Black-headed Gull (Larus ridibundus) with aberrant colours or leucisme

Black-headed Gull (Larus ridibundus), 22.7.2010, Følle Bund, Djursland

Black-legged Kittiwake (Rissa tridactyla), 3cy, 29.8.2010, Bovet Bugt, Læsø

Probable second summer Black-legged Kittiwake (Rissa tridactyla)

Lesser Black-backed Gull (Larus fuscus), 2cy, 27.8.2010, Aarhus Harbor

Possible first summer Baltic Gull (Larus fuscus fuscus), but an advanced intermedius cannot be safely ruled out.



The feather appearance and the moult progression indicates a first summer Baltic Gull (Larus fuscus fuscus). There's only one problem with the identification: it isn't ringed and therefore the true origin cannot be safely determined.

Besides the advanced body and primary moult the overall darkness of the upperparts indicates fuscus. Mantle, scapulars and parts of coverts are mostly renewed to an adult-like blackish type with a slight brownish tinge and some pale edges, but some coverts are also of the browner type which has black fuscus-like shaft-streaks (not anchor-like pattern as in graellsii/intermedius). Tertials are blackish with broad white tips, underwings have mostly clean white areas, head and underbody are also almost clean white whereas belly is all clean white. Tail has rather extensive black tail band and seems rather fresh and the bill is bicolored fleshy with blackish subterminal markings and cutting edges.

The outer most primaries are worn juvenile feathers. Naturally a more advanced primary moult would have supported fuscus ID far more, but some fuscus appear to retain the outer most primaries throughout their first summer. One could also claim that the proportions does not cry out for a classic fuscus which is slim, slender and highly elongated, but judging from photos proportions does seem vary quite some in Finland.

Other rather similar looking birds are here, here, here and here

Glaucous-winged Gull (Larus glaucescens), 5cy, 27.8.2010, Aarhus Harbor, Denmark

This evening I managed to relocate the Danish Glaucous-winged Gull in the most northern part of Aarhus Harbor, but again it was seen only for a few minutes before it flew off towards the eastern harbor.

As I was fully aware that it has a strange habit of allowing only short observations a few video recordings were made in haste as to document the record and illustrate the plumage state. Six minutes later it flew off towards southeast. The bird is apparently identical to the one seen in November and December 2009.

We hadn’t seen it for the last six months (since February) and therefore expected that it was only a winter visitor that had left the area by now, but apparently you’ll have to wait a while longer before it shows up at your local gull spot ;-)

Baltic Gull (Larus fuscus fuscus), ad, 6.8.2010, Hammeren, Bornholm

This Baltic Gull (Larus fuscus fuscus) was photographed at Hammeren on northwest Bornholm where two pairs are breeding in the local Herring Gull colony. It was seen flying back and forth along the cliffs on an overcast cloudy day and due to the weather it was hardly possible to take any well exposed photos of the flying bird up against the grey skies. Therefore the colour on the upperparts looks rather pale in some photos, but note that yet there is hardly any contrast between the black primary tips and the remaining dark upperparts.

Other features supporting ssp. fuscus is the overall slim and elongated appearance with slender body and long narrow wings with highly pointed wingtip. The dark upperparts also have a classical brownish wash on the coverts, there is only a small white mirror on P10 and whereas there is no white mirror on P9 beside a tiny white dot in the left wing.

Caspian Gull (Larus cachinnans), 1cy, 7.8.2010, Nexø Harbor, Bornholm (#2)

This beautiful Caspian Gull in almost complete juvenile plumage is all classical when it comes to plumage pattern and proportions. As seen in the first video where it preens its tail it has a broad black tail band and a rather unmark white tail base. In the second video the rather unmarked white underwings and central belly is visible. It has relative long legs with longer tibia; the bill is relative long and without pronounced gonys angle. It has a good cachinnans jizz with high push up breast, flat belly slightly dropped behind legs and long elongated slim rear.

Caspian Gull (Larus cachinnans), 1cy, 7.8.2010, Nexø Harbor, Bornholm (#1)

This beautiful Caspian Gull in almost complete juvenile plumage is all classical when it comes to plumage pattern and proportions. As seen in the video is has rather unmarked white underwings and central belly. It has relative long legs with longer tibia; the bill is relative long and without pronounced gonys angle. It has a good cachinnans jizz with high push up breast, flat belly slightly dropped behind legs and long elongated slim rear.



Note that left of the Caspian Gull stands a juvenile Baltic Gull (Larus fuscus fuscus) which is also a rather uncommon gull in Denmark.

Caspian Gull (Larus cachinnans), 4cy, 7.8.2010, Balka, Bornholm

This 3rd summer Caspian Gull has relative long legs with longer tibia compared to argentatus. The eye colour is relative dark with a slight green peppering in the iris – peppering most easily seen when light hits the eye directly - and when seen at some distance it stands out as being all dark in contrast to argentatus. There is a thin red orbital ring seen at close range. The bill is relative long and without pronounced gonys angle. The bare part colour in the opened bill is spot on for cachinnans being orangey-yellow at the base of the mandibles where the skin colour in michahellis is typical blood red and light pink in argentatus.

It has a good cachinnans jizz with high push up breast, flat belly slightly dropped behind legs and long elongated slim rear. P5 has been renewed and has a broad black band. P9 has only small mirror and p10 has the white mirror separated from the white apical which is spot on for a near-adult chachinnans.

The primary pattern on p9 and p10, the dark pattern on primary coverts, the partly retained dark tail band and the rather pale bill colour all indicate that the gull is a 3rd summer individual.

Caspian Gull (Larus cachinnans), ad, 7.8.2010, Nexø Harbor, Bornholm

This adult Caspian Gull has relative long and characteristic pale yellowish legs. Most often when seeing cachinnans their thinner legs and longer tibia compared to argentatus is quite distinctive. It has a good cachinnans jizz with high push up breast, flat belly slightly dropped behind legs and long elongated slim rear. Additionally the forehead and the back are both rather flat. The amount of black on p10 is spot on for chachinnans as the feather tip is all white and a huge grey tongue extends on especially inner web.