The controversy with the Kumlien's Gull

We struggle to define the threshold for confident identification of out of range occurring Kumlien’s Gulls and it is often reduced to a one-sided question: “Where can we draw the line so that we are sure the accepted records of Kumlien’s Gull are correct? Since the goal is high confidence, this leads to a narrow definition of Kumlien’s Gull – only the well pigmented which ghost the overall pattern like a subdued Thayer's Gull are named and reported as Kumlien’s. This leads to two problems. First, we only identify part of the population – some pale Kumlien’s are excluded. Second, many of those pale and faint pigmented individuals are simply lumped into our definition of Iceland Gull, and receive no extra attention. There is nothing wrong with excluding some pale Kumlien’s from being called Kumlien’s, as long as birders understand that some Kumlien’s are being excluded. This is conservative. But most people give Kumlien’s Gull and Iceland Gull very uneven treatment by demanding that Kumlien’s meet high standards, and then calling everything else Iceland Gull. This is not conservative. We should at least be fair and apply equally strict criteria to our Iceland Gull identifications. Calling it an Iceland Gull, when it is really a possible Kumlien’s Gull could be just as wrong as naming it as a definite Kumlien’s Gull.

The identification is challenging because Kumlien’s Gull seem to show an unbroken continuum of variation from being almost as dark as a Thayer’s Gull to be pale and white-winged as an Iceland Gull, and there are no fully reliable plumage differences between the latter and the extreme pale Kumlien’s Gulls. The controversy with the Kumlien’s Gull-Iceland Gull identification, however, is part fuelled by a desire to name every individual. That some observers would be happier to call a gull an Iceland Gull even though faint pigmentation is present in its outer primaries may be more through conservatism than accurate identification. Using the term ID uncertain is probably more appropriate and realistic.

Is this pattern enough to claim a pale Kumlien’s Gull or is it a pigmented Iceland Gull?

Kumlien's Gull (Larus [glaucoides] kumlieni), 4cy, 5.2.2012, Hirtshals Harbour

This is the seventh of eight white-winged gulls found in Hirtshals Harbour in just one afternoon, with seven Kumlien's/Iceland Gull-types and one 2cy Glaucous Gull.

It has been identified as a Kumlien's Gull and was originally found on January 21. Since then it has been documented with several great photos such as e.g. on these dates: January 21, January 23 and January 29.

Iceland Gull (Larus glaucoides), 4cy, 5.2.2012, Hirtshals Harbour #4

This is the sixth of eight white-winged gulls found in Hirtshals Harbour in just one afternoon, with seven Kumlien's /Iceland Gull-types and one 2cy Glaucous Gull.

It is considered to be an Iceland Gull though this is not to say it is not Kumlien's Gulls. It has without doubt some rather dark peppered eyes, distinct pigmentation along the tip of the outer primaries and the pearl grey colour on the inner web is intensified in colour towards the tip of the outer primaries thus creating the impression of “a string of pearls” which is good for Kumlien’s. However, whether these characters are considered sufficient to claim a Kumlien's in Europe I will leave unanswered and put it down as an Iceland Gull for now. Other photos of the same individual were taken on January 21 and Februar 25. Any comments are more than welcome.

The primary pattern is just about identical to this and this from Hirtshals and this from Hanstholm. The latter has been identified as a Kumlien's Gull by local people due to the faint dark pigmentation along the very tip of the outer primaries.

Iceland Gull (Larus glaucoides), 5cy, 5.2.2012, Hirtshals Harbour #3

This is the fifth of eight white-winged gulls found in Hirtshals Harbour in just one afternoon, with seven Kumlien's /Iceland Gull-types and one 2cy Glaucous Gull.

It is considered to be an Iceland Gull though this is not to say it is not Kumlien's Gulls. It has without doubt some rather dark peppered eyes, faint pigmentation along the tip of the outer primaries and a few photos even gives the impression of a faint version of “a string of pearls” which is good for Kumlien’s. However, whether these characters are considered sufficient to claim a Kumlien's in Europe I will leave unanswered and put it down as an Iceland Gull for now. Another photo taken on January 21 of what is believed to be the same individual can be seen here. Any comments are more than welcome.

The primary pattern is just about identical to this and this from Hirtshals and this from Hanstholm. The latter has been identified as a Kumlien's Gull by local people due to the faint dark pigmentation along the very tip of the outer primaries.

There were three almost identical near-adult Iceland Gulls in the harbour. Luckily they were all seen at the same time late in the afternoon; however, if you look careful and compare with this and this you will also see that there are slight differences in the extent of their winter shawl.

Iceland Gull (Larus glaucoides), 5cy+, 5.2.2012, Hirtshals Harbour #2

This is the fourth of eight white-winged gulls found in Hirtshals Harbour in just one afternoon, with seven Kumlien's /Iceland Gull-types and one 2cy Glaucous Gull.

It is considered to be an Iceland Gull though this is not to say it is not Kumlien's Gulls. It has without doubt some rather dark peppered eyes.

There were three almost identical near-adult Iceland Gulls in the harbour. Luckily they were all seen at the same time late in the afternoon; however, if you look careful and compare with this and this you will also see that there are slight differences in the extent of their winter shawl.

Here behind one of the slightly pigmented Iceland Gulls if such actually exists or the potential very pale Kumlien’s Gull...

Iceland Gull (Larus glaucoides), 5cy, 5.2.2012, Hirtshals Harbour #1

This is the third of eight white-winged gulls found in Hirtshals Harbour in just one afternoon, with seven Kumlien's /Iceland Gull-types and one 2cy Glaucous Gull.

It has been documented by others with several great photos such as on these from: January 14, January 19 and January 21.

It is considered to be an Iceland Gull though this is not to say it is not Kumlien's Gulls. It has without doubt some faint pigmentation along the tip of the outer primaries and the pearl grey colour on the inner web extends further towards the tip of the outer primaries than typically in glaucoides, a few photos even gives the impression of “a string of pearls” which is good for Kumlien’s. However, whether the characters are considered sufficient to claim a Kumlien's in Europe I will leave unanswered and put it down as an Iceland Gull for now.

The primary pattern is just about identical to this and this from Hirtshals and this from Hanstholm. The latter has been identified as a Kumlien's Gull by local people due to the faint dark pigmentation along the very tip of the outer primaries.

There were three almost identical near-adult Iceland Gulls in the harbour. Luckily they were all seen at the same time late in the afternoon; however, if you look careful and compare with this and this you will also see that there are slight differences in the extent of their winter shawl.

Here seen in front of the fourth Iceland Gull.

Kumlien's Gull (Larus [glaucoides] kumlieni), 3cy, 5.2.2012, Hirtshals Harbour

This is the second of eight white-winged gulls found in Hirtshals Harbour in just one afternoon on January 5, with seven Kumlien's/Iceland Gull-types and one 2cy Glaucous Gull.

It has been identified as a Kumlien's Gull due to the dark outer webs contrasting with the pale inner webs on the outer 4 to 5 primaries in combination with relatively pale and unmarked inner primaries, a 'ghost mirror' on P10, whitish secondaries, definitely much paler than the outer primaries and finally plumage wise a rather complete tail band. So the overall pattern is like a subdued Thayer's Gull of this age.

It was originally found on January 13 and has since then been documented with several great photos such as: January 13, January 14, January 16 and January 21.