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Swinhoe's Storm Petrel Oceanodroma monorhis: new to the waters of the United Arab Emirates.

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Along with a resident group of birders in the United Arab Emirates, I had participated in weekly pelagic trips out of Khor Kalba, on the coast of the Gulf of Oman, with local boatman Abdullah Al Zaabi throughout the summer of 2011. It was proving a very good year so far for seabirds, with high numbers of Sooty Puffinus griseus and Flesh-footed Shearwaters P. carneipes as well as the first ever records of Cory's Shearwater Calonectris borealis for the UAE. Throughout June and July, Wilson's Petrels Oceanites oceanicus had been well represented and numbers had risen to a maximum count of 45 on 28th June. However, we were always aware of the possibility of Swinhoe's Storm Petrel Oceanodroma monorhis, especially since that species is recorded almost annually off the coast of Oman.

Most of our previous pelagic trips had been out to around 25 km but on 8th August, we managed to venture out much further. We left Khor Kalba at 3pm and headed out to a deep water fishing site in search of tuna. At around 35 km from shore, at coordinates N 25 12.668 E /56 42.109, I spotted a storm petrel off to the starboard (right) side of the boat and, as we slowed and managed to get a first glimpse, we were immediately struck by two things: This bird was a completely different in size and structure to Wilson's Storm Petrel, and it had an all-dark rump. We knew immediately that we were probably watching a Swinhoe's Storm Petrel.

A chase ensued as Abdullah skilfully followed and drove alongside the bird, allowing excellent views and for photographs to be taken. At one point, the bird was watched as it flew alongside a Wilson's Storm Petrel low over the sea, allowing a convenient comparison of size and shape to be made. Once satisfied with the identification, we headed back in the direction of the tuna site but after another short journeytime at high speed, Graham Talbot spotted located another bird. Again, as we slowed, it was clear that we had found a second Swinhoe's Storm Petrel, and with some more manoeuveringmanoeuvering by Abdullah, further photographs of this second bird were obtained.

When out at the 50 km mark, we had a rather fruitless attempt at fishing but, as we raced back to shore with the light starting to fade, our paths crossed with one last bird over an otherwise bird-less sea. This time it was a magnificent Jouanin's Petrel Bulweria fallax, with its characteristic arcing flight--the second record of this species for the UAE.

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With this discovery of both Swinhoe's Storm Petrel and Jouanin's Petrel at a range that had previously rarely been visited, subsequent trips in August and September 2011 after this date involved the long journey out to the 50km mark. Participants were not disappointed as Swinhoe's Storm Petrels were located on a further four occasions: on 19th August (2 birds), 26th August (5 birds), 2nd September (3 birds) and 9th September (1 bird). All records outlined here have been accepted by the Emirates Bird Records Committee, EBRC.

Description

Size and structure of a large, long-winged storm petrel with a long, slightly notched tail and overall quite similar in structure to Leach's Storm Petrel O. leucorhoa. The Swinhoe's was roughly 1.5 times the size of Wilson's Storm Petrel with much longer, straighter wings and a longer tail. There were no feet extending beyond the tail, normally a feature of Wilson's Storm Petrel. The flight action was very different to Wilson's, being more direct with lower downbeats.

The plumage was dark brown all over with black primaries and secondaries. There was a prominent pale carpal bar on the upper-wing of both birds. From photographs, short white bases to the outermost three primaries can be seen, giving the impression of a small "skua-flash". This was not noticed in the field. The rump and under-tail coverts were clearly dark on both birds. The head, upper-parts and upper-wing coverts actually appeared a slightly paler, chocolate brown; this that was noticeably different to the darker Wilson's Storm Petrel.

Some of the features outlined here are discernible in the images that accompany this paper.

Similar Species

There are a number of similar dark-rumped storm petrels that occur in the North Pacific but only two species show white bases to the shafts of the outer primaries. These are Swinhoe's Storm Petrel and Matsudaira's Storm Petrel O. matsudairae. The latter can be discounted as it has a much more prominent white flash to the base of the primaries that is clearly visible in the field and has a much more deeply forked tail (Brazil 2009). A third species, Markham's Storm Petrel O. markhami, occurring in the south-east Pacific, can also show white bases to its primaries as distinct as Swinhoe's but, like Matsudaira's, Markham's Storm Petrel has a much more deeply forked tail (Garner and Mullarney, 2004).

Range

Swinhoe's Storm Petrel breeds in the northwest Pacific on remote islands off the coast of China, Japan and Korea. It migrates southwest around the East Indies to winter in the warmer Indian Ocean (Onley and Schofield, 2007). Like all storm petrels, it nests in colonies close to the sea and, being a strictly pelagic species outside the breeding season, it spends the rest of the year on the open ocean. Its non-breeding range extends far across the Indian Ocean to the east coast of Africa and the Arabian Sea. It is now known that the waters around the Singapore Strait are a key passage area for migrating Swinhoe's Storm Petrels, with over 500 being recorded in September 2011. (Poole et al, 2011)

There are 36 accepted records for Swinhoe's Storm Petrel in Oman to date, the first being in November 1997, following a cyclone in the Indian Ocean. That month, a maximum count of 99 birds was recorded from Ra's Janjari on 10th November. Since 1997, they have been observed most years in Oman but, interestingly, 2011 was a particularly good year for the species with nine records. These included a record of 4 birds seen from Muscat on 6th September 2011 (Jens Eriksen, pers comm.)

The first record of Swinhoe's Storm Petrel for the Western Palearctic was of a bird seen from Eilat, Israel on the Red Sea in 1958. Surprisingly, given their known breeding range, there have been several records in the North Atlantic. The first of these was a bird trapped on Madeira in 1983 and subsequently there were a number of records from the United Kingdom in the early 1990s, where three individuals were trapped over a five year period (Cubitt 1995). The identity of these three birds was confirmed after the study of vocalisations and DNA sequencing. In fact, as a result of these records of Swinhoe's Storm Petrel in the North Atlantic, it has been suggested that there is a small breeding population somewhere in the Atlantic Ocean (Brazil 2009). However, this has not been proven.

Oscar Campbell, Chairman of the Emirates Bird Records Committee, has commented as follows:

The acceptance of this (and subsequent records in 2011) as Swinhoe's Storm-Petrel was straightforward. Photographic evidence accompanied each record and most committee members managed to see at least one or two of these wonderful and enigmatic birds. The established occurrence of the species in Omani waters, including records from as near as Muscat, made occurrence in UAE waters eminently feasible and the timing of UAE records in 2011 fits in well to the apparent pattern of records from Oman.

Acknowledgements

I would like to thank Tommy Pedersen for supplying me with pelagic records from the UAE and Hanne and Jens Eriksen for supplying me with data on the occurrence of Swinhoe's Storm Petrel in Oman. I am also grateful to Khalifa Al Dhahiri and Steve James for the use of their photographs.

References

Brazil, M. 2009. Birds of East Asia. Christopher Helm, London.

Cubitt, M. 1995. Swinhoe's Storm-petrels at Tynemouth: new to Britain and Ireland. British Birds 88: 342-348

Garner, G. and Mullarney, K. 2004. A critical look at the evidence relating to the 'Chalice petrel'. British Birds 97: 336-345

Onley, D. and Scofield, P. 2007. Albatrosses, Petrels and Shearwaters of the World. Christopher Helm, London.

Poole, C., Brickle, N. and Bakewell, D. 2011. Pelagic Birding: South-East Asia's final frontier. Birding ASIA 16: 26-31

Simon Lloyd, The English College, Dubai, PO Box 11812, UAE.

email: simonpeterlloyd@googlemail.com
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Author:Lloyd, Simon
Publication:Tribulus
Geographic Code:7UNIT
Date:Jan 1, 2012
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