Wednesday, 28 March 2012

Thayer's Gull now with white balance set to shade

As it has been proposed that this gull which was originally identified as a Viking Gull is a Thayer’s Gull I have posted a selection of photos for you to scroll through. The gull was seen feeding in the shade behind a large building while the sun shone from a clear blue sky. Thus auto white balance in the camera produced some off coloured cold photos at firsts, but in this post I have set the white balance to shade.

The discussion takes place at

For comparison have a look at this nice photo by Peter Adriaens and this flying individual by Chris Gibbins.

Here are some more photos from California by Jeff Poklen and Chris Gibbins for comparison, whereas there are these photos from this side of the Atlantic at Birding Frontiers, the Irish Rare Birds Committee web, the Irish Bird Images and here.

Identification criteria in general are discussed here and at Surfbirds.

Please comment on the ID of this gull...

Note the dark brown tail with some white marks at the base of the retrices

Wednesday, 21 March 2012

Herring Gull (Larus argentatus) with leucisme

This 3cy Herring Gull (Larus argentatus) with colour aberrations was seen in Hirtshals Harbour in Denmark on 5 February 2012. Besides having the pure white feathers others are rather more dark pigmented than normal at this age class.

Friday, 2 March 2012

A record number of 27 white-winged gulls in just two days...

As my experience with Iceland Gulls in Denmark was limited the occurrence of numerous white-winged gulls in northwest Europe this winter made a unique opportunity to explore. Adding the possibility of a few Kumlien’s Gulls made it just pure pleasure to have two full weekend days on February 4-5 among the rare gulls in harbours along the West Coast of Jutland.

I managed to take photos of a record number of 27 true white-winged gulls and one Thayer's Gull. The individuals were 19 Kumlien's/Iceland Gull-types, 8 Glaucous Gulls and one Thayer's Gull. Even though the temperature dropped below -17 degrees C I loved every minute of it.

Kumlien’s Gull was not convincingly recorded in Denmark before this winters invasion so the intension with this post is to provide some overview which can help the Danish Rarities Committee in their future assessment of kumlieni claims.

The 19 Kumlien's/Iceland Gull-types have been categorised into different groups below and I hope people will comment and help reclassify the different individuals.

Kumlien's Gulls which Rarities Committees should accept:

These individuals have all been identified as Kumlien’s Gulls because they have either subtle dark shading on the outer webs of at least p6-p10; a faint 'ghost mirror' on P10; faint dark shading on p6-p9 reaching the primary tips or sub-terminal bands on the outer primaries.

The dark shading on outer primaries of especially second winter individuals is as least as dark as the shading on primary coverts and the outer primaries are darker or at least not paler than the inner primaries.

#1.1: 3cy, 5.2.2012, Hirtshals Harbour

#1.2: 4cy, 5.2.2012, Hanstholm Harbour

#1.3: 4cy, 5.2.2012, Hanstholm Harbour

#1.4: 4cy, 5.2.2012, Hirtshals Harbour

Individuals which Rarities Committees should not accept as they are currently not without doubt

Identification of these examples is not so straightforward. All of these individuals may be Kumlien’s Gulls, however they are currently considered to be well-marked Iceland Gulls. Most individuals have rather dark peppered eyes, light grey marbling on outer webs of outer primaries, some faint pigmentation along the tip of the outer primaries (sub-terminal bands) and some photos give the impression of a diluted version of a “string of pearls”. However, note that it is not abnormal for 2nd- and, especially, 3rd-cycle glaucoides to show a brown wash on the outer primaries. The plumage of such well-marked immature gulls often looks quite retarded, with still lots of brown in the wing. Note that the brown wash on outer primaries of such birds simply matches the brown wash on outer secondaries, as is often the case in other 3rd-cycle gulls (e.g. Herring Gull). It is therefore considered just to be a trait of immature plumage.

#2.1: 3cy, 4.2.2012, Hvide Sande Harbour

#2.2: 3cy, 5.2.2012, Hanstholm Harbour

#2.3: 3cy, 5.2.2012, Roshage, Hanstholm

#2.4: 4cy, 4.2.2012, Hvide Sande Harbour

#2.5: 4cy, 4.2.2012, Hvide Sande Harbour

#2.6: 4cy, 5.2.2012, Hirtshals Harbour

#2.7: 5cy, 5.2.2012, Hirtshals Harbour

#2.8: 5cy, 5.2.2012, Hirtshals Harbour

Putative Iceland Gull

These gulls which have all been recorded during the record influx of Kumlien’s Gulls are labeled as putative Iceland Gull instead of calling them definite Iceland Gulls. This line was followed because completely white-winged Kumlien’s Gull is claimed to be indistinguishable from glaucoides Iceland Gull.

#3.1: 3cy, 4.2.2012, Hvide Sande Harbour

#3.2: 3cy, 5.2.2012, Hanstholm Harbour

#3.3: 3cy, 5.2.2012, Hanstholm Harbour

#3.4: 3cy, 5.2.2012, Hirtshals Harbour

#3.5: 4cy, 4.2.2012, Hvide Sande Harbour

#3.6: 5cy, 4.2.2012, Hvide Sande Harbour

#3.7: 5cy+, 5.2.2012, Hirtshals Harbour

When I look at the excellent work by Howell and Mactavish (2003). I think one type may be missing. It is the type where the outer webs of the outer primaries are not obviously dark pigmented and approach the type A (stage 0) or somewhere between the type A (stage 0) and type B-C (stage 1) except for the presence of faint subterminal bands near the tip of at least p8-p9. Sometimes there is the impression of a faint “string of pearls” due to the pigmentation on inner primary webs reach further towards the tip than what I find typical for glaucoides. One could argue that such a primary pattern would fit in right with the type D-F (stage 2) with respect to the subterminal primary band, whereas the colouring of the outer webs would fit in between type Aa (stage 0) and type B-C (stage 1).

Several such individuals have been seen in Denmark this winter and we have trouble to decide what to think of them. Do such individuals ever occur in Newfoundland? Any comments are more than welcome...


Howell, S.N.G. & Mactavish, B. 2003. Identification and variation of winter adult Kumlien's Gulls. Alula 9:2-15.