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IDENTIFICATION ARTICLES

A record of Kermadec Petrel (Pteredroma neglecta) on Kaua'i, Hawai'i during the summers of 1998, 1999 and 2000.

On the evening of 11th July 1998 I was birdwatching at Kilauea Point National Wildlife Refuge, awaiting the regular evening flyover of Hawaiian Petrels (Pterodroma sandwichensis). I had observed three Petrels flying in over the Point and head inland towards the Mokolea Mountains, when I noticed a large, dark bird fly in from the sea from the North East at about 1940 hrs. The bird made numerous "passes" over Moku'ae'ae Islet, the small island located just offshore from Kilauea Point, before finally landing on the island. Unfortunately the light was fading quickly and therefore visibility was poor, however I did manage to note that the bird had pale patches on the upperside and underside of the wings at the base of the primaries and greater primary coverts. Once on the ground the bird was lost from view.

It was obvious that the bird was something unusual and I racked my brain trying to think of what the species was. From the plumage it seemed to fit well with the Catharacta Skua complex. However the size of the bird did not quite fit. I am very familiar with Great Skua (Catharacta skua) from birding in Europe and these are obviously larger and bulkier than the bird appeared to be, I also knew that it was more likely to be a South Polar Skua (Catharacta maccormicki) in the Pacific. It seemed plausible that if this was a vagrant South Polar Skua miles off course and roosting on an offshore island, then it might be a "runt" individual and therefore not be of the usual size. I checked through the available literature, which was unfortunately very scant, as most of my books were back in England, and thought it was best to release the news as a South Polar Skua. If it was one I knew that people would definitely want to see it and if it was not one then it must be something even better!

The bird continued to arrive at Kilauea Point in the late evenings but generally remained distant and so identification remained uncertain. By the 18th the bird had settled into a routine of flying over Mokuaeae Islet on first arrival and then proceeded to gain height and fly high over Crater Hill (East of the Refuge) and over the refuge entrance. I was joined by Reggie David and Tom Snetsinger on 22nd and through a process of elimination and much booksearching by ourselves and helpful comments on the birders hotline from many birders, it was decided that the bird was a dark-morph Kermadec Petrel (Pterodroma neglecta).

The bird was seen on and off throughout July, August and September of 1998, being last heard on the 21st September at 2200 hrs. I left Kaua'i to return to England on the 24th and so it is unknown if the bird was heard or seen after this date. When I returned to Kaua'i on October 30th I did not see the bird. It subsequently became apparent that what was presumably the same bird had been seen a couple of times in June 1998 by refuge biologist Adam Asquith, but had remained unidentified . During the last month and a half of its stay the bird often changed its behaviour and pattern of visiting the Point.

When the bird had first arrived it would always roost on Moku'ae'ae Islet and only flew high over the Refuge on stiff winged glides with hardly ever a wing beat, it later changed this behaviour to flying low over the point, with glides interspersed with deep flaps and hovering along the cliff faces, at levels of no more than a few feet at times. During late August it also created a "nest" scrape amongst the Shearwater colony and would roost here instead of on Moku'ae'ae Islet. In late August and September the bird was also seen and heard in the early mornings (between 0200hrs and 0700 hrs). During 1998 and occasionally during 1999 the Petrel would not be seen for several days at a time, sometimes for as long as a week, and this was presumably when the bird was out at sea feeding.

On May 9th 1999 whilst once again birding at Kilauea Point for the regular evening passage of seabirds I heard a familiar (and heartstopping) call coming from the Eastern side of the Point. I immediately recognised it as the call of the Kermadec Petrel and it was soon relocated gliding about the cliff face opposite the visitor centre. The bird again remained throughout the summer, usually roosting on the 1998 nest scrape, with the last sighting on August 23rd. Several visits to the Point in September failed to locate the bird.

In 2000 the bird again returned to Kilauea Point, on the 24th April and remained until September 11th, where it showed on most days and again took up residence amongst the Wedge-tailed Shearwaters (Puffinus pacificus), although on a different nest scrape than the previous year.

On one occasion the Petrel was seen chasing Wedge-tailed Shearwaters offshore, presumably using its Skua-like wing flashes to impersonate a Skua and force the Shearwaters to drop their food.

In 2002 an unidentified all-dark Petrel at Kilauea Point NWR, Kaua'i during May was probably the returning bird from 1998-2000, although the observers were unsure of the bird's exact identification, and no-one who had seen the Kermadec Petrel in 1998 - 2000 were present to compare the individuals or offer an identification.

Description

Size and structure

The Petrel was obviously large and quite bulky, and in comparison with Wedge-tailed Shearwater appeared fatter and broader winged. It also seemed to be closer in wing length to Wedge-tailed Shearwater than the literature suggests (Wingspan 36 inches for Kermadec Petrel, 38-41 inches in Wedge-tailed Shearwater), but this may have been due to the broader wing-tips in the Petrel giving the impression of a longer wing. The measurements for typical South Polar Skua are much larger (wingspan 50 inches). The bird often showed a barrel-chested appearance, particularly when flying slowly face on.

On land the bird was rather clumsy, and was seen on several occasions when on Moku'ae'ae to fall over vegetation when walking. When sitting on the ground and seen at close range the bird was compact and quite bull-necked with a steep forehead.

Plumage

In flight the bird could appear to be different shades of brown depending on the light. In strong sunshine the bird would often appear almost ginger in colour, whereas in duller conditions the bird could appear to be any colour between dark chocolate brown to light brown, often with a greyish cast to the plumage. When seen close on the land the plumage could be better seen and was generally dark brown overall with paler shades of brown on the head, face, and breast. At times a paler area could also be seen on the nape (seen both in flight and at rest), but this also appeared to depend on the angle of light. It was slightly paler below than above and on the wings. Bailey, Pyle and Spear (1989) state that fresh individuals of Pterodroma Petrels are paler and greyer and progressive wear makes the colour tones darker and browner, this would fit in well with the seemingly variable plumage of the Kilauea bird from month to month and year to year.

In flight the pale bases to the primaries and greater primary coverts were easily seen, often resembling a Skua, although this also changed with angle of light and whether the bird had its wing stretched or compacted. On the underside during 1998 the white bases often appeared as a double white patch, whereas this was not as noticeable during 1999, perhaps due to moult. In some lights the trailing edge of the wing also appeared as a paler strip.

Kermadec Petrel over Kilauea Point NWR, Kaua'i, May 2000. Left: underparts, right: upperparts. Note the white wing-flashes above and below, the paler rear to the wing on the left photo and the tail shape.

Photograph © by Christian Melgar

The tail was generally held closed during soaring flight, unless in windy conditions when it would often be fanned and used as a rudder. The shape and length of the tail could look remarkably different depending on how it was held, looking long and oval-ended in one instant, square in the next or short, wide and very rounded. The tail was the same colour as the upperbody and showed a neat row of white spots at the base. There were also very small pale tips to the tail feathers, but this feature was only noticeable in very good, well lit views from above.

Kermadec Petrel over Kilauea Point NWR, Kaua'i, May 2000. Note the chestnut-ginger plumage tones, white wing-flash and white spots at the base of the tail, which became more obvious when the tail was spread.

Photograph © by Christian Melgar

The bird was large-headed with a steep forehead, which was also obvious in flight. Overall the head was brown but the facial area was much paler, especially the lores, forehead and lower cheek area. There was a slight darker strip running from the eye to above the lores, but this was often difficult and sometimes impossible to see.

Bare parts

The bill was all-dark, very broad based, quite short and with a pronounced gonydeal angle and hooked tip. The gape was bright pink. The legs were dark grey to black and relatively short, making walking on land difficult (mostly short movements with a side to side waddling motion).

Close-up of Kermadec Petrel bill and head features, Kilauea Point NWR, Kaua'i, May 2000.

Photograph © by Christian Melgar

Discussion

Although the plumage and initial flight behaviour of the bird suggested a Skua species (especially when the bird was seen behaving as a Skua, chasing Shearwaters and Tropicbirds), it soon became apparent that the bird was in fact a Pterodroma species. The size, shape and all dark plumage left only a few candidates, however identification of Pterodroma Petrels is notoriously difficult, especially at sea. Luckily superb views (eventually) provided by the Kilauea bird allowed a 100% certain identification. The species which are most likely to cause confusion are dark morph Herald Petrel (P. arminjoniana),dark morph Murphy's Petrel (P.ultima), Solander's Petrel (P. solandri), Grey-faced Petrel (P. macroptera), Kerguelen Petrel (P. brevirostris) and dark morph Soft-plumaged Petrel (P. mollis) (Harrison 1983 and 1987).

Kermadec Petrel on "nest scrape", Kilauea Point NWR, Kaua'i, May 2000.

Photograph © by Christian Melgar

Dark morph Herald Petrel could be eliminated as this species does not show the white patches on the upperwing, although during moult white patches could be present and photographs of some individuals show what appears to be white or very pale primary shafts. Whether this is just due to the light angle or is a true representation of what the birds looked like should be taken into consideration if faced with a distant Petrel.

Murphy's Petrel differs in having all dark wings, often a dark "M" across the upperwing and at close range the throat is whiter than the forehead.

Solander's Petrel is larger (though size is often difficult to discern if no other birds are present), lacks the white patch on the upperwing, has a wedge-shaped tail and larger bill, when seen at close range. The species also tends to exhibit a hooded effect.

Grey-faced or Great-winged Petrel can be eliminated due to the lack of white patches on both the upperwing and underwing.

Kerguelen Petrel can also be eliminated by the lack of patches on the upperwing.

Lastly dark-morph Soft-plumaged Petrel can be ruled out by the lack of upperwing flash, less defined white patches on the underwing and flight jizz (Harrison 1985; Bailey et al. 1989).

Kermadec Petrel on "nest" scrape, Kilauea Point NWR, Kaua'i, May 2000.

Photograph © by Christian Melgar

Kermadec Petrel over Kilauea Point NWR, Kaua'i, May 2000. Note the deep-chested appearance.

Photograph © by Christian Melgar

Distribution and Occurrence

Kermadec Petrel breeds Lord Howe, Kermadec, Austral, Pitcairn and Easter groups (Harrison 1985) and egg dates are reported as October-February, fitting well with the arrival and departure dates of the Kilauea bird, although construction of a nest scrape, repeated calling and flight displays of this individual seem a little premature and optimistic! Lindsey (1986) states that on Kermadec Island there are two breeding "seasons" from August to May and December to August (also Harrison 1983, del Hoyo et al.1992).

Bailey et al. Deal with the dispersal of Pterodroma Petrels into the North Pacific off North America and note several records for the Hawaiian Islands (Kure Atoll, April 1923; at least six individuals along the 158 degree W meridian in November 1976 and a single bird in Northwestern Hawaiian waters on November 3rd 1984). Kermadec Petrels were reported as being "pretty widespread" and were being seen daily in small numbers in the autumn of 2002 in the far eastern part of the EEZ, but strictly >150nmi out (Michael Force, Brett Jarrett, Richard Rowlett). Light morph Kermadec Petrels were also seen on 18th and 20th September in the same area (Michael Force, Brett Jarrett, Richard Rowlett). In October 2002 the following were recorded from a research vessel: 1on 8th October, 190 NM NNE of Opana Point, Maui (Mike Force, Richard Rowlett); 3 on 9th October, 130 NM NE of Kahuku Point, O'ahu to 125 NM NE of Kilauea Point, Kaua'i (Mike Force, Richard Rowlett, Brett Jarrett). A total of 33 Kermadec Petrels were seen in Hawaiian waters by this research vessel team in the autumn (Mike Force, Richard Rowlett, Brett Jarrett). So it seems very likely that Kermadec Petrel is a regular visitor to waters around the central and Northern Pacific, but land-based records, particularly of live, good conditioned individuals are extremely rare.

Acknowledgements

My thanks goes to all those birders who came to see the Petrel at Kilauea and those who provided useful comments and references. Particular thanks go to Reggie David, Tom Snetsinger, Peter Donaldson and Robert Pyle who provided first hand help and those on the Hawai'i birders hotline who gave their help and advice, as well as a few slightly heated debates! Invaluable information was obtained from the Bailey, Pyle and Spear article on dark Pterodroma Petrels and anyone interested in this group of seabirds should become totally familiar with its contents.

References

BAILEY,S.F., PYLE,P. and SPEAR,L.B. 1989. Dark Pterodroma petrels in the North Pacific: identification, status, and North American occurrence. American Birds 43; 400-415.

DEL HOYO, J. et al. 1992. Handbook of the Birds of the World, Volume 1. Lynx edicions, Barcelona.

DUBOIS, P. and SEITRE, R. 1997. Herald Petrel: a new species for the Western Palearctic. Birding World 10:12; 456-459.

ENTICOTT, J. and TIPLING, D. 1997. Photographic Handbook of the seabirds of the World. London.

HARRISON, P. 1985. Seabirds: an identification guide. Second edition. Christopher Helm, London.

HARRISON, P. 1987. Seabirds of the World: a photographic guide. Christopher Helm, Kent, UK.

LINDSEY, T.R. 1986. The seabirds of Australia. Angus & Robertson, North Ryde, New south Wales.

PRATT, H.D., BRUNER, P.L. and BERRETT, D.G. 1987. A Field guide to the Birds of Hawaii and the Tropical Pacific. Princeton University Press, Princeton, New Jersey.

Kermadec Petrel, Kilauea Point NWR, Kaua'i, Summer 1999.

Christian Melgar, Hanalei, Kaua'i, Hawai'i / Worthing, West Sussex, England. 2000, updated 2003.

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