholm.

R.M.Lockley, G.C.S.Ingram, H.M.Salmon, 1949, The Birds of Pembrokeshire, The West Wales Field Society

Sooty Shearwater - 1994

Regular autumn passage migrant. Has not been recorded in February, June or November.

This bird was not mentioned by Mathew (1894), but Lockley et al. (1949) regarded it as fairly regular during the early part of September, and Saunders (1976) assessed it as annual in its occurrence off the coast in extremely small numbers. The records for the 1950s to 1970s are predominantly from the Skokholm area and average three birds per autumn, with a maximum of six in 1970 and 1971.

Regular and frequent observation from Strumble Head during the 1980s has shown that far more than this pass southwards each autumn, an average of 81 per year being seen between 1983 and 1987. This figure excludes sharp daily peaks in passage occurring after south­west gales, when Sooty Shearwaters were presumably diverted downwind into Cardigan Bay but beat back out to sea in procession when the wind veered to north of west. Greater numbers pass Strumble Head in such circumstances, 237 on 1 September 1985 and 397 on 3 September 1983 being the largest counts. The passage period extends between 3 July and 30 October, but single birds have been seen off the Smalls on 22 March 1984 and off Strumble Head on 2 January 1988, 3 May 1982 and 23 December 1983, suggesting a few remain to winter in the northern hemisphere.

Sooty Shearwater - analysis

Puffinus griseus

The number of Sooty Shearwaters seen has been dependent on the nature of the weather systems occurring during the peak passage time, August to September. A trickle of small numbers were recorded during light to moderate winds, larger numbers in more turbulent weather.

During the 1980’s Atlantic depressions moving south-west to north-east with their centres passing over Northern Ireland and Scotland were prevalent. Locally these produced south-west gales which veered north-west before moderating when the system progressed further to the north-east.

The south-west component is thought to have displaced shearwaters from the Western Approaches into the Irish Sea. They were able to make their way back southwards when the wind wore around to the north-west, many of them passing close in to the north Pembrokeshire shore in the process. The largest counts of Sooty Shearwaters at Strumble Head were made during these conditions, i.e. 237 on the 1st September 1985 and 397 on the 3rd September 1983.

The depressions that occurred in August and September between 1990 and 2006 tracked further south with their centres over Pembrokeshire or further to the south. These systems did not produce the south-west going north-west winds locally, indeed they often produced easterly winds which did not prove favourable for placing Sooty Shearwaters in Pembrokeshire waters.

They did occasionally produce strong north winds blowing through the North Channel and down the Irish Sea, which pushed some Sooty Shearwaters close to the north Pembrokeshire shores but in lesser numbers than during the 1980’s. Counts between 11 and 35 were made on peak days, the maximum being 42 on the 14th September 2004.

Breakdown of Strumble Head totals

1980 - 89     1736

1990 - 99       645

2000 - 06       474

Graham Rees

(Covers records up to and including 2006)

Sooty Shearwater - status

 Puffinus griseus

Passage migrant.

The Sooty Shearwater breeds in New Zealand and its sub Antarctic islands, south west South America, the Falkland Islands, the South Atlantic islands and Australia. They spend winter in temperate sea areas in the North Pacific and North Atlantic. In the Atlantic they travel off the eastern seaboard of the Americas to the Newfoundland area, returning south off the western seaboard of Europe.

The Sooty Shearwater was first recorded in Pembrokeshire on the 9th September 1931 when R. M. Lockley saw one from a boat between Skokholm and Grassholm. Then Lockley et al (1949) stated “Seen fairly regularly during the early part of September off Skokholm.” 

A total of 41 were recorded between 1957 and 1978, most being logged at Skokholm but some were also noted off Skomer, South Bishop, from boats visiting Grassholm and the Smalls, from the Fishguard to Rosslare ferry and off Strumble Head.

They continued to be recorded on occasions at these places and also off St David’s Head, Ramsey, St Govan’s Head, from the Pembroke to Rosslare ferry, off the Swansea to Cork ferry and from small vessels visiting the Celtic Deep area. One to five birds per day were involved apart from 20 at the Celtic Deep on the 15th September 2002. However, much larger numbers were logged with greater regularity at Strumble Head between 1980 and 2006.

Overall annual pattern 1980-2006 at Strumble Head

 

(Expressed as the mean number of birds per six day periods. Values were adjusted for the seven day periods at the end of Aug and Oct by dividing their totals by seven and multiplying by six before calculating the mean.)

Passage has been recorded from the 3rd July to the 19th November, peaking in August and September but some sightings have been made outside this period. They were single birds at the Smalls on 22nd March 1984, at Whitesands Bay on the 28th December 2000, at Strumble Head on the 2nd January 1988, 3rd May 1982, 23rd December 1983 and 27th December 2006.

References

LOCKLEY. R. M, INGRAM. C. S. and SALMON. H. M.1949. The birds of Pembrokeshire, West Wales Field Society.