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Home , Great shearwater, Sooty shearwater

British

Vol. 56 No. 6

JUNE 1963

The distribution of the Sooty around the British Isles By J. H. Phillips RECENT RECORDS of the (JProcellaria grised) from under-watched parts of the British coast can now lead us to an import­ ant reassessment of the status of this species. Its classification as a 'rather scarce visitor' in The Handbook (Witherby et al. 1940) and as an 'irregular visitor' in the B.O.U. Check-list (1952) was adequate accord­ ing to the records existing at those dates, but is by no means consistent with our present knowledge. This paper gives the main records of the species that have been made in the north-east Atlantic: the relation of its records and movements to oceanographic and meteorological conditions is being discussed elsewhere (Phillips 1963). The Sooty Shearwater is widely distributed over the Pacific and Atlantic oceans. Birds spending the non-breeding season (May to September) in the Atlantic, probably numbering only some tens of thousands, are derived from large colonies off Cape Horn, and from the . Kuroda (1957) has discussed the concept of a circular migration of the Tubinares around the world oceans, and it seems likely that Sooty reach the British Isles after moving up the east coast of and crossing the Atlantic between 450 and 6o°N. It is possible that this crossing is made only by those birds not breeding in the succeeding season.

MONTHLY DISTRIBUTION OF RECORDS Fig. i shows the known distribution of the Sooty Shearwater around the British Isles. There are few records in the north-east Atlantic outside the late summer and autumn. Stragglers have, however, been recorded off Britain in April (Sharrock 1962) and November (Temper- ley 1951) and at least three times in May (Boyd 1958, Kennedy et al. 1954, Rankin and Duffey 1948). The validity of Hiigel's (1869) record of a off Devon in February is uncertain. !97 BRITISH BIRDS

FIG. I . Records of Sooty Shearwaters {Procellariagrisea) around the British Isles. Areas in which the species occurs with fair regularity are shaded; single birds are indicated by a cross (x), and flocks by a filled circle (•)

198 SOOTY SHEARWATERS AROUND THE BRITISH ISLES June June is the earliest month in which any concentration of Sooty Shear­ waters has been observed over feeding grounds in the north-east Atlantic. Lockley and Marchant (1951) found a small concentration on the Rockall Bank towards the end of the month, with individual birds scattered towards the mainland. None was found there by Harvie-Brown and Barrington (1897) when they visited the area in the first half of the month. My Allison et al. (1952) saw small numbers at three stations between two and four hundred miles south of Iceland, including some near Rockall, in this month. There are several other scattered records, including several from the Hebrides (MacRae 1936) and from the coast of Brittany (Mayaud 1949). August The main dispersal of Sooty Shearwaters across the Atlantic occurs in August, and it is then that the species is first recorded regularly, and in fair numbers, in British waters. In the north-east Atlantic records extend from 75°N (Duffey 1951) to as far south as 37°N (Owen 1958). The principal records of concentrations of feeding birds, however, come from the Faeroes (J. J. Hatch in litt.*) and from the west coast of Ireland. Kennedy et al. (1954) reported that 'a large number' was seen off the Mullet peninsula, Co. Mayo, on 17th August 1911, and I saw fair numbers there associating with Manx Shearwaters (P. ) in the latter half of August i960 and 1961. Sharrock (i960,

*These records are unpublished. Mr. Hatch observed Sooty Shearwaters around a trawler in Faeroese waters on several days in August i960, the most being to the south-west of the Faeroes on 23 rd August, when there were always about twenty-five around the ship.

Fig. 1 is based on data from Clarke (1912), Evans (1903), Gibbs et al. (1954), Kennedy et al. (1954), Lockley and Marchant (1951), MacRae (1936), Nelson (1907), Rankin and Duffey (1948), Temperley (1951), and Ussher (1901, 1905); from other published sources not included in the detailed list of references, namely Baxter and Rintoul, Birds ofScotland (1953), Bolam, Birds oj Northumberland (1932), Boswall, Brit. Birds, 53: 212-215 (i960), Bourliere, L'Oiseati, 16: 42-60 (1946), Campbell, Brit. Birds, 30: 378 (1937), Chislett, Yorkshire Birds (1953), Fitter, Brit. Birds, 32: 399-400 (1939), Harber, Brit. Birds, 44: 315 (1951), Hartley, Brit. Birds, 31: 89 (1937), Lockley, North-western Nat., 298-301 (1932), MacFarlane and MacRae, Brit. Birds, 30: 324 (1937), Mayaud, Alauda, 10: 188-198 (1938), Nisbet, Brit. Birds, 47: 169-170 (1954), Richardson, Brit. Birds, 41: 314 (1948), Riviere, History of the Birds of Norfolk (1930), and White, Brit. Birds, 31: 230-232 (1937); from the journal and the Annual Reports of the Cornwall Bird- Watching and Preservation Society; from unpublished records of the Royal Naval Bird-Watching Society; and from unpublished personal observations. 199 BRITISH BIRDS 1962) reported similar numbers off Cape Clear, Co. Cork, at the same time. In addition, there are many records of single birds and small parties, especially from the Hebrides, the Firth of Forth and the Northumberland coast, and off south-west Cornwall.

September British records are most numerous in September. Their general distribution is similar to that in August, but in this month occasional birds are liable to be found all round the British coast. The main records again come from the west coast of Ireland and the north-east coast of England and . On the west coast Gibbs et al. (1954) counted 137 off Malin Head, Co. Donegal, on 9th September 1953. Further south, I saw Sooty Shearwaters on almost every day of watching from Erris Head, Co. Mayo, in the first half of September i960 and 1961, with up to two hundred in a day. Off the south-west of Ireland Becher noted flocks of Sooty Shearwaters in September 1900 and 1901 (Ussher 1901, 1905), and the presence of concentrations there at that time has since been amply confirmed by observations from Cape Clear, Co. Cork, where flocks of up to 350 have been reported (Sharrock i960, 1962). In the a flock of 5 00 Sooty Shearwaters, associating with 500 Manx Shearwaters, was seen off the Isle of May in the Firth of Forth on 25th September 1959 (Eggeling 1959). This is the largest concentration ever found in the north-east Atlantic. Evans (1903) also recorded large numbers in the Forth in September. Smaller numbers are found scattered down the east coast; Nelson (1907) summarised a quantity of records from Yorkshire, and Cudworth (1959) has provided some recent observations of fair numbers off Spurn Point: the peak of 43 on 16th September 1959 corresponded with a peak in numbers.

October By October most Sooty Shearwaters are departing from the North Atlantic. The majority of records still come from the British Isles, but these refer only to odd birds and, as in September, are from many parts of the coast. The only records of even small concentrations in the North Atlantic at this time come from Spain and Portugal.

DISCUSSION The Sooty Shearwater is principally an off-shore species (using the notation of Wynne-Edwards 1930). That is, it is a bird of the con­ tinental shelf, feeding on the rich fishing grounds found where the depth is, in general, less than 100 fathoms. This has been clearly demonstrated for Sooty Shearwaters off the western North American

200 SOOTY SHEARWATERS AROUND THE BRITISH ISLES coast (Yocom 1947), off Peru (Murphy 1936) and off South Africa (Stanford 1953), and by the fact that it is recorded rather infrequently on Atlantic transects. The species is a long-distance migrant and its ocean crossings are probably made rapidly; at other times it lingers on the feeding grounds off the continental land-masses. After crossing the Atlantic (mostly in August or early September) flocks congregate on the principal feeding grounds over the continental shelf in the north-east Atlantic. The species rarely reaches as far north as Iceland, but concentrations are found on the fishing grounds off the Faeroes and off north-west Britain. It is probably safe to say that these feeding birds are regular in some numbers in the Hebrides and off western Ireland each year: the lack of regular observation in these areas presumably accounts for the rather scattered nature of the records. They consume offal when this is available (Clarke 1912, Lockley and Marchant 1951), but probably feed mainly on fry, young Herrings (Clupea harengus) and possibly Pilchards (Sardina pikhardus). They have been observed feeding with flocks of Manx Shearwaters off Erris Head and off Cape Clear, and the unusually large numbers in the North Sea in September 1959 were also associated with this species. Sooty Shearwaters are regularly recorded on the north-east coast of Britain, where the observer density is much higher than in the west. However, records are comparatively rare from the south North Sea and English Channel. Thus Mayaud (1953) noted that the Sooty Shearwater, though regular in small numbers in Atlantic waters off the French coast from August to November, is rare in the Channel. There are also very few Irish Sea records, and it appears that the species tends to keep to the outer, Atlantic coasts of north-west Europe. Stragglers are always liable to appear in unexpected places, however. Thus there are four Danish records (Groth 1961), but all these are from the east coast, in November, December and January; a single bird has also been reported from Liibeck Bay in November (Brennecke 1959). Some interesting observations have been made on the direction of flight of Sooty Shearwaters. Nicholson (1952) postulated a migration route south through the North Sea and west through the English Channel, his evidence for this presumably being the records of Alexan­ der (1912, 1914, 1916) from Dungeness, Kent. However, it now seems very likely that these records in fact referred to Balearic Shear­ waters (P. puffinus mauretanicus) and they should be discounted (H. G. Alexander in lift.). The observations of northerly movement quoted by Cud worth (1959) from Spurn Point, Yorkshire, and those of westerly movement past Cley, Norfolk, made by R. J. Johns (in litt.) (quoted by Richardson i960), taken with the absence of records in the Channel, suggest that Sooty Shearwaters which enter the North Sea

201 BRITISH BIRDS generally leave it by moving north again and rounding the top of Scotland. Gibbs et al. (i 9 5 4), Pettitt (1960) and I have all found a south-westerly passage past north-west Ireland. Observations at Cape Clear, Co. Cork, however, indicate that considerable numbers pass this island, also heading south-west. Thus of 117 Sooty Shearwaters seen there in i960, only two were moving east (Sharrock i960), and of the very large number seen there in late August and early September 1961, the great majority were either moving south-west or were congregat­ ing in flocks in the area (Sharrock 1962). The species is, however, only rarely recorded off Great Saltee, Co. Wexford, and there is no southerly passage through the Irish Sea. It seems possible that there may be a build-up of Sooty Shearwaters around south-west Ireland before they head south for Biscay or Spain. Some birds heading south past western Ireland may, on 'overshooting' the limit of high off-shore plankton density, perhaps at about the 50-fathom contour, follow this to the east, spending some time off southern Ireland, where they have been recorded feeding in association with flocks of Manx Shearwaters in August, before heading south out to sea when meteoro­ logical conditions are suitable. Such a build-up of sea-birds would be analogous to that found, on a much larger scale, off California in autumn.

CONCLUSION The Sooty Shearwater is a regular autumn visitor to the British Isles, principally to Atlantic coasts, making a southerly movement past these during August and September. It is also frequently recorded off north-east Britain, but generally in smaller numbers except in unusual meteorological conditions.

REFERENCES ALEXANDER, H. G. (1912): 'Sooty Shearwater off Kent'. Brit. Birds, 6: 159. (1914): 'Unusual birds at Dungeness'. Brit. Birds, 7: 227. (1916): 'Birds at Dungeness in 1915'. Brit. Birds, 9: 272-273. ALLISON, F. R., DARLINGTON, A., BARRAS-SMITH, M. A., and ROMER, M. L. R. (1952): 'Bird observations on ocean -weather ships in 1950'. Marine Obs., 22: 27-32. BOYD, J. M. (1958): 'The birds of Tiree and Coll'. Brit. Birds, 51: 41-56, 103-118. BRENNECKE, H. E. (1959): 'Beobachtung eines Dunkles Sturmtauchers {Puffinus griseus) in der Liibecker Bucht'. Orn. Mitt., 11: 26-28. CLARKE, W. E. (1912): Studies in Bird Migration. London. CUDWORTH, J. (1959): 'Reports from bird observatories, autumn migration, 1959: 4. Spurn Point, Yorkshire'. Bird Migration, 1: 104-106. DUFFEY, E. (1951): 'Sooty Shearwater in the Barents Sea'. Brit. Birds, 44: 179. EGGELING, W. J. (195 9): 'Reports from bird observatories, autumn migration, 1959: 2. Isle of May, Fife'. Bird Migration, 1: 100-103.

202 SOOTY SHEARWATERS AROUND THE BRITISH ISLES

EVANS, W. (1903): 'The Sooty Shearwater in the Firth of Forth'. Ann. Scot. Nat. Hist., 12: 26-28. GIBBS, A., NISBET, I. C. T., and REDMAN, P. S. (1954): 'Birds of north Donegal in autumn, 1953'. Brit. Birds, 47: 217-228. GROTH, J. K. (1961): 'Sodfarvet Skrape (Puffinus griseus Gm.) i sydlige Lillebselt'. Dansk Orn. Foren. Tidsskr., 54: 199. HARVIE-BROWN, J. A,, and BARRINGTON, R. M. (1897): 'RockalT. Trans. Roy, Irish Acad., 31: 66-7 5. HUGEL, A. DE (1869): 'Ornithological notes from south Devon'. Zoologist, (2) 4: 1720. KENNEDY, P. G., RUTTLEDGE, R. F., and SCROOPE, C. F. (1954): The Birds of Ireland. Edinburgh and London. KURODA, N. (1957): 'A brief note on the pelagic migration of the Tubinares'. Misc. Rep. Yamashina's Inst. Orn. Zool., 11: 436-449. LOCKLEY, R. M., and MARCHANT, S. (195 I): 'A midsummer visit to Rockall'. Brit. Birds, 44: 373-383. MACRAE, A. (1936): 'Sooty Shearwaters and a off the Hebrides'. Brit. Birds, 30: 174-175. MAYADD, N. (I 949): 'Commentaires sur 1'omithologie francatse'. Alauda, 17: 79-94. (1953): 'Liste des oiseaux de France'. Alauda, 21: 1-63. MURPHY, R. C. (1936): Oceanic Birds of South America. New York. NELSON, T. H. (1907): The Birds of Yorkshire. Vol. 2. London. NICHOLSON, E. M. (1952): 'Shearwaters in the English Channel'. Brit. Birds, 45: 41-55- OWEN, J. (1958): 'Autumn migration in southwest Portugal, 1957'. Ibis, 100: 5^5-534- PETTITT, R. G. (i960): Tory Island i960: Second Report of the Tory Island Bird Observa­ tory. PHILLIPS, J. H, (1963): 'The pelagic distribution of the Sooty Shearwater Procellaria grisea'. Ibis, 105: in press. RANKIN, M., and DOFFEY, E. A. G. (1948): 'A study of bird life of the North Atlantic'. Brit. Birds, 41: spec, suppl., 42 pp. RICHARDSON, R. A. (i960): 'Reports from bird observatories, autumn migration, i960: 5. Cley and Blakeney, Norfolk'. Bird Migration, 1: 256-257. SHARROCK, J. T. R. (i960): Cape Clear Bird Observatory Report No. 2. (1962): Cape Clear Bird Observatory Report No. 3. STANFORD, W. P. (1953): 'Some sea birds in winter off the southwest Cape'. Ostrich, 24: 17-26. TEMPERLEY, G. W. (1951): A History of the Birds of Durham. Durham. USSHER, R. j. (1901): 'Great and Sooty Shearwaters on the south coast'. Irish Nat., 10: 42. • (T9°5): 'Great and Sooty Shearwaters in 1901'. Irish Nat., 14: 43. WITHERBY, H. F., JOURDAIN, F. C. R., TICEHURST, N. F., and TUCKER, B. W. (1940): The Handbook of British Birds. Vol. IV. London. WYNNE-EDWARDS, V. C. (1930): 'Birds of the Nordi Atlantic'. Discovery, 11: 359-362. YOCOM, C. F. (1947): 'Observations on bird life in the Pacific ocean off the North American shores'. Condor, 49: 204-208.

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