Iceland Gull
Larus glaucoides glaucoides


Photographer

Dick Newell

Date

22nd November 01

Location

Milton, Cambs.

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This juvenile bird certainly has a lot of brown in its primaries and also a fairly densely marked tail - is it good enough for Kumlien's? It is a small bird, much smaller than any of the Lesser Black-backed or Herring Gulls around it. In flight the tail did not look so heavily patterned, much paler with a very narrow sub-terminal line. If it is glaucoides, it is very heavily marked, which could be explained in part by the early date and lack of bleaching and wear. If it's kumlieni, then it is a very cute looking one which could be because it is a female.

Postscript: Overwhelming opinion is that this is indeed a juvenile glaucoides at the coarse end of the spectrum. Thanks to Richard Patient and Simon Stirrup for their input and especially to Richard Millington who volunteered the following insightful analysis:

This bird neatly illustrates all the classic features of a 'coarse' Iceland Gull (to the exclusion of Kumlien's).

It has the classic glaucoides shape (including weak, largely pinky-based bill, often larger and darker in kumlieni).

It shows lots of dark pigmentation, but the distribution and pattern of it is indicative of glaucoides.

Taking the four important parts:

1. The primaries. Although plainly milky-brown for most of their length, there is actually a paling at the tips and, more importantly, there is a dark subterminal spear-tip mark on each visible primary (separated from the milky webs by a pale area). All the primaries seem to be of a similar hue. This patterning matches 'dark' Iceland Gull. Ideally, a Kumlien's would show a more simple pattern, of milky brown feathers (getting darkest towards the outer primaries), each neatly fringed with a diffuse pale edge, with any patterning at the tip being less defined.

2. The tail. This bird shows a marbled or 'fishbone' pattern on the tail; it is somewhat barred and there is no real tail-band effect. One of the more standard features of Kumlien's (if anything is standard...) is the tail-band. Each tail feather tends to be more or less plainly pigmented brownish, either wholly or just subterminally, so producing the effect of a tail-band. On those that show a more broken pattern, the brown seems to arrange itself in a more 'tail-bandy' sort of way.

3. The tertials. Although heavily-marked, there is no 'in-filling' or muddy basal areas on the tertials (this seems to happen quite commonly on those Kumlien's that show this much dark on the tertials).

4. The body. The overall rather finely-freckled, buff-oatmealy head and body pattern is typical 'coarse' glaucoides, whereas kumlieni are often rather plainer-looking (or purer pigmented?)

Having said all this, kumlieni is a variable feast and (especially if it really is a hybrid taxa with Thayer’s) some may look exactly like this. However, since it actually looks so like a glaucoides, it would get my vote for being exactly that. And a cracker to boot....
Richard Millington


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