31 July 2013

Bird resembling a Taimyr Gull Larus taimyrensis – Al Khobar

After doing some more thinking and investigation into the pale Steppe Gull Larus barabensis I saw in Al Khobar, Eastern Province of Saudi Arabia on 30th November 2012, I have the following points to raise. Initially the bird looked like a Caspian Gull Larus cachinnans due to its pale mantle colour, which was considerably paler than all of the surrounding Steppe Gulls and Heuglin’s Gulls Larus heuglini, but the wing pattern and structure made the bird look more like a Steppe / Heuglin’s Gull. I only managed to get a single photo of the bird as they were disturbed just as I got my camera out. The photo I did take is, however, is quite a decent one so many details can be seen. It certainly lacks many of the typical Steppe Gull features, associated with typical birds in the region and has quite a strong resemblance to Taimyr Gull Larus taimyrensis. Comparing my photo to pictures published in Taimyr Gulls: evidence for Pacific winter range, with notes on morphology and breeding - Klaas van Dijk, Sergei Kharitonov, Holmer Vonk & Bart Ebbinge (Dutch Birding 33: 9-21, 2011), although admittedly taken at a different time of year, show strong resemblances. I contacted Klaas to ask his opinion but he was unable to shed any light on the bird as it is away from the breeding area.

Adult Larus taimyrensis generally resemble Herring Gull Larus argentatus in size and shape. The upper-parts coloration is darker than in argentatus breeding in the Netherlands, being more similar to Yellow-legged Gulls Larus michahellis breeding in the Mediterranean. The legs are short to medium in length and rather stout. Most individual’s exhibit dull yellows legs but variation is extensive, legs being pink or grey­ish in some individuals. The iris is pale yellow or ochre, with a variable amount of dark speckling. The orbital ring and gape are usually orange-red. The bill is relatively short, firm and rather blunt with a weak gonydeal angle and with an extensive red gonys spot restricted to the lower mandible. The wing pattern usually shows an isolated mirror in a largely black p10, relatively small apical spots to the outer primaries and dark markings extending to p4.

Ring recoveries indicate that taimyrensis spend the winter in coastal areas in the north-western Pacific and that they cross the mainland of Asia in a south-easterly direction when migrating from the breeding grounds towards the wintering areas. As a result they appear unlikely to occur in the Arabia Gulf region, although this cannot be entirely ruled out. There are indications, but no ring recoveries, that taimyrensis might predominantly winter in a quite mild environment, most likely in coastal areas of the East China Sea and the South China Sea. More observations of birds marked on Taimyr and more insight in the winter ecology are needed to establish its core winter range and to get a better picture of the migration route. Furthermore, observations of marked birds are necessary to clarify if Taimyr Gulls also spend the winter in coastal areas around the Arabian Sea, or elsewhere along a south-westerly flyway. Recent sources indicate that gulls resembling Taimyr Gulls spend the winter in low numbers in southern Iran (Scott 2007) and Bahrain (Yésou & Hirschfeld 1997). The term "Big Pale heuglini" refers to the small number of birds seen in Bahrain (and elsewhere in the Persian Gulf region) that where previously considered to be taimyrensis. Compared to the normal Bahrain heuglini these birds are generally paler, larger, longer-legged, show more flesh tones in the legs, have longer bills and more angular heads, and perhaps average a larger P10 mirror and more often have a small P9 mirror. There is a possibility that a small number of unidentified large white-headed gulls seen at Okha, western India, described and depicted in Buchheim (2006) may also be taimyrensis.

There are no confirmed records of Taimyr Gull in Saudi Arabia, United Arab Emirates or Israel and it is not mentioned in the latest Kuwait List although Steppe Gull is a common passage migrant and winter visitor. This bird maybe another example and shows at least the type of birds that occur in the Arabian Gulf, which look like Taimyr Gull even if they cannot be proven to be such.