Monthly Marathon

nother (), obvi- ously! My commiserations Ato the unfortunate partici- pants in this competition who do not immediately jump up and down with excitement over the prospect of yet another gull chal- lenge, assuming, that is, that there are some left. It may seem, at first glance, that with an image as small as this there is not much prospect of a detailed plumage analysis, but close study reveals a sur- prising number of clues.While it should never be assumed that additional in the back- ground or foreground of mystery photographs are necessarily Bob Frost clues to solving the mystery – 63. Great Black-headed Gull , Kfar Rupin, Israel, sometimes they serve merely as a January 2000. potentially misleading distraction – the gull lurking in the back- ground of plate 24 (repeated a basic assessment of the ’s (when visible) as being those here as plate 63) may have size: are we dealing with a small, characteristic of a gull helped to determine the first medium-sized or large gull? In belonging to one of the three impression of many participants, practice, this first step seldom size groups, respectively small, but let’s come back to that later. requires more than the most medium-sized and large. In a pho- With so many on the cursory examination, but, when tograph like this, where there is West Palearctic List to choose you think about it, size determi- nothing alongside the bird to from, perhaps the best way to nation of a lone gull in a photo- provide even a subliminal clue to start is by eliminating as many as graph is usually based primarily its size, and where the plumage possible of the contenders. on recognition of the type of is perhaps not so immediately Usually, this process begins with plumage or the weight of the bill recognisable as being of a type associated with just one partic- ular size category of gull, it may be necessary to make an intu- itive guess. So, while this gull clearly is not one of the smaller species – it simply does not look like any of them – it may be wise to keep an open mind as to whether it is a medium-sized or a large gull. The most eye-catching plumage feature in this instance is undoubtedly the rather heavily spotted hindneck, especially towards the base, and the well- marked dark patches on each side of the back of the head, con- trasting sharply with an appar- 64. ‘Monthly Marathon’. Photo no. 176.Twenty-fourth stage in ently unmarked whitish crown. eleventh ‘Marathon’. Identify the species. Read the rules (see page The latter feature is reminiscent 55), then send in your answer on a postcard to Monthly Marathon, of the pattern exhibited by c/o The Banks,Mountfield, Robertsbridge, East Sussex TN32 5JY or Mediterranean Gull Larus by e-mail to [email protected], to arrive by 5th May 2001. melanocephalus in non-breeding

156© British Birds 94: 156-157, March 2001 Monthly Marathon plumages, but that species would mystery gull suggests that it tants in recent months, however, never show a strongly streaked could well be a Great Black- with just under half the entrants or spotted hindneck. Neverthe- headed Gull, in first-year (48%) correctly naming the less, the vague similarity to plumage. In addition to the dark mystery bird as a Great Black- Mediterranean Gull, echoed also band crossing the back of the headed Gull. A surprising by the bird in the background, head, it appears to have distinct number (28%) opted instead for which appears to have some sort dark marks on the rearmost ear- Larus canus, of a Mediterranean Gull-like dark coverts which would correspond while Ring-billed Gull Larus ‘mask’ and possibly a dark-tipped with Great Black-headed’s dark delawarensis was the next most pale bill, is a fairly strong pointer mask; the few visible juvenile popular option (10%). These to another species: Great Black- wing-coverts look solidly dark- results have affected a number of headed Gull L. ichthyaetus. centred, with no suggestion of the leading contenders. Christer Immature plumages of this enig- the variegated markings shown Kalenius is still out in front with matic species were poorly by most of the larger gulls. The an unbroken series now of ten known by European observers upperparts are rather uniformly correct answers. He is closely fol- until comparatively recently light grey, but there is a hint of lowed by a group of four with (Wallace 1973), but since then it diffuse darker centres to several nine-in-a-row (involving Peter has received a lot more atten- of the upper scapulars (fol- Lansdown, Andy Mears, Jakob tion, thanks mainly to the much- lowing the curve of the bird’s Sunesen and Peter Sunesen), increased activity of European right ‘shoulder’), another feature whilst behind them are Jon Holt birders in the Middle East. of many Great Black-headeds in on eight and Andy Rhodes on Readers of British Birds twenty their first winter. Those of us seven correct answers. years ago may remember one of who have had the advantage of A sequence of at least 13-in-a- the revelations in Peter Grant’s having observed Great Black- row is the requirement to find a seminal series of papers on the headed Gulls at the numerous winner of the current saga, so field identification of West bird-rich fish-ponds in northern the next three or four rounds Palearctic gulls (Brit. Birds 73: Israel in winter may have derived may be crucial…. 113-158), his explanation of additional clues from the artifi- Great Black-headed’s unusual cial-looking bank, the reflection References sequence of plumages, in some of a presumed Grey Heron Grant, P.J. 1980. Field identification ways more like that of a medium- Ardea cinerea and the general of west Palearctic gulls. Part 3. sized gull than that of one of the ‘haughty’ demeanour of the two Audouin’s, Herring, Lesser Black- large species. The drawings and gulls. backed, Great Black-backed and Great Black-headed Gulls. Brit. photographs featured in that With everything pointing so Birds 73: 113-158. article (and the many that have strongly to Great Black-headed Wallace, D. I. M. 1973. Identification been published in a wide variety Gull, there is really no need to go of some scarce or difficult west of sources since) illustrate the through the tiresome exercise of Palearctic species in Iran. Brit. remarkable similarity of the head ‘eliminating’ all the other big Birds 66: 376-390. and wing patterns of immature gulls, one by one; the mystery is Great Black-headed to those of as good as solved. These first- Killian Mullarney the much smaller Mediterranean winter Great Black-headed Gulls Gull, although the only time the were photographed at Kfar two species are ever likely to be Rupin, Israel, in January 2000 by confused is in competitions like Bob Frost. this. This proved one of the more Further scrutiny of our tricky photographs for contes-

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Monthly Marathon Rules – amendment Please note the following amendment to Rule 2 of the Monthly Marathon Rules: 2. Entries must be sent either by post,each one on a separate postcard,or by e-mail and be received at the British Birds Editorial Office (Monthly Marathon, British Birds Editorial Office,The Banks, Mountfield, Robertsbridge, East Sussex TN32 5JY; e-mail: [email protected]) by the stated closing date. Every care will be taken, but, even if negligence is involved, no responsibility can be accepted for non-delivery, non-receipt or accidental loss of entries.

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