an historical and personal - british birds

504 British Birds 92: 504-518, October 1999

BRITAIN AND

IRELAND’S FIRST

‘SOFT-PLUMAGED PETREL’

— AN HISTORICAL AND PERSONAL

PERSPECTIVE

J. W. ENTICOTT

ABSTRACT Details are presented of the first temperate NorthAtlantic sighting, in 1974, of a ‘Soft-plumaged Petrel’ (i.e. MadeiraPetrel Pterodroma madeira or Cape Verde Petrel P. feae)1. Thedifficulties and problems encountered at the time through lack ofknowledge of the species are discussed, as are data on specimens atthe Natural History Museum, Tring. Changes in taxonomicthinking and the consequent improvement in knowledge and fieldidentification are outlined chronologically. A possible mechanismby which seabirds cross the North Atlantic is discussed, andpreliminary conclusions regarding the increased number ofsightings of ‘Soft-plumaged Petrels’ are made. The Irish Rare BirdsCommittee also comments on its initial appraisal and subsequentreassessment of this record.

This paper is dedicated to the memory of Clive Hutchinson, whom I first met on Cape Clear in August 1966—we were the same age.

1 In 1974, ‘Soft-plumaged Petrel’ consisted of nominate P.m.mollis from the Southern Ocean; P.m.madeirafrom mainland Madeira (since 1983, known as Madeira Petrel or Zino’s Petrel P. madeira); and P. m. feaefrom Bugio in the Desertas Islands (previously P. m. <deserta>) and the Cape Verdes (since 1983,together known as Cape Verde Petrel or Fea’s Petrel P. feae). Consequently, all ‘pre-1983’ North Atlanticrecords are referred to here as ‘Soft-plumaged Petrel’ (involving either madeira or feae, but not nominatemollis). The validity or otherwise of southern P. m. dubia is outside the scope of this paper.

Cape Verde Petrel (Keith Shackleton)

British Birds 92: 504-518, October 1999 505

BRITAIN AND IRELAND’S FIRST ‘SOFT-PLUMAGED PETREL’

The establishment of a bird observa-tory on Cape Clear Island, Co. Cork,Ireland (fig. 1), in 1959 soon indi-

cated that the potential for observingoceanic petrels and shearwaters (Procellari-iformes) at certain times of the year, and incertain weather conditions, was immense.Systematic seabird observations from CapeClear Island over a period of years estab-lished patterns of occurrence which weresometimes wide-reaching, especially in a‘European’ context. Preliminary results forthe Observatory’s first 11 years were sum-marised by Sharrock (1973) and Bourne(1973).

Akin to these movements, occasionalsightings of rarer, more southerly Procel-lariiformes were made from Cape ClearIsland. Sharrock & Sharrock (1976) pre-sented quantified data (1958-72) in a widergeographical context on Black-browedAlbatross Diomedea melanophris, Wilson’sStorm-petrel Oceanites oceanicus and Cory’sShearwater Calonectris diomedea thatshowed the importance of Cape ClearIsland in particular and southwest Irelandin general. It soon became apparent that alink with the Lusitanian fauna extended toseabirds, as well as landbirds.

As an impressionable teenager, I wit-nessed some of these seabird movementsin the 1960s and soon became hooked onthe island’s potential. In 1973, I spent most

of the summer off the south and westcoasts of Ireland, working on trawlers, aswell as carrying out land-based sea-watching from Cape Clear Island; in thatyear, vast numbers of Great ShearwatersPuffinus gravis (14,374 from 3rd August to18th September; majority 1st-10th Sep-tember) were recorded from Cape ClearIsland, with smaller numbers of Cory’s andLittle Shearwaters P. assimilus and storm-petrels (Hydrobatidae).

In 1974, when my time was morelimited, I concentrated on intensive sea-watching from the island, arriving on 1stSeptember. Despite high expectations, thefirst four days were relatively quiet byCape Clear standards, with no Cory’sShearwaters and very few Great Shearwa-ters. There were typical westwardmovements of Manx Shearwaters Puffinuspuffinus, Fulmars Fulmarus glacialis andNorthern Gannets Morus bassanus, withfewer Sooty Shearwaters P. griseus andstorm-petrels. The heaviest movement wason the morning of 2nd September, with apassage of about 2,000 Manx Shearwatersper hour, but this had decreased markedlyby midday; this movement was probablythe result of a deep depression (972 mb)passing over Cape Clear on that day. Inter-estingly, on 2nd September, at ClogherHead, Co. Louth, Moore (1975) recordedthe only northward movement of ManxShearwaters that autumn, totalling 11,000birds from 13.30 to 16.30 hours (as well asabout 100 Fulmars per hour), after 12 hoursof gale-force winds; he suggested thatthese observations agreed withManikowski’s (1971) theory that pelagicbirds move ahead of advancing low-pres-sure systems. This vigorous depression,which had moved 500 miles (800 km) in 24hours, also resulted in an increase in storm-petrels at Cape Clear on 4th September, to140 per hour moving west past Blananarra-gaun tip, as well as the first of a series ofalmost daily immature Sabine’s Gulls Larussabini.

On the morning of 5th September, lowcloud from a weak front had gradually

Figure 1. Location of Cape Clear Island.



the sun was shining, giving the choppy sea adeep green colour which was good both forseeing birds at distance and for discerningcolour. As this bird approached, I immediatelythought Great/Cory’s, but size and colour didnot fit and the presence of a completely darkunderwing implied something completely dif-ferent. The bird was observed for about 2 minsin excellent light until it passed Blanan’;however, from Blanan’ west, rain had started tofall and the sea colour was much greyer.

The following notes were made imme-diately after the bird had disappeared:

16.30. From 1,000 m to 600 m at closest thenflying W. Impression of smallish Great Shear-water, but size difference, wandering flight anddark underwing. Upperparts greyish-brown,more brown than grey, perhaps more recalling apale Cory’s—light good at time (sun), thusbrowns appearing richer but not contrasting asManx in sun (brown mantle/black primaries) orSooty (rich dark brown).

Underparts clean white. Problem of under-wing—completely dark, not light middle anddark border as Great/Cory’s; all dark—more sothan upperparts—sooty blackish.

Tail as upperparts—no white rump or darkertail or darker wing tips as Great/Cory’s wouldcertainly [show] in this light: thus uniformupperparts.

Head as upperparts, possibly slightly darker,but no definite cap as Greats, but distant.

Size—slightly smaller than Sooty—nearerSooty size than Manx (both present).

Wing shape—Sootyish—quite long butnoticeably narrow. Distinct curve from carpal towing tip giving very pointed effect. Wings held

back from body and slightcurve to carpal joint frombody—generally like arough-weather Sooty but notso pronounced.

Flight—beats 4, quitequick, but rambling andambling over waves onslightly bowed wings, effort-less. Wide zig-zag path oftenbanking without flaps. Quitehigh at times (c. 15 ft [4.6m]). Very buoyant in the air(‘butterfly-like’: P. Ewins)and extremely agile as ifJ.W. Enticott’s sketches of bird, with Sooty Shearwater for comparison.

lifted by 09.00 hours. Observation during07.30-10.00 from Pointabullaun, however,produced only typical numbers of ManxShearwaters, Fulmars and NorthernGannets, although storm-petrels weremoving west at about 50 per hour andSooty Shearwaters at ten per hour.Returning to the top of Blananarragaun at15.30, Chris Cook, Pete Ewins and I com-menced an hour’s systematic seawatching,which produced storm-petrels at about 110west per hour, with only a few SootyShearwaters: not much different from themorning. I started thinking of a welcomepint of ‘Murphy’s’ in Paddy Burke’s barwhen I suddenly picked up a seabirdapproaching Blananarragaun at a distanceof about 1 km. I could not place this bird atall; it was new to me and was completelydifferent from anything I had seen before,and I alerted my companions to it.

OBSERVATIONS AND NOTESThe following notes and sketches wereentered into the log and on individual‘Unusual Record’ forms by all threeobservers. The notes are reproduced herewith only minimal subediting.

At the very end of an hour’s watch from Blanan’top, my attention was drawn to what I thoughtwas a largish shearwater gradually approachingBlanan’ from the east. This was at 16.30 hrs andthe preceding hour had produced little of note:several Sooties and a petrel passage at 1-2 milesof 110 per hour.

Although rain was imminent from the west



gaining lift without beats of shearwater-zig-zag. No ‘hovering’ and arcs much wider thanrough-weather Sooties.

Sooties not flying in arcs as in roughweather—several quick beats (much moreoften) then 45° to horizontal glide but lowand not in arcs.

Flying into SW 3–4 wind but verychoppy sea. Watched for 2+ mins as gradu-ally W, no concern for food or other species,light excellent at first in deep green sea (sunout); rain when bird off Blanan’ point, butstill visible in greyer conditions as gradually Wto Fastnet, still banking (undertail-covertswhite—P. Ewins).

The bird was well seen in good light, and themost distinctive feature was the flight and theapparent ease of covering such a long distancewithout wing-beats. When passed Blanan’ thebird momentarily turned eastwards before con-tinuing west.

The plumage features were well seen and thesuperficial colour resemblance to Great/Cory’sseems significant. The demarcation about thehead was probably similar to Manx demarca-tion, and there was no cap of a darker colour nordistinct collar as Great Shearwater.

The curvature of the front part of the winggave a storm-petrel effect, and the narrowness ofthe wing even more so than Sooty gave a scythe-like effect. Compared with the flight of this bird,Sooties appeared to be labouring into the wind,having to flap every 10-15 ft [3-5 m], and Manxwere gliding at 45° only, again with much flap-ping.

From the reference books available all‘British’ seabirds can safely be eliminated, and itseems conceivable that this bird was possiblyone of the Pterodroma genus of petrels. It seemsdoubtful if identification can be taken anyfurther, though surely the flight is distinctenough to give an indication.J. W. Enticott

Jim Enticott drew my attention to an ‘odd’shearwater flying low over the sea off Blanan’point. My first impression was of a skua [Sterco-rariidae], but I soon dismissed the idea onfurther observations of mode of flight andplumage.Flight: The pattern was similar to a ‘bob-sleigh’,the bird moving forwards in a zig-zag manner,banking at the extremities of the zig-zag, andflapping on only two occasions, each comprising

4-5 wing beats (the beats being slower thanManx Shearwater, and more determined). As theextremity of the zig-zag was reached, the birdseemed to lose speed slightly, and then gain itsoon afterwards. The flight was buoyant and\somewhat reminiscent of a butterfly (cf. WhiteAdmiral [Limenitis camilla])—although flappingof wings was absent.Size and form: Slightly smaller in all dimen-sions than Sooty Shearwater. Wings striking inthat they were proportionately ‘long and thin’for the body-size. The wings were also notice-ably thin for the length of wing. The primarieswere curved downwards—this feature beingobserved when the bird was gliding away fromus and we saw it in a ‘rear-end’ profile. Thewing-tips were held back (from the carpal to tipsof primaries), giving a skua-like appearance, anddid not resemble any shearwater I have seen asthe degree of ‘backward sweep’ was muchgreater than in Sooty or Great. The structure ofthe head and tail were not observed sufficientlywell to merit any description, this due to the dis-tance, even though light conditions wereexcellent.Upperparts: brown/dark grey, showing novisible contrast, and this general upper col-oration extended onto the nape and crown, butthere was certainly no dark-capped appearance.The tail was not seen clearly, but certainly noprominent field mark was present on the brownbackground colour (such as a white rumppatch).Underparts: Underside of wings appeared uni-formly dark brown, contrasting markedly withthe pure white breast, belly, flanks and under-tail-coverts. No wing flashes or hint of wingflashes were observed, and the bird passedthrough a party of feeding Gannets undeterredby their presence. No call was heard, and thebird did not stop to feed.Peter Ewins

Peter Ewins’ sketch of underside of bird in flight.



JWE pointed out a bird flying low over the sea.At first he thought Great/Cory’s and, as I hadn’tever seen large shearwaters before, it wasn’tmany seconds before my binoculars weretrained on it. The bird was in view for about 2minutes at a range of approx. half a mile. Thesea was in a roughish condition and the colourwas greenish, good for seeing birds against.Upperparts: dark, probably brownish/black.Underparts: White. The underwing was com-pletely dark, nothing like the underwings ofManx or Sooty Shearwaters.

I didn’t see anything of the head or tail end.Wings were quite long, giving the bird a ‘thinbelly and long-winged appearance’. The bird inflight resembled a Sooty with the wings arched.It would flap about 4-5 times and then glide fora short distance. While it was gliding it zig-zagged and turned back the opposite way.Sometimes it banked, then you could see theundersurfaces of the wings, which were dark.The wings were very pointed and held at a back-ward angle when gliding.Chris Cook

POST-OBSERVATIONDEDUCTIONSAs we returned to the Observatory, stillsuffering from shock and disbelief at whatwe had seen, we met Steve Yeo and IanBurrows on the Low Road. It soon becameapparent that this was no ordinary seabird,especially in view of its manner of flight.Reference literature at the Observatory atthat time was scant, but we eventually nar-rowed the bird down cautiously to one ofthe southern Pterodroma petrels, most prob-ably ‘Soft-plumaged Petrel’ (see footnoteon page 504), although, from the limitedliterature and illustrations available, thatspecies should have shown a breast band.

Whether the bird was identifiable or notwas somewhat overshadowed by the factthat the only previously recorded Ptero-droma in Britain and Ireland was a CappedPetrel P. hasitata, caught on a heath nearSwaffham, Norfolk, in March or April 1850(Newton 1852; Hollom 1960; BOU 1971).Very suddenly, ‘Murphy’s’ in Burke’s Barbecame a necessity!

Further seawatches on 6th Septemberproduced little of note, with the possibleexception of one Great Shearwater, but byevening storm-petrels were moving west ata rate of about 250 per hour. On the fol-lowing day, Cape Clear Island was hit bywhat was either the remnants of a hurri-cane or, more probably, an extremely deepdepression. Winds were force 11-12, andthis was, by far, the roughest day I haveever experienced on the island; there wasdamage to the Observatory and otherbuildings. Unfortunately, attempts at sea-watching were uncomfortable, impossibleand unproductive. The day of 8th Sep-tember was calmer, but still producednothing unusual.

RESEARCHI left Cape Clear Island on 9th September,going via Akeragh Lough in Co. Kerry(where I saw a Wilson’s PhalaropePhalaropus tricolor, Irish Bird Rep. 22: 14) toarrive on 12th at Dublin, where I embarkedon the SS Nevasa bound for the Atlanticseaboard of France, Spain, Portugal,Gibraltar and then Madeira. During thecourse of this voyage, I saw and pho-tographed numerous seabirds new to me,including Madeiran Storm-petrel Ocean-odroma castro and Bulwer’s Petrel Bulweriabulwerii. The problem of the identity of theCape Clear Pterodroma was solved on 21stSeptember, when I saw and photographedseveral groups of ‘Soft-plumaged Petrels’at sea, within sight of Madeira. I tookextensive field notes on these birds,recording that they did not possess thecomplete breast band illustrated in Shack-leton & Stokes (1968). Alexander (1963)stated that ‘underparts sometimes dark

Chris Cook’s sketch of underside of bird in flight.



grey, usually white with a band of slate-grey, often not quite complete across thechest’, but provided no illustration.

Following up on the limited publisheddata available, I made visits to the NaturalHistory Museum, London, for a literaturesearch and then to the British Museum(now Natural History Museum), Tring, toexamine specimens. Through the courtesyof Dr David Snow, I was able to examineand measure 26 specimens of ‘Soft-plumaged Petrel’ and to assess thevariability of the breast band (see table 1).

Although a sample size of 26 is small, itseemed that a complete breast band wasmore common on southern populations,which may show a complete or an incom-plete band, whereas northern populationshad an incomplete breast band.

I wrote to the Meteorological Office,Bracknell, Berkshire, for copies of weathermaps for the North Atlantic for the period29th August to 6th September 1974. Theseproved very interesting with regard to themovement of deep depressions and/orhurricanes across the North Atlantic abovethe Azores high-pressure zone. In addition,Mr A. W. E. Barber from the Met. Office

provided a complete breakdown of themovements and details of Hurricane‘Becky’, which crossed the North Atlanticfrom west of Bermuda (28th August) to43°N 35°W (16.00 GMT on 2nd September),and to 44°N 20°W (06.00 GMT on 4th Sep-tember), some 600 miles (960 km)southwest of Ireland, by then downgradedto a deepening depression.

Finally, in early 1975, I sent a completeset of field notes to two leading seabirdexperts, Dr W. R. P. Bourne and Dr J.Warham, for their opinions. Once thesehad been received, a file consisting of theoriginal field notes, the opinions of WRPBand JW, as well as supplementary notes onthe birds I had seen around Madeira, wassent to Ken Preston, Secretary of the IrishRare Birds Committee (IRBC), for assess-ment.

ASSESSMENTThe record was assessed by the IRBC, andwas published in the 1975 issue of IrishBirds as ‘Pterodroma sp. 1974 record. One,not positively identified, but probably aSoft-plumaged Petrel, P. mollis off CapeClear, Cork on 5 September. This is the first

Southern COMPLETE INCOMPLETE

populations NUMBER BAND BAND

Marion 3* 3 0Kerguelen 1 0 1Falkland 1 0 1West Australia 1 0 1‘South Atlantic’ 1 0 1South Seas 1 0 1Inaccessible 2 1 1Nightingale 2 2 0Tristan da Cunha 4 4** 0Gough 5 4*** 1

Northern populations

Madeira 2 0 2Desertas 3 0 3

TOTALS 26 14 12

Table 1. Breast-band variability of specimens of ‘Soft-plumaged Petrel Pterodroma mollis’ at NaturalHistory Museum,Tring.* One dark morph** Two with complete band narrower and paler in centre*** Two with complete band narrower and paler in centre



record of the genus.’ Sharrock & Sharrock(1976) quoted the record as of a ‘Soft-plumaged Petrel’, with the proviso that ‘itis still under review for admission to theBritish and Irish list’.

POST-ASSESSMENTDEVELOPMENTSEven in the late 1970s, ‘Soft-plumagedPetrel’ was illustrated with a completebreast band (Heinzel et al. 1977; Tuck &Heinzel 1978). Furthermore, BWP (vol. 1)mentions a ‘grey band across the breast’ nofewer than three times before stating (forsubspecies feae) ‘sides of chest pale grey,sometimes forming interrupted bandacross’, although the plate (16) shows nobreast band; BWP goes on to say that ‘P. m.madeira is more heavily mottled on flanksthan feae’ (see below). Clearly, these birdswere little known and inaccuratelydescribed at that time.

In 1979 and 1986, I was able to return tothe Madeiran archipelago to surveybreeding seabirds, including the popula-tion of P. m. feae on the Desertas. As well asreceiving detailed help and advice fromAlec Zino, I was privileged to examine hisnumerous photographs of both P. m.madeira and P. m. feae taken within the arch-

ipelago. Through Gerry Maul, I also hadthe opportunity to examine the FunchalMuseum’s collection of both subspecies.None of the specimens showed a completebreast band (see fig. 2; and cf. photographsof P. m. mollis from the National Museumof Scotland, reproduced in Birding World 7:71).

Some progress was made in 1983, withtwo notable publications. Harrison (1983)at last drew a distinction between the fieldappearance of the ‘northern’ and‘southern’ populations, stating that thebreast band was variable, but was lackingon the ‘northern’ subspecies. Bourne (1983)proposed treating ‘Soft-plumaged Petrel’as three distinct species, Soft-plumaged P.mollis, Gon-gon P. feae and Freira P. madeira,mainly as a result of diminishing NorthAtlantic populations. He also mentionedthat ‘while northern populations of theSoft-plumaged Petrels are normally palewith white breasts, and the southern onesdarker with a band across the breast, occa-sional individuals in all populations aredarker with more marking below, or evendark all over in the southern populations.’He added: ‘Thus, the small form madeiralacks much mottling and appears to breedin the early summer in the mountains of

Figure 2. Specimens of Madeira Petrel Pterodroma madeira and Cape Verde Petrel P. feae from theFunchal Museum, showing absence of breast-band.



that island; and the large form feae, whichtends to be streaked on the flanks, breedsin the autumn on the offshore islands ofMadeira and in winter in the mountains ofthe Cape Verde Islands.’

Between 1982 and 1986, I gained consid-erable comparable experience of, and wasable to photograph, southern populations(P. m. mollis and P. m. dubia) at sea and onthe various breeding grounds in the SouthAtlantic and Indian Oceans.

In 1986, Zino & Zino published a paperwith photographs of all three species. Theystated: ‘The sides of the breast have avarying amount of light grey, but in noneof the live birds we have handled or in anyof the museum specimens we have exam-ined, have we found anything remotelyapproaching a complete breast band, suchas is present on most P. mollis from NewZealand.’ They added, however, that‘despite the considerable difference in sizebetween the Bugio and Madeira birds, wehave found it impossible to distinguish onefrom the other at sea.’

This was about the extent of publishedfield knowledge concerning the ‘Soft-plumaged Petrel group’ in 1989, whenseawatchers from headlands aroundBritain and Ireland started reporting singlebirds, generally in autumn. Similarly, onthe American side of the Atlantic, singleindividuals began to be seen on pelagictrips.

I am a founder member of the BBRC’sSeabirds Advisory Panel, and I was alsoconsulted by the IRBC on the growingnumber of sightings of ‘Soft-plumagedPetrels’ around Ireland. Finally, in 1995, Ilearnt informally from members of theIRBC that, after half my lifetime, the 1974Irish Pterodroma record was to be reviewed.

NORTH ATLANTIC HURRICANESAND PTERODROMA PETRELSSeabirds are known to be displaced by hur-ricanes and cyclones (Elkins 1995),although the exact mechanisms involvedare, understandably, little known. In theAtlantic and eastern Pacific, tropical

cyclones are referred to as hurricanes (fromthe term used by a Central American tribe,the Tainos, who called them ‘Huracan—theGod of Evil’: Anthers 1982). For definitionsof tropical cyclones, depressions, stormsand hurricanes, see Iacovelli (1997).Murphy (1936) provided a fascinatingaccount of birds and hurricanes, lookingspecifically at six hurricanes between 1876and 1933. Bourne (1967) discussed extremelong-distance vagrancy by petrels, mainlyin an historical context pertaining tovarious European lists; consequently, notall of the examples he cited are necessarily‘weather-related’, and undoubtedly some

Figure 3. Photograph of a depression to thesouthwest of the British Isles taken by the ESSA2 satellite at 10:18 GMT on 12th November 1966.The depression began as hurricane ‘Lois’ in theeastern Caribbean and moved northeastwardsuntil its winds fell below gale force on 10thNovember. Thereafter it began to deepen again,and the pressure at the centre had dropped to962 mb when this photograph was taken. Thefrontal zones are well developed, although the1000–500-mb wind shear was unusually weak forsuch a well-defined system. (Courtesy WeatherXXIV (6): 1969: 222) (Crown CopyrightReserved)



seabirds just become ‘lost’. Elkins & Yésou(1998) mentioned birds travelling in theeye of extra-tropical depressions, as well asbeing caught up in cyclic winds, especiallywhen these systems reach land. Interest-ingly, some of these weather systemsstarted out as hurricanes (‘Floyd’ in 1993;‘Iris’ in 1995) on the American side of theAtlantic.

In the Atlantic Ocean, tropical cyclonesoriginate in the central Atlantic generallybetween 10°N and 20°N, either from theCape Verdes or nearer the Caribbean (nearthe Lesser Antilles), within the Intertrop-ical Convergence Zone. Here, northeastand southeast trade winds converge toform a counter-clockwise rotation in theNorthern Hemisphere. These two discreteregions have the warmest seawater (27°C+)and the highest humidity, both prerequi-sites for cyclone formation (Barry &Chorley 1968). Although the ‘hurricaneseason’ is from June to November, mosthurricanes originate in August and Sep-tember and travel clockwise around theSargasso/North Atlantic subtropical high-pressure zone. Sometimes (but not always),they dissipate along the eastern seaboardof the USA when they meet land, onlyoccasionally tracking on into Canada.Alternatively, some systems track backclockwise over the North Atlantic, skirtingthe New England maritime states andCanada; these become downgraded toextra-tropical depressions as they losewarm, moist tropical air and enter thewesterlies above the North Atlantic ‘High’.Those that continue northeast across theNorth Atlantic often deepen again in midAtlantic before approaching Europe (Barry& Chorley 1968; Anthers 1982) (see fig. 3,on page 511).

Mature tropical cyclones are generallysmaller than extra-tropical cyclones,having a typical diameter of some 700 km,while the eye may be 16-50 km across. Theeye is crucial to both the generation ofextremely low pressures (generally 950 mb;lowest recorded 870 mb) and the develop-ment of intense wind speeds (maximum

recorded 88 m per sec, or 317 km per hour),although 90% of tropical disturbances failto form an eye (Anthers 1982). Once an eyeis formed, intensification of the system pro-ceeds rapidly. In the eye centre, air may bevirtually calm (or variable) and cloudcover may be broken, with adiabaticwarming of descending air, whereas thestrongest winds and heaviest precipitationare at the eye wall. Presumably, this is themechanism which both entraps and dis-places seabirds as the system moves slowlyacross the ocean at speeds of 16-24 km perhour.

In the course of the hurricane season,there may be as many as 100 tropical dis-turbances between 10°N and 20°N, withmore than half of them originating over theCape Verdes. In an ‘average’ season,however, only about ten of these will growto become a named tropical storm, aboutsix of which will intensify further to obtainhurricane status (verified by meteorolog-ical satellite and/or observations fromaircraft and ships).

The year 1974 was below average fortropical cyclones, with a total of sevenbeing named storms, four of which werehurricanes. The first of these was Hurri-cane ‘Becky’ (26th August to 2ndSeptember), which was never a threat toland, but was of concern to shipping as ittravelled most of the way across the NorthAtlantic. ‘Becky’ formed several hundredkilometres north of Puerto Rico on 26thAugust and attained tropical-storm statuswest of Bermuda on the morning of 28thAugust, reaching hurricane strength in thatafternoon. This was confirmed by a US AirForce reconnaissance aircraft (32.7°N68.6°W, about 360 km west of Bermuda). Atthis time, its movement was NNE at 10knots, with maximum sustained winds of65 knots and gusts to 80 knots. The area ofgale-force winds was enclosed in a semi-circle of radius 120 km to the east and 80km to the west, with seas reaching 4.5 m orhigher. The movement and developmentare shown in table 2 and fig. 4.

‘Becky’ continued to intensify over the



next two days as it moved slowly northeastover the open ocean. Maximum strengthwas observed on 31st August, with aminimum central pressure of 977 mb andsustained winds of 100 knots (22.00 GMT).On 2nd September, the system lost its trop-ical characteristics as it acceleratedeastwards, merging with a frontal zonenortheast of the Azores. By this stageknown as ‘Low B’ on the Bracknell weathermaps, it continued eastwards, with its lastplotted position, at 06.00 on 4th September,about 44°N 20°W, some 960 km southwestof Ireland.

While there is no proven link betweenHurricane ‘Becky’ and the Irish Pterodroma,the information from the MeteorologicalOffice, Bracknell, Berkshire, combined withthat from the Mariners Weather Log (1975,

vol. 19, No. 1), is presented here as a pos-sible mechanism by which seabirdsbecome transported across the open ocean.

Recent dedicated pelagic birding offNorth Carolina has shown that variousPterodroma species are offshore in the GulfStream at certain times of the year(Brinkley & Patteson 1998). Indeed, CapeVerde Petrel is proving to be a regularvisitor to deep waters off North Carolina,especially in May, with fewer in thesummer months. Occasionally, species ofPterodroma are cast nearer the shore orinland, especially in August and Sep-tember, at the peak of the hurricane season.

It may thus be only a question of timebefore such a pressure system, movingback into the North Atlantic, displacesthese and/or other seabirds to the Euro-

pean side of theAtlantic. In fact,this may havealready hap-pened: CappedPetrel hasoccurred inEngland, in1850, withanother beachcorpse found inYorkshire in1984. Muchmore exciting isa record of alive CappedPetrel watchedfor four hourson 26th Feb-ruary 1980 at

DATE & TIME POSITION MOVEMENT MAX. SUSTAINED WINDS

28.8.74 16.00 GMT 33.2°N 68.1°W NNE, 10 knots 65 knots (gusts to 80)29.8.74 16.00 GMT 36.8°N 64.3°W NE, 12 knots 85 knots (gusts to 115)30.8.74 16.00 GMT 38.2°N 60.0°W ENE, 12 knots 80 knots (gusts to 100)31.8.74 16.00 GMT 40.0°N 55.0°W ENE, 12 knots Est. 115 mph (satellite obs.)1.9.74 16.00 GMT 42.5°N 45.5°W E, 20 knots 100 knots (gusts to 130)2.9.74 16.00 GMT 43.0°N 35.0°W E, 15 knots 45 knots3.9.74 12.00 GMT c.44°N c.27°W East Now ‘Low B’4.9.74 06.00 GMT c.44°N c.20°W East

(960 km SW of Ireland)

Table 2. The development of Hurricane ‘Becky’ (see also fig. 4).

Figure 4. Path of Hurricane ‘Becky’, 28th August to 4th September 1974.



56°55N 15°07W, some 80 km southwest ofRockall and 480 km west of Scotland (Dan-nenberg 1983). This is by far the mostnortherly record of Capped Petrel in theNorth Atlantic, and Bourne (1986) has sug-gested that similar areas of productiveupwelling may support ‘Soft-plumaged’and/or Bulwer’s Petrels, especially in latesummer. Interestingly, Paul Buckley (inlitt.) has also suggested that the NewEngland Seamounts (between Bermudaand Newfoundland), apparently ornitho-logically unknown, may provideproductive upwelling for Bermuda PetrelP. cahow, Capped Petrel and other warm-water tubenoses, especially as they bisectthe main axis of the Gulf Stream.

Following the first records of ‘Soft-plumaged Petrels’ in the temperate NorthAtlantic, in 1974 (Ireland) and 1981 (two,North Carolina), small numbers have beensighted annually since 1989 (excluding1992) around Britain and Ireland and since1991 (except 1993) off the eastern seaboardof the United States, with a first Canadiansighting in 1997, off Nova Scotia on 7thJuly. These remarkable series of sightingssince 1989 pose several questions:

1. Why have these birds not been detectedbefore?2. Which species of the ‘Soft-plumagedPetrel group’ are now occurring regularlyin small numbers on both sides of theAtlantic?3. Are the North American and Europeansightings of the same or different individ-uals, and, if the same, could this representa regular clockwise migration around theNorth Atlantic?4. Why are North American observationsalmost exclusively from pelagic trips, withnone seen from land, whereas Europeanobservations are mostly from land, withalmost none reported at sea?

Tables 3 and 4 list those sightings of‘Soft-plumaged Petrels’ which I have beenable to trace from the literature for bothsides of the North Atlantic. While I suspect

YEAR DATE LOCATION

1974 5 Sep Cape Clear Island, Co. Cork, Ireland

1989 12, 13, 14 Aug Porthgwarra, Cornwall1989 14 Aug Old Head of Kinsale,

Co. Cork, Ireland1990 26 Aug Cape Clear Island1991 20 Aug St John’s Point, Co.

Down, Ireland1991 6 Sep Flamborough,

North Yorkshire1991 6 Sep Flamborough1992 24 Oct Camperduin,

Netherlands1993 11 Aug Cape Clear Island1993 25 Aug Oostende, Belgium1993 5 Sep Farne Islands,

Northumberland1993 5 Sep Hauxley,

Northumberland1994 24 Aug Mizen Head, Co. Cork1994 24 Aug Mizen Head1994 10 Sep Bardsey, Gwynedd,

Wales1995 27 Jul Cape Clear Island1995 27 Jul Cape Clear Island1995 25 Aug Bridges of Ross,

Co. Clare, Ireland1995 26 Aug Brandon Point,

Co. Kerry, Ireland1995 26 Aug Kerry Head, Co. Kerry1995 8 Sep Merseyside1995 8 Oct Cape Clear Island1996 11 Jun Porthgwarra1996 25 Jun 80 miles WNW of

Shetland, Scotland1996 18 Aug 2.5 miles W of Bishop

Rock, Scilly1996 22 Aug St John’s Point1996 22 Aug Cape Clear Island1996 24 Aug Pendeen, Cornwall1996 13 Sep Cley, Norfolk1996 13 Sep Newbiggin,

Northumberland1996 14 Sep Hauxley1996 20 Sep Farne Islands1996 4 Oct Strumble Head,

Pembrokeshire1997 26 Jun Presumed same bird

Cley, Blakeney,Sheringham & Mundsley, Norfolk

1997 31 Jul Bridges of Ross1997 24 Aug Cape Clear Island1997 12 Oct Portland Bill, Dorset1997 12 Oct Cley1998 20 Aug Bridges of Ross1998 24 Aug Newbiggin1998 8 Sep Cape Clear Island

Table 3. European sightings of ‘Soft-plumagedPetrels’ Pterodroma mollis/madeira/feae, 1974-98.All, with the possible exception of the August1989 observations at Porthgwarra, involved singlebirds.



reveals a summer distribution from May toNovember, with no sightings duringDecember-April. Two definable peaks areevident, one in May and the other inAugust-September, and this becomes moreinteresting when one looks at the geo-graphical patterns. Figs. 6 & 7 show themonthly distribution of sightings in,respectively, the northeast (‘European’) andthe northwest (‘North American’) Atlantic:North American sightings reveal a markedpeak in May, which decreases through thesummer months until November, whereas,in Europe, there are no reports at all inMay, but a distinct peak in August andSeptember. While both data sets appearnon-random, interpretations andhypotheses are not easy to correlate witheach other.

To date, the only ‘Soft-plumaged Petrel’found inland, and directly attributable to ahurricane, was one at the John Kerr Reser-voir on the state border of North Carolinaand Virginia, some 200 km inland, on 5thor 6th September 1996, after the passageinland of Hurricane ‘Fran’. Given the sus-ceptibility of seabirds to hurricanestracking inland off the eastern UnitedStates, especially in late summer, it is sur-prising that this is the only inland record,although ‘Soft-plumaged Petrels’ may notbe that numerous in those waters duringthe hurricane season.

In addition, some of the Europeanobservations have been made in fineweather conditions, rather than before orafter deep depressions. Thus, while themechanism exists in late summer (hurri-canes in the USA; downgraded hurricanesand deepening depressions in Europe)potentially to aid any clockwise migration,there appears to be insufficient evidence atpresent to link this with (at least) the north-east Atlantic sightings. This seems tosuggest a regular, non-random pattern ofdispersal on both sides of the Atlantic.

CONCLUDING THOUGHTSNot surprisingly, there has been a subse-quent proliferation of papers and notes

that neither list is complete, and I do notknow which of the reports have been for-mally accepted, there now appear to beover 60 reports of ‘Soft-plumaged Petrels’in the temperate North Atlantic. Fig. 5

YEAR DATE LOCATION

1981 24 May 40 miles SE of Hatteras Inlet, North Carolina

1981 3 Jun 35 miles ESE of Cape Hatteras Point

1984 9 Nov 90 miles E of St Catherine’s Island, Georgia

1991 25 May 52 miles SE of Oregon Inlet, North Carolina

1992 24 May 35 miles SE of Hatteras Inlet

1992 31 May 40 miles SE of Oregon Inlet

1992 27 Jun 57 miles SE of Oregon Inlet






1995 30 Jul 54 miles SE of Oregon Inlet

1995 9 Sep 55 miles E of Back Bay, Virginia

1995 16 Sep 30 miles SE of Hatteras Inlet



1996 20 Jul 25 miles ENE of Hatteras Inlet

1996 10 Aug 50 miles SE of Oregon Inlet

1996 6 Sep 200 miles inland: John Kerr Reservoir, NorthCarolina/Virginia

1997 7 Jul Sable Island, Nova Scotia, Canada

1997 28 Jul Oregon Inlet1998 29 May Off North Carolina1998 31 May Off North Carolina

Table 4. North American sightings of ‘Soft-plumaged Petrels’ Pterodroma mollis/madeira/feae,1981-98. All records involve singles. 1 nauticalmile = 1.852 km.



from both sides of the Atlantic on ‘Soft-plumaged Petrel’ distribution andidentification, some of which are moreaccurate than others. These are listed in thereferences. Bretagnolle (1995) has recentlysuggested uniting all Atlantic populationsinto one species, but Knox (1995) and Tove(1997) have questioned this, and the tax-onomy of these petrels is far from resolvedat present. It would seem that the northeastAtlantic birds are probably as closely

related to the Caribbean Ptero-droma species as they are to‘southern’ Soft-plumagedPetrels.

After consideration, Tove(1997) gave very sound reasonsfor dismissing the possibilitythat North American recordsinvolved individuals from eitherMadeira or the South Atlantic.Although Jepsen & Zonfrillo(1986) tentatively identified twopetrels on 9th September 1986between Deserta Grande andMadeira as southern P. mollis,this appears unlikely, and thereis very little evidence forsouthern P. mollis moving northinto the temperate NorthAtlantic.

The critically low populationof the Madeira Petrel makes itvirtually certain that NorthAmerican records are not of thisspecies. The same probablyapplies also to an evolutionarilyimportant, but probably verysmall population recently foundon the Azores (Bibby & del Nevo1991; Monteiro & Furness 1995),but predicted three decadesearlier by Bourne (1965). Fur-thermore, it is not known ifeither of these populations ismigratory; it is possible thatMadeira Petrels may remainaround Madeira when notbreeding, although they are

known not to be on the breeding ledges inJanuary.

Tove (1997) speculated that the petrelsseen off North America are Cape VerdePetrels, and probably from the Bugio(Desertas) population rather than the CapeVerdes themselves. He based this on thetiming of the breeding season(July/August to January/February onBugio, but September/October toApril/May in the Cape Verdes), as well asthe absence of barring on the flanks of

Figure 5. Monthly distribution of temperate North Atlanticsightings of ‘Soft-plumaged Petrels’ Pterodroma mollis/madeira/feae.

Figure 6. Monthly distribution of European sightings of ‘Soft-plumaged Petrels’ Pterodroma mollis/madeira/feae.

Figure 7. Monthly distribution of North American sightings of‘Soft-plumaged Petrels’ Pterodroma mollis/madeira/feae.



those individuals observed more closelyand photographed. While this interpreta-tion may or may not be correct, it seemsunlikely that ‘European’ records, with theirpeak in August and September, refer to theBugio population, as the latter is thenbreeding (Bourne 1983; Collar & Stuart1985; Jouanin et al. 1969; Zino & Zino 1986;pers. obs.). In fact, the distribution of Euro-pean records would probably tend tofavour the Cape Verdes as a source. More-over, the Cape Verdes population is largerthan that on Bugio, although accurate, up-to-date figures are difficult to obtain.

Perhaps Bugio breeders are offshore inAmerica from May onwards, whereasthose from the Cape Verdes are offshore inEurope in August and September? Alterna-tively, petrels from the Cape Verdes, afterbreeding, may disperse rapidly (from Mayonwards) to the east coast of the USA, andthen possibly move onwards on a clock-wise route to Europe.

ACKNOWLEDGMENTSI acknowledge the help and advice pro-vided by Geoff Brundrit (Professor ofOceanography, University of Cape Town),who not only commented on the originaldraft typescript and enabled me to use theOceanography Library at UCT, but alsodirected me to the CSIR Library at Stellen-bosch for oceanographic referencespertaining to 1974 and 1975 (the onlycopies in South Africa).

In addition, I thank Paul Buckley (Pro-fessor of Oceanography, University ofRhode Island) for comments and for clarifi-cation regarding the New EnglandSeamounts.

Dick Newell and Tony Marr answeredparticular queries, as did the National Hur-ricane Centre (Miami, Florida). I thank CazThomas for typing, graphics and criticalcomment, as well as for revising the manu-script in my absence before publication. Ialso thank Dr Tim Sharrock for the oppor-tunity at last to write up this long-outstanding record.

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AUTHORJ. W. Enticott, 12a Rose Avenue, Kirstenhof7945, South Africae-mail: [email protected]

EDITORIAL COMMENTOn behalf of the Irish Rare Birds Com-mittee, Paul Milne has commented: ‘Thereis a rich history behind this record andother “Soft-plumaged Petrel” records offIreland and the full analysis of the IRBC’sdecisions would require comprehensivetreatment, which may be carried out at alater date.

‘This particular record was first pub-lished in the 1975 Irish Bird Report (23: 6).The IRBC “upgraded” the record toFea’s/Madeiran Soft-plumaged Petrel in1997 (Irish Birds 6: 65), after reviewing thisand all subsequent records and judging

that they belong to one of the two NorthAtlantic species. As we stated there, “it isparticularly gratifying to now be able torecognise the first record for Europe (1974),previously accepted as an unidentifiedPteradroma [sic] sp., which preceeded [sic]the first of the recent spate of records byfifteen years.”

‘We also draw your attention to the 1996IRBC Report (Irish Birds 5: 478), where weexplained the reasoning behind our use ofthe English names Fea’s Soft-plumagedPetrel for P. feae, Madeiran Soft-plumagedPetrel for P. madeira and Southern Soft-plumaged Petrel for P. mollis.’

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