scillypelagics

ABSTRACT A Fea’s Petrel Pterodroma feae was seen from a boat approximately 10 km south of Scilly on 8th July 2001. Although there had been several previous sightings of Fea’s/Zino’s Petrels P. madeira in British waters, this sighting constitutes the first unequivocal record of Fea’s Petrel for Britain. The total duration of the event lasted about 12 minutes, during which time the Fea’s Petrel flew past the boat on four or five occasions at a distance of no more than 20 m. Close views enabled detailed scrutiny of many key structural and plumage features, and this was supported by a high-quality video sequence. The elimination of Soft-plumaged Petrel P. mollis and Zino’s Petrel is discussed.

The one thing certain about pelagic trips is that you can never be certain what you will see. The 2000 pelagic season off Scilly had been particularly good, and July was by far the best month. In contrast, the 2001 season had been fairly quiet, the highlights being single Wilson’s Storm-petrels Oceanites oceanicus on eight dates up to 8th July, and we had become despondent. Our efforts were, however, more than compensated for on 8th July when, out of the blue and quite astonishingly, a Fea’s Petrel Pterodroma feae appeared at point-blank range off the starboard side of M. V. Kingfisher.

On the evening of 8th July 2001, we were drifting and chumming approximately 10 km south of Scilly at 49°48.573’N, 06°11.370’E. Weather conditions were fair. The wind was a moderate (force 3) northwesterly, enough to disperse the smell of the chum and cause drift, but the sea state remained reasonably calm with a slight swell and light waves. Cloud cover was 100%, but thin and high. All in all, conditions were good for a pelagic trip. Bob Flood (RLF) was in the cabin scanning the slick on the port side and Ashley Fisher (EAF) was on deck covering the same area. Nigel Wheatley, along with three visiting birders including Pete Massey (PM) and Mark Ponsford (MP), were watching the starboard side. It had been another quiet evening when, cutting into the silence, we both heard Nigel Wheatley’s distinctive yet perplexed voice from the starboard side asking, ‘What’s that?’ Given the onset of apathy, this vague and restrained question barely attracted our interest. A few moments later, now flavoured with a touch of panic, Nigel exclaimed, ‘What the **** that?!’ EAF instantly pivoted through 180° and almost immediately screamed, ‘It’s a Fea’s! It’s a Fea’s! It’s a **** Fea’s!’ In a flash, RLF leapt out of the cabin and without hesitation agreed with EAF.

The bird had approached the bow of the boat from the east and passed the starboard side at a distance of about 10 m, continuing around the stern, roughly to the southwest. During this quick view, we established that the flight action was distinctive and, in general, appeared pratincole Glareola -like, buoyant with quick wing beats and circling glides (cf. Gantlett 1995). It maintained this pattern of flight as it meandered some way off to the southwest. Nobody expected that this dream bird would turn back on itself and pass the boat again; but it did, four or five times, and each time at no more than 20 m. At each pass we were able to pay particular attention to the crucial features which separate Fea’s Petrel from the closely similar Zino’s Petrel P. madeira, including plumage detail, bill and wing structure, and the bulk of the head, neck and body.

It was immediately apparent to all observers on M. V. Kingfisher that our bird had a stockier body and much longer wings than Manx Shearwater Puffinus puffinus (also seen that evening). A striking feature was its deep and heavy black bill. The head was thickset, with a dark crown and ‘panda-like’ smudge marking through the eye. There were smudge markings at the side of the neck, but these did not continue across the breast in a full or even partial band, so the centre of the breast remained completely white. The body was substantial with a full breast, tapering at the rear to a blunt point at the end of the tail. The underparts (including the breast) were bright white, while the mantle was grey. The wings had both a long ‘hand’ and ‘arm’, and the trailing edge of the primaries showed little or no convex curvature and was clearly pointed. A subtle ‘M’ was visible across the brown-grey upperwings, while the underwing showed a pattern of greys with a small extension of white onto the base of the under-forewing. Video footage was secured and video-grabs illustrate many of the features described above.

The experience was breathtaking, not only because of the close views, but also because the bird stayed with the boat for so long and swept past at close range on four or five occasions. It was able to glide seemingly without effort low over the sea on bowed wings and yet, in a moment, was able to carry out graceful sweeping turns and circular manoeuvres. It is not possible to describe in words the impact of such a sight on a seabird fan! The Pterodroma petrels are near-mythical birds, and to see a Fea’s Petrel so well and within sight of home was nothing short of awe-inspiring.

In comparison with Manx Shearwater seen that evening: (a) body length roughly the same; (b) head and neck more thickset and body form stockier; (c) wings noticeably longer; and (d) bill a good deal heavier and deeper.

Bill: large, heavy, and deep. Head and neck: large bull-head and thick neck. Body: stocky and full-chested, tapering towards rear end. Tail: long and tapered, coming to a blunt point. Wings: long, slim wings with pointed hand, and minimal convex curvature to the trailing edge of the primaries (apparent in every frame of the video footage).

At distance, the bird was almost monochrome. Head: ostensibly hooded, comprising a dark, dirty grey crown, darker than neck and mantle, and darker again panda-like smudgy blackish eye-patch. Mantle: grey, contrasting with paler uppertail-coverts and tail. Tail and uppertail-coverts: paler than the rest of the upperparts, appearing pale grey to almost white. Throat and underparts: white. Central breast: clear and unmarked with no more than a grey patch on the sides of the neck and upper-breast, and thus lacking a lateral breast-band. Upperwing: grey-brown (more brown than grey) with an observable but, to some observers, subtle ‘M’ across the outstretched wings formed by dark primaries and primary coverts, dark secondary, median and lesser coverts, and a dark band across an otherwise grey rump that connected the two ‘half-Ms’ on each wing. Underwing: at long-range, appeared entirely dark. At middle-range, a small extension of white onto the base of the under-forewing was apparent and, at close-range and also visible in video-grabs, a complex of grey shades that formed a broad, dark bar in the region of the median underwing-coverts, and which faded at the carpal joint. This dark bar was accentuated by the conspicuous white inner forewing and a greyer central area extending to the arm and hand. Trailing edge appeared darker than the greyer central area.

Distinctive and typically that of a Pterodroma. The following describes the Fea’s flight action as caught on video. At times gliding quite effortlessly, low over the sea on bowed wings, punctuated occasionally by two to six wingbeats. The bird would gain momentum with a run of faster wingbeats, and rise effortlessly up to 3–4 metres, turn and complete a full circle on a downward glide before tilting the other way and peeling off in the opposite direction.

Watch the original video footage of the first confirmed sighting in British waters: please be advised this video contains strong language Click here

Separation of Fea’s and Zino’s Petrels requires the utmost care and attention to detail, combined with exceptional viewing conditions, while the unlikely possibility of a Soft-plumaged Petrel P. mollis is more readily addressed. Until the appearance of the Scilly bird, no Fea’s/Zino’s Petrels seen previously around the coasts of Britain had been sufficiently close, or lingered for long enough, to enable the crucial features to be examined in detail. Now, we were presented with an unprecedented opportunity to clinch the identification to the species level, one way or the other. Although we had no prior experience of positively identified Fea’s or Zino’s Petrel, RLF had previously seen two Fea’s/Zino’s Petrels from Scilly-based pelagics and Soft-plumaged Petrel at sea off Cape Town, South Africa. Subsequently, he has seen Fea’s Petrel near Madeira, another positively identified Fea’s Petrel off Scilly, and a further three Fea’s/Zino’s, also off Scilly. In addition, PM and MP had seen one Fea’s/Zino’s Petrel while seawatching from the mainland, but for EAF, this was his first ever Pterodroma, although he has since seen another positively identified Fea’s Petrel and two additional Fea’s/Zino’s Petrel from Scilly-based pelagics. Added to this, both RLF and EAF are highly experienced pelagic seabirders, typically venturing into the seas around Scilly about 50 times each year between June and October in search of seabirds, in most sea states from balmy doldrum conditions up to force 6 or 7. Thus, we are extremely familiar with all the likely species that we could encounter, in a range of weather and sea conditions. Consequently, we were fully aware of all the features that we needed to concentrate on in the event of such an encounter.

Given the outstanding views and supporting video footage of this bird, we knew the possibility existed that this bird could be positively identified. Excluding Soft-plumaged Petrel was fairly straightforward at the time of observation, owing to the lack of breast-band and whitish tail among other things, but eliminating the closely similar Zino’s Petrel required careful attention to detail and critical observation of key features. After 12 minutes of terrific views, combined with photographic support, we were confident that we had also eliminated Zino’s Petrel.

Soft-plumaged invariably has a complete, or near complete, lateral breast-band (of 250 seen in the southern oceans in March 2006, RLF noted just one with a near complete lateral breast-band, the remainder being complete), whereas our bird showed a clear and unmarked breast with no more than a grey patch on either side of the neck and upper breast. Our bird also had a dark, dirty-grey crown, darker than the neck and mantle, whereas a Soft-plumaged Petrel would show a ‘clean’ grey crown, similar in tone to neck and mantle. In addition, the tail of the Scilly bird was paler than the rest of the upperparts, appearing somewhere from pale grey to almost white, whereas the tail of Soft-plumaged is clean grey and similar in tone to the mantle. Crucially, the bill structure of our bird was large, heavy and deep, whereas the bill structure of most Soft-plumaged Petrels is intermediate between Fea’s and the much slimmer bill of Zino’s Petrels (see Ian Lewington’s illustrations in Harrop 2004). We were extremely confident that Soft-plumaged Petrel had been eliminated using this combination of features.

Given that the plumages of Fea’s and Zino’s Petrels are, to all intents and purposes, identical, their separation relies on a combination of size and structural differences, with Fea’s being the larger and heavier of the two species.

The body size and structure of our bird, in comparison with Manx Shearwater, was about the same length, but stockier, which favours Fea’s Petrel. Furthermore, the body was stocky and full-chested, tapering towards the rear end; the bird was bull-headed and thick-necked, features which again point towards Fea’s, and which are supported by the video sequences. In comparison, Zino’s Petrel is said to be decidedly smaller than Manx Shearwater in body size, with a fairly slender and near flat-chested structure, thus tapering to a long narrow rear end, and with the head and neck described as dove-like, not hefty, and more like a Cookilaria petrel (Brinkley 2004). The above three points are strongly indicative of Fea’s Petrel, and given that it is, on average, approximately 50% heavier than Zino’s, this difference must be evident in the field.

Bill structure is undoubtedly the single most crucial feature which can clinch the identification. The bill of our bird was large, heavy and deep; a feature noted at the time of observation and again supported in the video sequences. In comparison, the bill of Zino’s is described as shallow, even thin, in profile. Reports from observers who have been fortunate to observe Zino’s Petrels at sea confirm that the light bill structure gives Zino’s a very distinctive look, and quite different to Fea’s (Brinkley 2004; also see photograph in Fisher 1989).

Wing shape provides further supporting evidence towards a positive identification in favour of Fea’s Petrel. In all still images taken from the video footage, and thus as seen in many different positions, the wing-shape of our bird is long and slim, with pointed ‘hands’ and minimal convex curvature to the trailing edge of the primaries. In general, the wing of Fea’s Petrel appears long and slim because P10 is longer than P9 (primaries numbered descendantly, P10 being the outermost). In contrast, the wing structure of Zino’s Petrel appears shorter and blunter because P10 is the same length as, or slightly shorter than, P9. This issue is important, as it explains the difference between the ‘pointed Fea’s vs. blunter Zino’s wing tip theory’ (Gantlett 1995; Tove 2001).

Including the July 2001 bird described above, we are fortunate to have observed six Pterodroma petrels on pelagic trips off Scilly. Although viewing conditions varied, all appeared identical in shape and structure, and there is no evidence to suggest that any of these six Pterodromas are anything other than Fea’s Petrel. One individual seen particularly well from M.V. Sapphire on 6th September 2004, approximately 17 km west of Scilly, for about ten minutes at close range, has also been accepted as a definite Fea’s Petrel (Flood & Lascelles 2004; Rogers 2005). On this individual, we were able to see an additional important feature that supported the identification as Fea’s Petrel (from photographs, although not visible in the field). The bill had a notch-like shape between the tip of the nostrils (naricorn) and the back of the hook at the tip of the upper mandible (maxillary unguis). In comparison, Zino’s has a wedge-like shape rather than a notch-like shape (Harrop 2004).

Flood, R. L., & Lascelles, B. 2004. Another Fea’s Petrel off Scilly. Birding World 17: 392.

Gantlett, S. 1995. Field separation of Fea’s, Zino’s and Soft-plumaged Petrels. Birding World 8: 256–260.

Harrop, A. H. J. 2004. The ‘soft-plumaged petrel’ complex: a review of the literature on taxonomy, identification and distribution. Brit. Birds 97: 6–15.

Rogers, M. J. and the Rarities Committee. 2005. Report on rare birds in Great Britain in 2004. Brit. Birds 98: 628–694.

Tove, M. 2001. Verification of suspected field identification differences in Fea’s and Zino’s Petrels. Birding World 14: 283–289.

Ashley Fisher & Bob Flood