www.gull-research.org

A dark Iceland gull today in Holland, showing obvious dark subterminal markings in the outer primaries.
Enough for kumlieni or wishful thinking?

http://waarneming.nl/waarneming/view/46280292#


Theo Muusse

I have been lucky enough to see this bird but without the proper equipment. A very dark bird indeed! Coarsely marked scapulars and coverts, obvious tail bar and dark secondaries. It had a paler bill base though, not sure if this is problematic?

Hope to take better pictures tomorrow.

And dark subterminal markings on p6-p9 easily visible?

Theo

Not a Kumlien's, in my opinion...
First-cycle birds are often the most difficult to identify with certainty. In December 2005, I had a discussion with Klaus Malling Olsen on this topic, and he provided the following helpful characters for a vagrant kumlieni in this plumage:

- a distinct brown tinge on the outer webs of the outer primaries. Note the word 'outer' (which is important). Also, as a personal rule of thumb, I compare the colour of the outer webs with that of the primary coverts. The brown tinge should be about as dark as the primary coverts, preferably darker. It is often present up to the base of the feather, so rather than focus on any dark marks near the tip of the primaries, I would concentrate more on the bases of these feathers.
- uniformly dark tail band (<> rather barred in the Amsterdam bird)
- blackish bill

Some examples are here. The plumage is really variable and overlaps with Iceland Gull. The more of the three characters the bird has, the better. My first impression on the photos from Amsterdam is that this bird shows probably none ?

See also this Belgian Iceland Gull (not Kumlien's), which sparked the above discussion in winter 2005:
http://www.keeponbirding.com/foto.jsp?i ... rentId=472
http://www.keeponbirding.com/foto.jsp?i ... rentId=472
http://www.keeponbirding.com/foto.jsp?i ... rentId=472

Peter pretty much sums up the current characters for 1st cycle kumlieni and such kumlieni are the only ones I would dare call kumlieni. On the other hand - as Peter mentioned, 1st cycles are often very difficult to identify for certain and you often feel quite uncomfortable when seeing intermediate birds.

Steve's bird below shows much of the features mentioned, although the secondaries might seem on the dark side for the average kumlieni but roughly the same colour as the covert region. Some have clearly darker inner secondaries, with obvious contrast to coverts.

http://www.birdersplayground.co.uk/Kuml ... years.html

http://www.peregrineprints.com/Gulls/ICGU_THGU.htm

http://www.pbase.com/derekcharles/root

Also interesting with these from Japan:

http://www23.tok2.com/home/jgull/090330/E_kum1w.html

http://www23.tok2.com/home/jgull/090203/kumlieniE.html

Jan

When seeing this pic, I still doubt the primaries are too pale.

http://www.dutchbirding.nl/gallery.php? ... 226&page=1

The bill and tail are not okay..

Theo

When seeeing all the images of the Amsterdam bird - the impression varies according to what image you chose. The one above Theo's pick:

http://www.dutchbirding.nl/gallery.php? ... 227&page=1

shows darker outer web on all primaries except p10 and a slight contrast in the primaries - but the reverced to what you normally would want for a possible kumlieni, namely paler outer primaries and slightly darker inner. Some kumlieni would lack contrast altoghether (http://www.pbase.com/jpkln/image/39952045) and those are the tricky ones and thus similar to pale glaucoides. Not however, to be taken lightly, variation makes the trouble.

Derek's glaucoides here would probably show the mentioned contrast in a flight shot, note the pale outer webs of the outer primaries:

http://www.pbase.com/derekcharles/image/92062685

What about this one then?

http://www.pbase.com/derekcharles/image/92239403

rather similar to this one:

http://www.pbase.com/derekcharles/image/94309865

Jan

That may be worth looking for, the outer primes being darker than the inner.
Note that the bottom link shows a bird named kumlieni but with pale bill.
The tail-band looks plain.

Theo

Theo Muusse wrote:That may be worth looking for, the outer primes being darker than the inner.
Note that the bottom link shows a bird named kumlieni but with pale bill.
The tail-band looks plain.

Theo

Bill and tail pattern is within the variation for kumlieni. Then of course one can argue that the bill of kumlieni looks heavier compared to the average glaucoides but that´s not always a fact.

Jan

What about this one then?

http://www.pbase.com/derekcharles/image/92239403

Hello Jan,
The apparent Kumliens like pattern of this bird was caused by a photographic effect. The bird was a standard Iceland Gull but in this one photo only it appears to have brown wash on the outer web of the outer primaries. Not sure what caused it. Will try and hunt out the other pictures of this bird. Should have known your sharp eyes would see it!

derek